School, class work 05.11.2017

activity_main.xml
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<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/llyBack"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    xmlns:android="http://schemas.android.com/apk/res/android" >

    <TextView
        android:id="@+id/tvHello"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="@color/colorAccent"
        android:gravity="center"
        android:text="Hello"
        android:textSize="32sp" />

    <EditText
        android:id="@+id/etName"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_margin="16dp"
        android:hint="Enter your name"
        android:textSize="26sp" />

    <Button
        android:id="@+id/btClick"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_margin="16dp"
        android:text="Click Here"
        android:textSize="24sp" />
</LinearLayout>

MainActivity.java
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package com.example.mohamadpc.myapplication;

import android.app.Activity;
import android.graphics.Color;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.LinearLayout;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends Activity implements View.OnClickListener {
    LinearLayout llyBack;
    TextView tvHello;
    EditText etName;
    Button btClick;

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

        llyBack = findViewById(R.id.llyBack);
        tvHello = findViewById(R.id.tvHello);
        etName = findViewById(R.id.etName);
        btClick = findViewById(R.id.btClick);

        llyBack.setBackgroundColor(Color.GREEN);
        tvHello.setText("Go Home");
        btClick.setText("Login");
        btClick.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        Toast.makeText(this, "Welcome " + etName.getText(), Toast.LENGTH_LONG).show();
    }
}