//Practical (Greet Application)
//Create an Android App that demonstrates working with one EditText and one TextView. User will enter his/her name in EditText and “Good morning, username” should be displayed in TextView as well as show message in Toast.

activity_main.xml File

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/btnShow"
        android:layout_width="233dp"
        android:layout_height="52dp"
        android:layout_alignParentTop="true"
        android:layout_marginStart="89dp"
        android:layout_marginLeft="89dp"
        android:layout_marginEnd="89dp"
        android:layout_marginRight="89dp"
        android:layout_marginBottom="136dp"
        android:text="Click me!"
        android:onClick="Greet"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="1.0"
        app:layout_constraintStart_toStartOf="parent" />

    <TextView
        android:id="@+id/textView"
        android:layout_width="109dp"
        android:layout_height="27dp"
        android:layout_marginStart="16dp"
        android:layout_marginLeft="16dp"
        android:layout_marginEnd="21dp"
        android:layout_marginRight="21dp"
        android:layout_marginBottom="100dp"
        android:text="Enter Name : "
        android:textAppearance="@style/TextAppearance.AppCompat.Body2"
        app:layout_constraintBottom_toTopOf="@+id/btnShow"
        app:layout_constraintEnd_toStartOf="@+id/edName"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.564" />

    <EditText
        android:id="@+id/edName"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="30dp"
        android:layout_marginLeft="30dp"
        android:layout_marginEnd="43dp"
        android:layout_marginRight="43dp"
        android:layout_marginBottom="100dp"
        android:ems="10"
        android:hint="Enter your name"
        android:inputType="textPersonName"
        app:layout_constraintBottom_toTopOf="@+id/btnShow"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toEndOf="@+id/textView"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.564" />

    <TextView
        android:id="@+id/txtName"
        android:layout_width="192dp"
        android:layout_height="33dp"
        android:layout_marginStart="109dp"
        android:layout_marginLeft="109dp"
        android:layout_marginTop="128dp"
        android:layout_marginEnd="110dp"
        android:layout_marginRight="110dp"
        android:layout_marginBottom="113dp"
        android:text="TextView"
        app:layout_constraintBottom_toTopOf="@+id/btnShow"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/edName" />


</androidx.constraintlayout.widget.ConstraintLayout>

MainActivity.java File

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
    protected EditText ed1;
    protected TextView tv1;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ed1 = (EditText) findViewById(R.id.edName);
        tv1 = (TextView) findViewById(R.id.txtName);
    }
    public void Greet(View view){
        String s,m;
        s = ed1.getText().toString();
        m = "Good Morning " + s;
        Toast.makeText(getApplicationContext(), m, Toast.LENGTH_SHORT).show();
        tv1.setText(m);
    }
}






//Practical (Create an Android App that demonstrates Activity lifecycle and instance state.)

acttivity_main.xml File

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Activity LifeCycle"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

MainActivity.java File

import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;

public class MainActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Log.d("Activity Lifecycle","onCreate invoked");
    }
    @Override
    protected void onStart() {
        super.onStart();
        Log.d("Activity Lifecycle","onStart invoked");
    }
    @Override
    protected void onResume() {
        super.onResume();
        Log.d("Activity Lifecycle","onResume invoked");
    }
    @Override
    protected void onPause() {
        super.onPause();
        Log.d("Activity Lifecycle","onPause invoked");
    }
    @Override
    protected void onStop() {
        super.onStop();
        Log.d("Activity Lifecycle","onStop invoked");
    }
    @Override
    protected void onRestart() {
        super.onRestart();
        Log.d("Activity Lifecycle","onRestart invoked");
    }
    @Override
    protected void onDestroy() {
        super.onDestroy();
        Log.d("Activity Lifecycle","onDestroy invoked");
    }
}

AndroidManifest.xml File

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.activitylifecycle"> //Ye line change krna apne application ke naam se

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="Activity LifeCycle"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>
</manifest>






//Practical(Create an Android App that demonstrates use of Option menu.)

activity_main.xml File

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/relativeLayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <TextView
        android:id="@+id/text"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Android Option Menu"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
    <TextView
        android:id="@+id/text1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/text" />
</androidx.constraintlayout.widget.ConstraintLayout>

menu_main.xml File(Create a folder with name "menu" and create a xml file named "menu_main")

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:android="http://schemas.android.com/apk/res/android">
    <item
        android:id="@+id/notification"
        android:title="Notification" />
    <item
        android:id="@+id/help"
        android:title="Help" />
    <item
        android:id="@+id/setting"
        android:title="Setting" />
    <item
        android:id="@+id/logout"
        android:title="Logout" />
</menu>

MainActivity.java File

import android.os.Bundle;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.widget.TextView;
import android.widget.Toast;
import androidx.appcompat.app.AppCompatActivity;
public class MainActivity extends AppCompatActivity {
    TextView text;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        text=(TextView)findViewById(R.id.text);
    }
    @Override
    public boolean onCreateOptionsMenu(Menu menu){
        MenuInflater menuInflater=getMenuInflater();
        menuInflater.inflate(R.menu.menu_main,menu);
        return true;
    }
    @Override
    public boolean onOptionsItemSelected(MenuItem item){
        switch(item.getItemId()){
            case R.id.notification:
                Toast.makeText(this,"Notification",Toast.LENGTH_SHORT).show();
                break;
            case R.id.help:
                Toast.makeText(this,"Help",Toast.LENGTH_SHORT).show();
                break;
            case R.id.setting:
                Toast.makeText(this,"Setting",Toast.LENGTH_SHORT).show();
                break;
            case R.id.logout:
                Toast.makeText(this,"Logout",Toast.LENGTH_SHORT).show();
                break;
            default:
                break;
        }
        return super.onOptionsItemSelected(item);
    }
}




//Practical (Create an Android App that demonstrates Screen Navigation using App Bar and Tabs)

activity_main.xml File

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <com.google.android.material.tabs.TabLayout
        android:id="@+id/tablayout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
        <com.google.android.material.tabs.TabItem
            android:id="@+id/item1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Tab 1" />
        <com.google.android.material.tabs.TabItem
            android:id="@+id/item2"
            android:nextFocusRight="@id/item3"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Tab 2" />
        <com.google.android.material.tabs.TabItem
            android:id="@+id/item3"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Tab 3" />
    </com.google.android.material.tabs.TabLayout>
    <androidx.viewpager.widget.ViewPager
        android:id="@+id/viewpager"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
</RelativeLayout>


fragment_page1.xml File

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <RelativeLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center">
        <TextView
            android:id="@+id/displayContent"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Title" />
        <TextView
            android:id="@+id/description"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@+id/displayContent"
            android:text="Description" />
    </RelativeLayout>
</FrameLayout>

VPAdapter.java File

import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentPagerAdapter;
import java.util.ArrayList;
public class VPAdapter extends FragmentPagerAdapter {
    private final ArrayList<Fragment> fragmentArrayList = new ArrayList<>();
    private final ArrayList<String> fragmentTitle = new ArrayList<>();
    public VPAdapter(FragmentManager fm)
    {
        super(fm);
    }
    @Override
    public Fragment getItem(int position)
    {
        return fragmentArrayList.get(position);
    }
    @Override
    public int getCount()
    {
        return fragmentArrayList.size();
    }
    public void addFragment(Fragment fragment, String title)
    {
        fragmentArrayList.add(fragment);
        fragmentTitle.add(title);
    }
    @Nullable
    @Override
    public CharSequence getPageTitle(int position)
    { return fragmentTitle.get(position); }
}

customFragment.java File

import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import androidx.fragment.app.Fragment;
public class customFragment extends Fragment {
    String displayContent,description;
    customFragment(String name,String desc)
    {
        this.displayContent = name;
        this.description = desc;
    }
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        View customView = inflater.inflate(R.layout.fragment_page1,container,false);
        ((TextView)customView.findViewById(R.id.displayContent)).setText(this.displayContent);
        ((TextView)customView.findViewById(R.id.description)).setText(this.description);
        return customView;
    }
}

MainActivity.java File

import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import androidx.appcompat.app.AppCompatActivity;
import androidx.viewpager.widget.ViewPager;
import com.google.android.material.tabs.TabLayout;
public class MainActivity extends AppCompatActivity {
    private TabLayout tabLayout;
    private ViewPager viewPager;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        tabLayout = findViewById(R.id.tablayout);
        viewPager = findViewById(R.id.viewpager);
        tabLayout.setupWithViewPager(viewPager);
        VPAdapter vpAdapter = new VPAdapter(getSupportFragmentManager());
        vpAdapter.addFragment(new customFragment("Roll number: 1133","You are on the First page."),"Page 1");
                vpAdapter.addFragment(new customFragment("Name: Dhananjay","You are on the Second page."),"Page 2");
                        vpAdapter.addFragment(new customFragment("Class: SYBSc Computer Science - A","You are on the Thirdpage."),"Page3");
                                viewPager.setAdapter(vpAdapter);
    }
}


//Practical (Create an Android App that demonstrates navigation between three Activities.)

AndroidManifest.xml File

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.twoactivity">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="First Activity"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <activity android:name=".SecondActivity"
            android:label="Second Activity"
            android:parentActivityName=".MainActivity">
            <meta-data
                android:name = "android.support.PARENT_ACTIVITY"
                android:value = ".MainActivity"></meta-data>
        </activity>
        <activity android:name=".ThirdActivity"
            android:label="Third Activity"
            android:parentActivityName=".SecondActivity">
            <meta-data
                android:name = "android.support.PARENT_ACTIVITY"
                android:value = ".SecondActivity"></meta-data>
        </activity>

    </application>
</manifest>


activity_main.xml File
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">
    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="First Activity"
        android:textSize="16sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.498"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.186" />
    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="496dp"
        android:onClick="callSecondActivity"
        android:text="CallSecondActivity"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.497"
        app:layout_constraintStart_toStartOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

activity_second.xml File

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".SecondActivity">
    <TextView
        android:id="@+id/textView2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="124dp"
        android:text="Second Activity"
        android:textSize="16sp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
    <Button
        android:id="@+id/button2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="504dp"
        android:onClick="callThirdActivity"
        android:text="CallThirdActivity"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

activity_third.xml File

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".ThirdActivity">
    <TextView
        android:id="@+id/textView3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="128dp"
        android:text="Third Activity"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.498"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
    <Button
        android:id="@+id/button3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="500dp"
        android:onClick="callFirstActivity"
        android:text="CallFirstActivity"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.497"
        app:layout_constraintStart_toStartOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>


MainActivity.java File

import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
public class MainActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }
    public void callSecondActivity(View view){
        Intent i = new
                Intent(getApplicationContext(),SecondActivity.class);
        i.putExtra("Value1","Traversed to Second Activity");
        i.putExtra("Value2","Three Activities Example");
        startActivity(i);
    }
}

SecondActivity.java File


import androidx.appcompat.app.AppCompatActivity;

import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Toast;
public class SecondActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_second);
        Bundle extras = getIntent().getExtras();
        String value1 = extras.getString("Value1");
        String value2 = extras.getString("Value2");
        Toast.makeText(this,"Value1: "+value1+"\n"+"Value2: "+value2,Toast.LENGTH_LONG).show();
    }
    public void callThirdActivity(View view){
        Intent i = new Intent(getApplicationContext(),ThirdActivity.class);
        startActivity(i);
    }
}

ThirdActivity.java File

import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
public class ThirdActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_third);
    }
    public void callFirstActivity(View view){
        Intent i = new Intent(getApplicationContext(),MainActivity.class);
        startActivity(i);
    }
}


//Practical (Database)

activity_main.xml File

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation = "vertical"
    tools:context=".MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="20dp"
        android:text="UserName" />
    <EditText
        android:id="@+id/userNameValue"
        android:textSize="20dp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="20dp"
        android:text="Password" />
    <EditText
        android:id="@+id/passwordValue"
        android:textSize="20dp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:inputType="textPassword"/>

    <Button
        android:id="@+id/button"
        android:layout_gravity="center"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="addUser"
        android:text="Add User" />
    <Button
        android:id="@+id/button2"
        android:layout_gravity="center"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="viewDetails"
        android:text="View Details" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text = "Enter Username"
        android:textSize = "20dp">
    </TextView>

    <EditText
        android:id="@+id/name"
        android:textSize="20dp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />


    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop = "10dp"
        android:text = "NewUserName to Update"
        android:textSize = "20dp">
    </TextView>

    <EditText
        android:id = "@+id/newName"
        android:layout_width = "wrap_content"
        android:layout_height= "wrap_content"
        android:textSize = "20dp">
    </EditText>

    <Button
        android:id="@+id/button4"
        android:layout_gravity="center"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="update"
        android:text="Update" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop = "10dp"
        android:text = "Delete User"
        android:textSize = "20dp">
    </TextView>

    <EditText
        android:id = "@+id/delName"
        android:layout_width = "wrap_content"
        android:layout_height= "wrap_content"
        android:textSize = "20dp">
    </EditText>

    <Button
        android:id="@+id/button5"
        android:layout_gravity="center"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="delete"
        android:text="Delete" />
</LinearLayout>



Message.java File

import android.widget.Toast;
import android.content.Context;

public class Message {
    public static void message(Context context,String message){
        Toast.makeText(context,message,Toast.LENGTH_LONG).show();
    }}




DCSDatabaseAdapter.java File

import android.database.sqlite.SQLiteOpenHelper;
import android.database.sqlite.SQLiteDatabase;
import android.database.SQLException;
import android.content.ContentValues;
import android.database.Cursor;
import android.content.Context;

public class DCSDatabaseAdapter {

    private Context context;
    private SQLiteDatabase db;
    private DCSHelper helper;
    public DCSDatabaseAdapter(Context c){
        context = c;
    }

    //Open Connection Database.
    public DCSDatabaseAdapter open() throws SQLException{
        helper = new DCSHelper(context);
        db = helper.getWritableDatabase();
        return this;
    }

    //Insert Data
    public long insertData(String name,String password){
        //SQLiteDatabase db = helper.getWritableDatabase();   //pen
        ContentValues contentValues = new ContentValues();
        contentValues.put(DCSHelper.NAME,name);
        contentValues.put(DCSHelper.PASSWORD,password);
        long id = db.insert(DCSHelper.TABLE_NAME,null,contentValues);
        //Message.message(context,""+id);
        return id;
    }

    //GetAll the Records
    public String getAllData(){
        //SQLiteDatabase db = helper.getWritableDatabase();

        String[] columns = {DCSHelper.NAME,DCSHelper.PASSWORD};
        Cursor cursor = db.query(DCSHelper.TABLE_NAME,columns,null,null,null,null,null,null);
        StringBuffer buffer = new StringBuffer();
        while(cursor.moveToNext()){
            String name = cursor.getString(0);
            String password = cursor.getString(1);
            buffer.append(name+ " " +password+ "\n");
        }
        return buffer.toString();
    }

    //Get Particular Data
    public String getData(String name){
        //SQLiteDatabase db = helper.getWritableDatabase();
        String[] columns = {DCSHelper.NAME,DCSHelper.PASSWORD};
        String uname = name;

        Cursor cursor = db.query(DCSHelper.TABLE_NAME,columns,null,null,null,null,null,null);
        StringBuffer buffer = new StringBuffer();
        while(cursor.moveToNext()){
            String naam = cursor.getString(0);
            String pass = cursor.getString(1);
            if(naam == uname){
                buffer.append(naam+ " " +pass);
                break;
            }
        }
        return buffer.toString();
    }

    //Update Names
    public int updateName(String oldName,String newName){
        //SQLiteDatabase db = helper.getWritableDatabase();
        ContentValues contentValues = new ContentValues();
        contentValues.put(DCSHelper.NAME,newName);
        String[] whereArgs = {oldName};
        int count = db.update(DCSHelper.TABLE_NAME,contentValues,DCSHelper.NAME+"=?",whereArgs);
        return count;
    }

    public int deleteRow(String name){
        //SQLiteDatabase db = helper.getWritableDatabase();
        String[] whereArgs = {name};
        int count = db.delete(DCSHelper.TABLE_NAME,DCSHelper.NAME+"=?",whereArgs);
        return count;
    }

    static class DCSHelper extends SQLiteOpenHelper{
        private static final String DATABASE_NAME = "Dcsdatabase10";
        private static final String TABLE_NAME = "DCSTABLE";
        private static final int DATABASE_VERSION = 1;
        private static final String UID = "_id";
        private static final String NAME = "Name";
        private static final String PASSWORD = "Password";
        private static final String CREATE_TABLE = "CREATE TABLE " +TABLE_NAME + "("
                + NAME + " VARCHAR(255)," +PASSWORD+ " VARCHAR(255));";
        private static final String DROP_TABLE = "DROP TABLE IF EXISTS " +TABLE_NAME+";";
        private Context context;

        public DCSHelper(Context context){
            super(context,DATABASE_NAME,null,DATABASE_VERSION);
            this.context = context;
            Message.message(context,"DCSHelper Called..");
        }

        @Override
        public void onCreate(SQLiteDatabase db){
            try{
                db.execSQL(CREATE_TABLE);
                Message.message(context,"OnCreate() Called..");
            }catch(SQLException e){
                Message.message(context,""+e);
            }
        }

        @Override
        public void onUpgrade(SQLiteDatabase db,int oldVersion,int newVersion){
            try{
                db.execSQL(DROP_TABLE);
                onCreate(db);
            }catch(SQLException e){
                Message.message(context,""+e);
            }
        }
    }
}


MainActivity.java File

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;


import androidx.appcompat.app.AppCompatActivity;
import android.widget.EditText;
import android.view.View;
import android.os.Bundle;

public class MainActivity extends AppCompatActivity {
    EditText userName,password,name,newName,delName;
    DCSDatabaseAdapter dcsHelper;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        userName = (EditText) findViewById(R.id.userNameValue);
        password = (EditText) findViewById(R.id.passwordValue);
        name = (EditText) findViewById(R.id.name);
        newName = (EditText) findViewById(R.id.newName);
        delName = (EditText) findViewById(R.id.delName);
        dcsHelper = new DCSDatabaseAdapter(this);
        dcsHelper.open();
    }

    public void addUser(View view){
        String user = userName.getText().toString();
        String pass = password.getText().toString();
        long id = dcsHelper.insertData(user,pass);
        if(id < 0){
            Message.message(this,"Unsuccessful..");
        }
        else{
            Message.message(this,"Successfull...");
        }
    }

    public void viewDetails(View view){
        String data = dcsHelper.getAllData();
        Message.message(this,data);
    }

    /*
    public void getDetails(View view){
        String s1 = name.getText().toString();
        String data = dcsHelper.getData(s1);
        Message.message(this,data);
    }*/

    public void update(View view){
        String naam = name.getText().toString();
        String nnaam = newName.getText().toString();
        dcsHelper.updateName(naam,nnaam);
    }

    public void delete(View view){
        String naam = delName.getText().toString();
        int count = dcsHelper.deleteRow(naam);
        Message.message(this,""+count);
    }
}


//Practical (Calculator)

activity_main.xml File

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity">
    <RelativeLayout
        android:id = "@+id/relativeId1"
        android:layout_width = "312dp"
        android:layout_height = "wrap_content"
        android:layout_gravity = "center"
        android:layout_marginLeft = "5dp">

        <TextView
            android:layout_width = "wrap_content"
            android:layout_height = "wrap_content"
            android:id = "@+id/textView1"
            android:layout_marginTop = "300dp"
            android:layout_marginLeft = "25dp"
            android:textSize = "30dp">
        </TextView>
        <TextView
            android:layout_width = "wrap_content"
            android:layout_height = "wrap_content"
            android:id = "@+id/textView2"
            android:layout_marginTop = "250dp"
            android:layout_marginLeft = "25dp"
            android:textSize = "20dp">
        </TextView>
        <Button
            android:id = "@+id/buttonClear"
            android:layout_width = "wrap_content"
            android:layout_height = "wrap_content"
            android:layout_alignParentLeft = "true"
            android:layout_marginTop = "350dp"
            android:padding = "20px"
            android:text = "Clear">
        </Button>
        <Button
            android:id = "@+id/buttonBack"
            android:layout_width = "wrap_content"
            android:layout_height = "wrap_content"
            android:layout_alignTop = "@+id/buttonClear"
            android:layout_toRightOf = "@+id/buttonClear"
            android:padding = "20px"
            android:text = "bk">
        </Button>
        <Button
            android:id = "@+id/buttonMod"
            android:layout_width = "wrap_content"
            android:layout_height = "wrap_content"
            android:layout_alignTop = "@+id/buttonClear"
            android:layout_toRightOf = "@+id/buttonBack"
            android:padding = "20px"
            android:text = "%">
        </Button>
        <Button
            android:id = "@+id/buttonDiv"
            android:layout_width = "wrap_content"
            android:layout_height = "wrap_content"
            android:layout_alignTop = "@+id/buttonClear"
            android:layout_toRightOf = "@+id/buttonMod"
            android:padding = "20px"
            android:text = "/">
        </Button>
        <Button
            android:id = "@+id/button7"
            android:layout_width = "wrap_content"
            android:layout_height = "wrap_content"
            android:layout_alignParentLeft = "true"
            android:layout_below = "@+id/buttonClear"
            android:padding = "20px"
            android:text = "7">
        </Button>
        <Button
            android:id = "@+id/button8"
            android:layout_width = "wrap_content"
            android:layout_height = "wrap_content"
            android:layout_alignTop = "@+id/button7"
            android:layout_toRightOf = "@+id/button7"
            android:padding = "20px"
            android:text = "8">
        </Button>
        <Button
            android:id = "@+id/button9"
            android:layout_width = "wrap_content"
            android:layout_height = "wrap_content"
            android:layout_alignTop = "@+id/button7"
            android:layout_toRightOf = "@+id/button8"
            android:padding = "20px"
            android:text = "9">
        </Button>
        <Button
            android:id = "@+id/buttonMul"
            android:layout_width = "wrap_content"
            android:layout_height = "wrap_content"
            android:layout_alignTop = "@+id/button7"
            android:layout_toRightOf = "@+id/button9"
            android:padding = "20px"
            android:text = "X">
        </Button>
        <Button
            android:id = "@+id/button4"
            android:layout_width = "wrap_content"
            android:layout_height = "wrap_content"
            android:layout_alignParentLeft = "true"
            android:layout_below = "@+id/button7"
            android:padding = "20px"
            android:text = "4">
        </Button>
        <Button
            android:id = "@+id/button5"
            android:layout_width = "wrap_content"
            android:layout_height = "wrap_content"
            android:layout_alignTop = "@+id/button4"
            android:layout_toRightOf = "@+id/button4"
            android:padding = "20px"
            android:text = "5">
        </Button>
        <Button
            android:id = "@+id/button6"
            android:layout_width = "wrap_content"
            android:layout_height = "wrap_content"
            android:layout_alignTop = "@+id/button4"
            android:layout_toRightOf = "@+id/button5"
            android:padding = "20px"
            android:text = "6">
        </Button>
        <Button
            android:id = "@+id/buttonSub"
            android:layout_width = "wrap_content"
            android:layout_height = "wrap_content"
            android:layout_alignTop = "@+id/button4"
            android:layout_toRightOf = "@+id/button6"
            android:padding = "20px"
            android:text = "-">
        </Button>
        <Button
            android:id = "@+id/button1"
            android:layout_width = "wrap_content"
            android:layout_height = "wrap_content"
            android:layout_alignParentLeft = "true"
            android:layout_below = "@+id/button4"
            android:padding = "20px"
            android:text = "1">
        </Button>
        <Button
            android:id = "@+id/button2"
            android:layout_width = "wrap_content"
            android:layout_height = "wrap_content"
            android:layout_alignTop = "@+id/button1"
            android:layout_toRightOf = "@+id/button1"
            android:padding = "20px"
            android:text = "2">
        </Button>
        <Button
            android:id = "@+id/button3"
            android:layout_width = "wrap_content"
            android:layout_height = "wrap_content"
            android:layout_alignTop = "@+id/button1"
            android:layout_toRightOf = "@+id/button2"
            android:padding = "20px"
            android:text = "3">
        </Button>
        <Button
            android:id = "@+id/buttonAdd"
            android:layout_width = "wrap_content"
            android:layout_height = "wrap_content"
            android:layout_alignTop = "@+id/button1"
            android:layout_toRightOf = "@+id/button3"
            android:padding = "20px"
            android:text = "+">
        </Button>
        <Button
            android:id = "@+id/buttonNull"
            android:layout_width = "wrap_content"
            android:layout_height = "wrap_content"
            android:layout_alignParentLeft = "true"
            android:layout_below = "@+id/button1"
            android:padding = "20px"
            android:text = "NA">
        </Button>
        <Button
            android:id = "@+id/button0"
            android:layout_width = "wrap_content"
            android:layout_height = "wrap_content"
            android:layout_alignTop = "@+id/buttonNull"
            android:layout_toRightOf = "@+id/buttonNull"
            android:padding = "20px"
            android:text = "0">
        </Button>
        <Button
            android:id = "@+id/buttonDot"
            android:layout_width = "wrap_content"
            android:layout_height = "wrap_content"
            android:layout_alignTop = "@+id/buttonNull"
            android:layout_toRightOf = "@+id/button0"
            android:padding = "20px"
            android:text = ".">
        </Button>
        <Button
            android:id = "@+id/buttonAns"
            android:layout_width = "wrap_content"
            android:layout_height = "wrap_content"
            android:layout_alignTop = "@+id/buttonNull"
            android:layout_toRightOf = "@+id/buttonDot"
            android:padding = "20px"
            android:text = "=">
        </Button>
    </RelativeLayout>
</LinearLayout>


MainActivity.java File

import androidx.appcompat.app.AppCompatActivity;
import android.widget.TextView;
import android.widget.Button;
import android.view.View;
import android.os.Bundle;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
    private TextView tv1,tv2;
    private boolean ans=true;
    private Integer b,dotHelp=1,ansPress=1;
    private double num1,num2,result;
    private String a = "",aa ="";
    private Button
            b1,b2,b3,b4,b5,b6,b7,b8,b9,b0,bDot,bAns,bAdd,bSub,bMul,bDiv,bMod,bBack,
            bClear;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        tv1 = (TextView) findViewById(R.id.textView1);
        tv2 = (TextView) findViewById(R.id.textView2);
        b1 = (Button) findViewById(R.id.button1);
        b2 = (Button) findViewById(R.id.button2);
        b3 = (Button) findViewById(R.id.button3);
        b4 = (Button) findViewById(R.id.button4);
        b5 = (Button) findViewById(R.id.button5);
        b6 = (Button) findViewById(R.id.button6);
        b7 = (Button) findViewById(R.id.button7);
        b8 = (Button) findViewById(R.id.button8);
        b9 = (Button) findViewById(R.id.button9);
        b0 = (Button) findViewById(R.id.button0);
        bDot = (Button) findViewById(R.id.buttonDot);
        bAns = (Button) findViewById(R.id.buttonAns);
        bAdd = (Button) findViewById(R.id.buttonAdd);
        bSub = (Button) findViewById(R.id.buttonSub);
        bMul = (Button) findViewById(R.id.buttonMul);
        bMod = (Button) findViewById(R.id.buttonMod);
        bDiv = (Button) findViewById(R.id.buttonDiv);
        bClear = (Button) findViewById(R.id.buttonClear);
        b1.setOnClickListener(new View.OnClickListener(){
            public void onClick(View view)
            {
                a = tv1.getText().toString();
                a = a + "1";
                tv1.setText(a);
            }
        });
        b2.setOnClickListener(new View.OnClickListener(){
            public void onClick(View view)
            {
                a = tv1.getText().toString();
                a = a + "2";
                tv1.setText(a);
            }
        });
        b3.setOnClickListener(new View.OnClickListener(){
            public void onClick(View view)
            {
                a = tv1.getText().toString();
                a = a + "3";
                tv1.setText(a);
            }
        });
        b4.setOnClickListener(new View.OnClickListener(){
            public void onClick(View view)
            {
                a = tv1.getText().toString();
                a = a + "4";
                tv1.setText(a);
            }
        });
        b5.setOnClickListener(new View.OnClickListener(){
            public void onClick(View view)
            {
                a = tv1.getText().toString();
                a = a + "5";
                tv1.setText(a);
            }
        });
        b6.setOnClickListener(new View.OnClickListener(){
            public void onClick(View view)
            {
                a = tv1.getText().toString();
                a = a + "6";
                tv1.setText(a);
            }
        });
        b7.setOnClickListener(new View.OnClickListener(){
            public void onClick(View view)
            {
                a = tv1.getText().toString();
                a = a + "7";
                tv1.setText(a);
            }
        });
        b8.setOnClickListener(new View.OnClickListener(){
            public void onClick(View view)
            {
                a = tv1.getText().toString();
                a = a + "8";
                tv1.setText(a);
            }
        });
        b9.setOnClickListener(new View.OnClickListener(){
            public void onClick(View view)
            {
                a = tv1.getText().toString();
                a = a + "9";
                tv1.setText(a);
            }
        });
        b0.setOnClickListener(new View.OnClickListener(){
            public void onClick(View view)
            {
                a = tv1.getText().toString();
                a = a + "0";
                tv1.setText(a);
            }
        });
        bAdd.setOnClickListener(new View.OnClickListener(){
            public void onClick(View view)
            {
                aa = a;
                b = 1;
                a = "";
                dotHelp=1;
                if(a=="" && aa=="")
                {
                    tv2.setText("");
                    tv1.setText("");
                }
                else
                {
                    tv2.setText(aa+ "+");
                    tv1.setText("");
                }
            }
        });
        bSub.setOnClickListener(new View.OnClickListener(){
            public void onClick(View view)
            {
                aa = a;
                b = 2;
                a = "";
                dotHelp=1;
                if(a=="" && aa=="") {
                    tv1.setText("");
                    tv2.setText("");
                }
                else
                {
                    tv2.setText(aa+ "-");
                    tv1.setText("");
                }
            }
        });
        bMul.setOnClickListener(new View.OnClickListener(){
            public void onClick(View view)
            {
                aa = a;
                b = 3;
                a = "";
                dotHelp=1;
                if(a=="" && aa=="") {
                    tv1.setText("");
                    tv2.setText("");
                }
                else
                {
                    tv2.setText(aa+ "*");
                    tv1.setText("");
                }
            }
        });
        bDiv.setOnClickListener(new View.OnClickListener(){
            public void onClick(View view)
            {
                aa = a;
                b = 4;
                a = "";
                dotHelp=1;
                if(a=="" && aa=="") {
                    tv1.setText("");
                    tv2.setText("");
                }
                else
                {
                    tv2.setText(aa+ "/");
                    tv1.setText("");
                }
            }
        });
        bMod.setOnClickListener(new View.OnClickListener(){
            public void onClick(View view)
            {
                aa = a;
                b = 5;
                a = "";
                dotHelp=1;
                if(a=="" && aa=="") {
                    tv1.setText("");
                    tv2.setText("");
                }
                else
                {
                    tv2.setText(aa+ "%");
                    tv1.setText("");
                }
            }
        });
        bDot.setOnClickListener(new View.OnClickListener(){
            public void onClick(View view)
            {
                if(dotHelp==1){
                    a = tv1.getText().toString();
                    a = a + ".";
                    tv1.setText(a);
                }
                else{
                    a = tv1.getText().toString();
                    a = a + "";
                    tv1.setText(a);
                }
                dotHelp++;
            }
        });
        bAns.setOnClickListener(new View.OnClickListener(){
            public void onClick(View view)
            {
                String op="";
                if(ansPress == 1)
                {
                    if(b==1)
                    {
                        try {
                            num1 = Double.parseDouble(aa);
                            num2 = Double.parseDouble(a);
                            result = num1 + num2;
                        }catch(Exception e){
                            ans = false;
                        };
                        aa = "";
                        a = "";
                        op = "+";
                    }
                    else if(b==2)
                    {
                        try {
                            num1 = Double.parseDouble(aa);
                            num2 = Double.parseDouble(a);
                            result = num1 - num2;
                        }catch(Exception e)
                        {
                            ans = false;
                        }
                        aa = "";
                        a = "";
                        op = "-";
                    }
                    else if(b==3)
                    {
                        try {
                            num1 = Double.parseDouble(aa);
                            num2 = Double.parseDouble(a);
                            result = num1 * num2;
                        }catch(Exception e){
                            ans = false;
                        }
                        aa = "";
                        a = "";
                        op = "*";
                    }
                    else if(b==4)
                    {
                        num1 = Double.parseDouble(aa);
                        num2 = Double.parseDouble(a);
                        aa = "";
                        a = "";
                        op = "/";
                        try{
                            result = num1/num2;
                        }catch(Exception e)
                        {
                            ans = false;
                        }
                    }
                    else if(b==5)
                    {
                        num1 = Double.parseDouble(aa);
                        num2 = Double.parseDouble(a);
                        op = "%";
                        try{
                            result = num1%num2;
                        }catch(Exception e)
                        {
                            ans = false;
                        }
                    }
                    ansPress++;
                }
                else
                {
                    tv1.setText(Double.toString(result));
                }
                if(ans)
                {
                    tv2.setText(num1 + op + num2);
                    tv1.setText(Double.toString(result));
                    String ans = num1 + op + num2 + " = " +result;

                    Toast.makeText(MainActivity.this,ans,Toast.LENGTH_LONG).show();
                }
                else
                {
                    tv2.setText(num1 + op + num2);
                    tv1.setText("Invalid Expression!!");
                    ans = true;
                }
            }
        });
        bClear.setOnClickListener(new View.OnClickListener(){
            public void onClick(View view)
            {
                tv1.setText("");
                tv2.setText("");
                dotHelp=1;
                ansPress=1;
            }
        });
    }
}


//Practical (Create SYBSC database in SQLite. Create table SYCS with following columns
ROLLNO  int
Name        varchar(100)
Insert 3 records in it.)

activity_main.xml File

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation = "vertical"
    tools:context=".MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="20dp"
        android:text="Name" />
    <EditText
        android:id="@+id/userNameValue"
        android:textSize="20dp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="20dp"
        android:text="ROLLNO" />
    <EditText
        android:id="@+id/passwordValue"
        android:textSize="20dp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:inputType="textPassword"/>

    <Button
        android:id="@+id/button"
        android:layout_gravity="center"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="addUser"
        android:text="Add User" />
    <Button
        android:id="@+id/button2"
        android:layout_gravity="center"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="viewDetails"
        android:text="View Details" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text = "Enter Name to Update"
        android:textSize = "20dp">
    </TextView>

    <EditText
        android:id="@+id/name"
        android:textSize="20dp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />


    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop = "10dp"
        android:text = "New Name to Update"
        android:textSize = "20dp">
    </TextView>

    <EditText
        android:id = "@+id/newName"
        android:layout_width = "wrap_content"
        android:layout_height= "wrap_content"
        android:textSize = "20dp">
    </EditText>

    <Button
        android:id="@+id/button4"
        android:layout_gravity="center"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="update"
        android:text="Update" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop = "10dp"
        android:text = "Delete User"
        android:textSize = "20dp">
    </TextView>

    <EditText
        android:id = "@+id/delName"
        android:layout_width = "wrap_content"
        android:layout_height= "wrap_content"
        android:textSize = "20dp">
    </EditText>

    <Button
        android:id="@+id/button5"
        android:layout_gravity="center"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="delete"
        android:text="Delete" />
</LinearLayout>

Message.java File

package com.example.database;

import android.widget.Toast;
import android.content.Context;

public class Message {
    public static void message(Context context,String message){
        Toast.makeText(context,message,Toast.LENGTH_LONG).show();
    }}


DCSDatabaseAdapter.java File

package com.example.database;

import android.database.sqlite.SQLiteOpenHelper;
import android.database.sqlite.SQLiteDatabase;
import android.database.SQLException;
import android.content.ContentValues;
import android.database.Cursor;
import android.content.Context;

public class DCSDatabaseAdapter {

    private Context context;
    private SQLiteDatabase db;
    private DCSHelper helper;
    public DCSDatabaseAdapter(Context c){
        context = c;
    }

    //Open Connection Database.
    public DCSDatabaseAdapter open() throws SQLException{
        helper = new DCSHelper(context);
        db = helper.getWritableDatabase();
        return this;
    }

    //Insert Data
    public long insertData(String name,String password){
        //SQLiteDatabase db = helper.getWritableDatabase();   //pen
        ContentValues contentValues = new ContentValues();
        contentValues.put(DCSHelper.NAME,name);
        contentValues.put(DCSHelper.ROLL,password);
        long id = db.insert(DCSHelper.TABLE_NAME,null,contentValues);
        //Message.message(context,""+id);
        return id;
    }

    //GetAll the Records
    public String getAllData(){
        //SQLiteDatabase db = helper.getWritableDatabase();

        String[] columns = {DCSHelper.NAME,DCSHelper.ROLL};
        Cursor cursor = db.query(DCSHelper.TABLE_NAME,columns,null,null,null,null,null,null);
        StringBuffer buffer = new StringBuffer();
        while(cursor.moveToNext()){
            String name = cursor.getString(0);
            String password = cursor.getString(1);
            buffer.append(name+ " " +password+ "\n");
        }
        return buffer.toString();
    }

    //Get Particular Data
    public String getData(String name){
        //SQLiteDatabase db = helper.getWritableDatabase();
        String[] columns = {DCSHelper.NAME,DCSHelper.ROLL};
        String uname = name;

        Cursor cursor = db.query(DCSHelper.TABLE_NAME,columns,null,null,null,null,null,null);
        StringBuffer buffer = new StringBuffer();
        while(cursor.moveToNext()){
            String naam = cursor.getString(0);
            String pass = cursor.getString(1);
            if(naam == uname){
                buffer.append(naam+ " " +pass);
                break;
            }
        }
        return buffer.toString();
    }

    //Update Names
    public int updateName(String oldName,String newName){
        //SQLiteDatabase db = helper.getWritableDatabase();
        ContentValues contentValues = new ContentValues();
        contentValues.put(DCSHelper.NAME,newName);
        String[] whereArgs = {oldName};
        int count = db.update(DCSHelper.TABLE_NAME,contentValues,DCSHelper.NAME+"=?",whereArgs);
        return count;
    }

    public int deleteRow(String name){
        //SQLiteDatabase db = helper.getWritableDatabase();
        String[] whereArgs = {name};
        int count = db.delete(DCSHelper.TABLE_NAME,DCSHelper.NAME+"=?",whereArgs);
        return count;
    }

    static class DCSHelper extends SQLiteOpenHelper{
        private static final String DATABASE_NAME = "SYCS";
        private static final String TABLE_NAME = "STUDENTTABLE";
        private static final int DATABASE_VERSION = 1;
        private static final String UID = "_id";
        private static final String NAME = "Name";
        private static final String ROLL = "ROllno";
        private static final String CREATE_TABLE = "CREATE TABLE " +TABLE_NAME + "("
                + NAME + " VARCHAR(255)," +ROLL+ " INT(255));";
        private static final String DROP_TABLE = "DROP TABLE IF EXISTS " +TABLE_NAME+";";
        private Context context;

        public DCSHelper(Context context){
            super(context,DATABASE_NAME,null,DATABASE_VERSION);
            this.context = context;
            Message.message(context,"DCSHelper Called..");
        }

        @Override
        public void onCreate(SQLiteDatabase db){
            try{
                db.execSQL(CREATE_TABLE);
                Message.message(context,"OnCreate() Called..");
            }catch(SQLException e){
                Message.message(context,""+e);
            }
        }

        @Override
        public void onUpgrade(SQLiteDatabase db,int oldVersion,int newVersion){
            try{
                db.execSQL(DROP_TABLE);
                onCreate(db);
            }catch(SQLException e){
                Message.message(context,""+e);
            }
        }
    }
}


MainActivity.java File

package com.example.database;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;


import androidx.appcompat.app.AppCompatActivity;
import android.widget.EditText;
import android.view.View;
import android.os.Bundle;

public class MainActivity extends AppCompatActivity {
    EditText userName,password,name,newName,delName;
    DCSDatabaseAdapter dcsHelper;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        userName = (EditText) findViewById(R.id.userNameValue);
        password = (EditText) findViewById(R.id.passwordValue);
        name = (EditText) findViewById(R.id.name);
        newName = (EditText) findViewById(R.id.newName);
        delName = (EditText) findViewById(R.id.delName);
        dcsHelper = new DCSDatabaseAdapter(this);
        dcsHelper.open();
    }

    public void addUser(View view){
        String user = userName.getText().toString();
        String pass = password.getText().toString();
        long id = dcsHelper.insertData(user,pass);
        if(id < 0){
            Message.message(this,"Unsuccessful..");
        }
        else{
            Message.message(this,"Successfull...");
        }
    }

    public void viewDetails(View view){
        String data = dcsHelper.getAllData();
        Message.message(this,data);
    }

    /*
    public void getDetails(View view){
        String s1 = name.getText().toString();
        String data = dcsHelper.getData(s1);
        Message.message(this,data);
    }*/

    public void update(View view){
        String naam = name.getText().toString();
        String nnaam = newName.getText().toString();
        dcsHelper.updateName(naam,nnaam);
    }

    public void delete(View view){
        String naam = delName.getText().toString();
        int count = dcsHelper.deleteRow(naam);
        Message.message(this,"Deleted "+naam);
    }
}


//Practical (Notification & Alert)

activity_main.xml File

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/button_show_notification"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="123dp"
        android:layout_marginLeft="123dp"
        android:layout_marginTop="341dp"
        android:layout_marginEnd="124dp"
        android:layout_marginRight="124dp"
        android:layout_marginBottom="342dp"
        android:text="Notification Demo"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>


MainActivity.java File

package com.example.notificationdemo;

import androidx.annotation.RequiresApi;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.NotificationCompat;
import androidx.core.app.NotificationManagerCompat;
import android.app.AlarmManager;
import android.app.NotificationChannel;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.content.Intent;
import android.os.Build;
import android.os.Bundle;


public class MainActivity extends AppCompatActivity {
    @RequiresApi(api = Build.VERSION_CODES.O)
    @Override
    protected void onCreate(Bundle xyz) {
        super.onCreate(xyz);
        setContentView(R.layout.activity_main);
        Intent i = new Intent(this,MainActivity.class);
        PendingIntent pendingIntent = PendingIntent.getBroadcast(getApplicationContext(), 234324243, i, PendingIntent.FLAG_UPDATE_CURRENT);
        AlarmManager am = (AlarmManager) getSystemService(ALARM_SERVICE);
        am.set(AlarmManager.RTC_WAKEUP, System.currentTimeMillis() + 5000, pendingIntent);
        //Toast.makeText(this,"huehue",Toast.LENGTH_LONG).show();
        NotificationChannel channel = new NotificationChannel("My Notification","My Notification", NotificationManager.IMPORTANCE_DEFAULT);
        NotificationManager manager = getSystemService(NotificationManager.class);
        manager.createNotificationChannel(channel);
        NotificationCompat.Builder builder = new NotificationCompat.Builder(this, "My Notification");
        builder.setContentTitle("Alert!!");
        builder.setContentText("Startup notification..");
        builder.setSmallIcon(R.drawable.ic_launcher_background);
        builder.setAutoCancel(false);
        NotificationManagerCompat compatManager = NotificationManagerCompat.from(this);
        compatManager.notify(1, builder.build());
    }
}




//Practical (Two Activity) Explicit Intent Pucha tho Two activity ya Three Activity vala code kr dena

activity_main.xml file

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation = "vertical"
    tools:context=".MainActivity">

    <EditText
        android:hint="Enter Your Name"
        android:id="@+id/editText1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:layout_marginTop="100dp">
    </EditText>

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:text="Submit to Second Activity"
        android:layout_margin="30dp">
    </Button>

</LinearLayout>


activity_second.xml file

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation = "vertical"
    tools:context=".SecondActivity">

    <TextView
        android:layout_width = "wrap_content"
        android:layout_height = "wrap_content"
        android:id = "@+id/textView1"
        android:layout_gravity = "center"
        android:textSize = "30sp"
        android:layout_marginTop = "250dp">
    </TextView>
</LinearLayout>


AndroidManifest.xml file

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.twoactivity">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="First Activity (1108 Arpit)"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <activity android:name=".SecondActivity"
            android:label="Second Activity (1108 Arpit)"
            android:parentActivityName=".MainActivity">
            <meta-data
                android:name = "android.support.PARENT_ACTIVITY"
                android:value = ".MainActivity"></meta-data>
        </activity>
    </application>
</manifest>


MainActivity.java file

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.widget.EditText;
import android.widget.Button;
import android.widget.TextView;
import android.view.View;
import android.os.Bundle;

public class MainActivity extends AppCompatActivity {

    private EditText ed1;
    private TextView tv1;
    private Button b1;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        ed1 = (EditText) findViewById(R.id.editText1);
        b1 = (Button) findViewById(R.id.button1);
        tv1 = (TextView) findViewById(R.id.textView1);

        b1.setOnClickListener(new View.OnClickListener()
        {
            public void onClick(View view)
            {
                Intent i = new Intent(getApplicationContext(),SecondActivity.class);
                String s;
                s = ed1.getText().toString();
                i.putExtra("Name",s);
                startActivity(i);
            }
        });
    }
}

SecondActivity.java file

import androidx.appcompat.app.AppCompatActivity;
import android.widget.TextView;
import android.os.Bundle;

public class SecondActivity extends AppCompatActivity {

    private TextView tv1;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_second);

        tv1 = (TextView) findViewById(R.id.textView1);

        Bundle b = getIntent().getExtras();
        String result = b.getString("Name");

        tv1.setText("Nice meeting you "+result);
    }
}


//Practical (Create an Android app to display list of friends’ name with their photo.)

activity_main.xml File

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity"
    tools:ignore="ExtraText">

    <ListView
        android:id="@+id/simpleListView"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:divider="@color/material_blue_grey_800"
        android:dividerHeight="1dp"
        android:footerDividersEnabled="false" />
</LinearLayout>

listview.xml File

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <ImageView
        android:id="@+id/icon"
        android:layout_width="120dp"
        android:layout_height="123dp"
        android:src="@drawable/ic_launcher_foreground" />

    <TextView
        android:id="@+id/textView"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:padding="10dp" />
</LinearLayout>


CustomAdapter.java File

package com.example.listview;

import android.content.Context;
import android.media.Image;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;
import java.util.zip.Inflater;

public class CustomAdapter extends BaseAdapter {
    Context context;
    String countryList[];
    int flags[];
    LayoutInflater inflater;

    public CustomAdapter(Context applicationContext, String[] countryList, int[] flags) {
        this.context = context;
        this.countryList = countryList;
        this.flags = flags;
        inflater = (LayoutInflater.from(applicationContext));
    }
    @Override
    public int getCount() {
        return countryList.length;
    }

    @Override
    public Object getItem(int i) {
        return null;
    }

    @Override
    public long getItemId(int i) {
        return 0;
    }

    @Override
    public View getView(int i,View view,ViewGroup viewGroup) {
        view = inflater.inflate(R.layout.listview,null);
        TextView country = (TextView) view.findViewById(R.id.textView);
        ImageView icon = (ImageView) view.findViewById(R.id.icon);
        country.setText(countryList[i]);
        icon.setImageResource(flags[i]);
        return view;
    }}

MainActivity.java File

package com.example.listview;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;

import androidx.appcompat.app.AppCompatActivity;

import android.app.Activity;
import android.os.Bundle;
import android.widget.ArrayAdapter;
import android.widget.ListView;


public class MainActivity extends Activity {
    // Array of strings...
    ListView simpleList;
    String countryList[] = {"Rakesh", "Mukesh", "Kamlesh"};

    int flags[] = {R.drawable.rakesh,R.drawable.mukesh,R.drawable.kamlesh};


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        simpleList = (ListView) findViewById(R.id.simpleListView);
        CustomAdapter customAdapter = new CustomAdapter(getApplicationContext(),countryList,flags);
//      ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(this, R.layout.listview, R.id.textView, countryList);
        simpleList.setAdapter(customAdapter);
    }
}


//Practical (Popup Menu)

activity_main.xml File

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="PopupMenu"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.472" />
</androidx.constraintlayout.widget.ConstraintLayout>


popup_menu.xml File (create in menu folder in res and create this file)

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">

    <item
        android:id="@+id/upload"
        android:title="Upload"/>
    <item
        android:id="@+id/copy"
        android:title="Copy"/>
    <item
        android:id="@+id/print"
        android:title="Print"/>
    <item
        android:id="@+id/paste"
        android:title="Paste"/>
</menu>

MainActivity.java File

package com.example.popup;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.PopupMenu;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        final Button btn = (Button)findViewById(R.id.button);
        btn.setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View v){
                // Creating Instance of Popup menu
                PopupMenu popup = new PopupMenu(MainActivity.this,btn);
                //Inflating the Popup using xml file
                popup.getMenuInflater().inflate(R.menu.popup_menu,popup.getMenu());
                //registering popup with OnMenuItemClickListener
                popup.setOnMenuItemClickListener(new PopupMenu.OnMenuItemClickListener(){
                    public boolean onMenuItemClick(MenuItem item){
                        Toast.makeText(MainActivity.this,"Selected Item is: "+item.getTitle(),Toast.LENGTH_SHORT).show();
                        switch(item.getItemId()){
                            case R.id.upload:
                                return true;
                            case R.id.copy:
                                return true;
                            case R.id.print:
                                return true;
                            case R.id.paste:
                                return true;
                            default:
                                return false;
                        }
                    }
                });
                popup.show();
            }
        });
    }
}


//Practical (Develop a form to accept your name, mobile no. When click on submit button display values in toast as well as display values in second activity.   )

activity_main.xml File

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/tv"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Name:"
        android:textSize="16sp"
        android:textStyle="bold"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.131"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.169" />

    <EditText
        android:id="@+id/editTextTextPersonName"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginEnd="64dp"
        android:ems="10"
        android:inputType="textPersonName"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.151" />

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Mobile No:"
        android:textSize="16sp"
        android:textStyle="bold"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.144"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.282" />

    <EditText
        android:id="@+id/editTextTextPersonName2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:ems="10"
        android:inputType="phone"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.781"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.268" />

    <Button
        android:id="@+id/button2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Submit"
        android:onClick="show"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.407" />

</androidx.constraintlayout.widget.ConstraintLayout>


activity_second.xml File

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".SecondActivity">

    <TextView
        android:id="@+id/textView2"
        android:layout_width="191dp"
        android:layout_height="136dp"
        android:text=""
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.381" />
</androidx.constraintlayout.widget.ConstraintLayout>


MainActivity.java File

package com.example.formtwoactivity;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
    TextView tv1,tv2;
    EditText et1,et2;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        tv1 = (TextView)findViewById(R.id.tv);
        et1 = (EditText)findViewById(R.id.editTextTextPersonName);
        tv2 = (TextView)findViewById(R.id.textView);
        et2 = (EditText)findViewById(R.id.editTextTextPersonName2);
    }
    public void show(View view){
        String name,mobile;
        name = et1.getText().toString();
        mobile = et2.getText().toString();
        Toast.makeText(this,"Employee Information: \n"+name+"\n"+mobile,Toast.LENGTH_SHORT).show();
        Intent i = new Intent(getApplicationContext(),SecondActivity.class);
        i.putExtra("me",name);
        i.putExtra("you",mobile);
        startActivity(i);
    }
}


SecondActivity.java File
package com.example.formtwoactivity;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.widget.TextView;

public class SecondActivity extends AppCompatActivity {
    TextView tv1;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_second);
        Bundle extra = getIntent().getExtras();
        String un = extra.getString("me");
        String m = extra.getString("you");
        String print = "Employee Details: \n"+un+"\n"+m;
        tv1 = (TextView)findViewById(R.id.textView2);
        tv1.setText(print);

    }
}

AndroidManifest.xml File

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.formtwoactivity">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity android:name=".SecondActivity"
            android:label="Second Activity"
            android:parentActivityName=".MainActivity">
            <meta-data
                android:name = "android.support.PARENT_ACTIVITY"
                android:value = ".MainActivity"></meta-data>
        </activity>
    </application>

</manifest>







//Edit Text
import android.graphics.Color;
import android.graphics.Typeface;
import android.os.Bundle;
import android.view.Gravity;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
    EditText et;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        et = (EditText)findViewById(R.id.editTextTextPersonName);
    }
    public void show(View view){
        /*String user;
        user = et.getText().toString();

        Toast toast = new Toast(getApplicationContext());
        toast.setGravity(Gravity.CENTER,0,0);

        EditText et1 = new EditText(MainActivity.this);
        et1.setTextColor(Color.RED);

        Typeface tf = Typeface.create("default",Typeface.BOLD);
        et1.setTypeface(tf);
        et1.setText(user);
        toast.setView(et1);
        toast.show();*/
        Toast.makeText(this,"Image button is clicked",Toast.LENGTH_SHORT).show();
    }
}


//Practical (Implicit Activity)

AmndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.implicitintentapplication">

    <uses-permission android:name="android.permission.INTERNET" />

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">

        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>


activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/LaunchMap"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:layout_alignParentRight="true"
        android:layout_marginTop="100dp"
        android:layout_marginBottom="4dp"
        android:background="#ffee00"
        android:onClick="process"
        android:text="Launch Map" />

    <Button
        android:id="@+id/LaunchMarket"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/LaunchMap"
        android:layout_alignParentLeft="true"
        android:layout_alignParentRight="true"
        android:layout_marginTop="4dp"
        android:layout_marginBottom="4dp"
        android:background="#ffee00"
        android:onClick="process"
        android:text="Launch Market" />

    <Button
        android:id="@+id/SendEmail"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/LaunchMarket"
        android:layout_alignParentLeft="true"
        android:layout_alignParentRight="true"
        android:layout_marginTop="4dp"
        android:layout_marginBottom="4dp"
        android:background="#ffee00"
        android:onClick="process"
        android:text="Send Email" />

</RelativeLayout>


MainActivity.java

package com.example.implicitintentapplication;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.view.View;

public class MainActivity extends AppCompatActivity {

    //geo:19.2060, 72.8746
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    public void process(View view) {
        Intent intent = null, chooser = null;

        if (view.getId() == R.id.LaunchMap) {
            intent = new Intent(android.content.Intent.ACTION_VIEW);
            intent.setData(Uri.parse("geo:19.2060, 72.8746"));
            chooser = Intent.createChooser(intent, "Launch Map:");
            startActivity(chooser);
        }

        if (view.getId() == R.id.LaunchMarket) {
            intent = new Intent(android.content.Intent.ACTION_VIEW);
            intent.setData(Uri.parse("market://details?id=dolphin.developers.com"));
            chooser = Intent.createChooser(intent, "Launch Market:");
            startActivity(chooser);
        }

        if (view.getId() == R.id.SendEmail) {
            intent = new Intent(android.content.Intent.ACTION_SEND);
            intent.setData(Uri.parse("mailto:"));
            String[] to = {"tcsc101@gmail.com", "gishawork@gmail.com"};
            intent.putExtra(Intent.EXTRA_EMAIL, to);
            intent.putExtra(Intent.EXTRA_SUBJECT, "Greetings");
            intent.putExtra(Intent.EXTRA_TEXT, "Hi! How are you?");
            intent.setType("message/rfc822");
            chooser = Intent.createChooser(intent, "Send Email:");
            startActivity(chooser);
        }
    }
}