School, Game 15 numbers, 15.04.18+22.04.18+06.05.18

activity_main.xml
-----------------
<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">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <Button
            android:id="@+id/btnNew"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="New"
            android:textSize="30sp" />

        <TextView
            android:id="@+id/tvCounter"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:gravity="center"
            android:text="MyText"
            android:textSize="30sp"
            tools:background="@android:color/holo_blue_bright" />

        <Button
            android:id="@+id/btnSave"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Save"
            android:textSize="30sp" />
    </LinearLayout>

    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_weight="1"
        android:orientation="horizontal">

        <Button
            android:id="@+id/btn1"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_weight="1"
            android:text="B1"
            android:textSize="40sp" />

        <Button
            android:id="@+id/btn2"
            android:layout_width="match_parent"

            android:layout_height="match_parent"
            android:layout_weight="1"
            android:text="B2"

            android:textSize="40sp" />

        <Button
            android:id="@+id/btn3"
            android:layout_width="match_parent"

            android:layout_height="match_parent"
            android:layout_weight="1"
            android:text="B3"

            android:textSize="40sp" />

        <Button
            android:id="@+id/btn4"
            android:layout_width="match_parent"

            android:layout_height="match_parent"
            android:layout_weight="1"
            android:text="B4"

            android:textSize="40sp" />
    </LinearLayout>

    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_weight="1"
        android:orientation="horizontal">

        <Button
            android:id="@+id/btn5"
            android:layout_width="match_parent"

            android:layout_height="match_parent"
            android:layout_weight="1"
            android:text="B1"
            android:textSize="40sp" />

        <Button
            android:id="@+id/btn6"
            android:layout_width="match_parent"

            android:layout_height="match_parent"
            android:layout_weight="1"
            android:text="B2"

            android:textSize="40sp" />

        <Button
            android:id="@+id/btn7"
            android:layout_width="match_parent"

            android:layout_height="match_parent"
            android:layout_weight="1"
            android:text="B3"

            android:textSize="40sp" />

        <Button
            android:id="@+id/btn8"
            android:layout_width="match_parent"

            android:layout_height="match_parent"
            android:layout_weight="1"
            android:text="B4"

            android:textSize="40sp" />
    </LinearLayout>

    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_weight="1"
        android:orientation="horizontal">

        <Button
            android:id="@+id/btn9"
            android:layout_width="match_parent"

            android:layout_height="match_parent"
            android:layout_weight="1"
            android:text="B1"
            android:textSize="40sp" />

        <Button
            android:id="@+id/btn10"
            android:layout_width="match_parent"

            android:layout_height="match_parent"
            android:layout_weight="1"
            android:text="B2"

            android:textSize="40sp" />

        <Button
            android:id="@+id/btn11"
            android:layout_width="match_parent"

            android:layout_height="match_parent"
            android:layout_weight="1"
            android:text="B3"

            android:textSize="40sp" />

        <Button
            android:id="@+id/btn12"
            android:layout_width="match_parent"

            android:layout_height="match_parent"
            android:layout_weight="1"
            android:text="B4"

            android:textSize="40sp" />
    </LinearLayout>

    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_weight="1"
        android:orientation="horizontal">

        <Button
            android:id="@+id/btn13"
            android:layout_width="match_parent"

            android:layout_height="match_parent"
            android:layout_weight="1"
            android:text="B1"
            android:textSize="40sp" />

        <Button
            android:id="@+id/btn14"
            android:layout_width="match_parent"

            android:layout_height="match_parent"
            android:layout_weight="1"
            android:text="B2"

            android:textSize="40sp" />

        <Button
            android:id="@+id/btn15"
            android:layout_width="match_parent"

            android:layout_height="match_parent"
            android:layout_weight="1"
            android:text="B3"

            android:textSize="40sp" />

        <Button
            android:id="@+id/btn16"
            android:layout_width="match_parent"

            android:layout_height="match_parent"
            android:layout_weight="1"
            android:text="B4"

            android:textSize="40sp" />
    </LinearLayout>

</LinearLayout>


MainActivity.java
-----------------
package com.example.mohamadpc.mygame;

import android.content.Context;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

import java.util.Random;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {
    Button[] myBtn;
    TextView tvCounter;
    int emptyIndex;
    int counter;

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

        tvCounter = findViewById(R.id.tvCounter);


        myBtn = new Button[16];
        for (int i = 0; i < 16; i++) {
            String btnName = "btn" + (i + 1);
            int btnId = getResources().getIdentifier(btnName, "id", getPackageName());
            myBtn[i] = findViewById(btnId);
            myBtn[i].setOnClickListener(this);
        }

        if (loadGame() == false) {
            Toast.makeText(this, "New Game", Toast.LENGTH_LONG).show();
            newGame();
        }

        findViewById(R.id.btnSave).setOnClickListener(this);
        findViewById(R.id.btnNew).setOnClickListener(this);

    }

    private void shuffle(int n) {
        Random rnd = new Random();

        for (int i = 0; i < n; i++) {
            int b1 = rnd.nextInt(16);
            int b2 = rnd.nextInt(16);

            String text = myBtn[b1].getText().toString();
            myBtn[b1].setText(myBtn[b2].getText().toString());
            myBtn[b2].setText(text);

            if (b1 == emptyIndex) {
                emptyIndex = b2;
            } else if (b2 == emptyIndex) {
                emptyIndex = b1;
            }
        }
    }

    private boolean gameIsOver() {
        for (int i = 0; i < 15; i++) {
            if (!myBtn[i].getText().toString().equals(i + 1 + "")) {
                return false;
            }
        }

        return true;
    }

    @Override
    public void onClick(View v) {
        if (v.getId() == R.id.btnSave) {
            //save the game
            saveGame();
        } else if (v.getId() == R.id.btnNew) {
            newGame();
        } else {
            int btnIndex = getButtonIndex(v.getId());
            if (canMove(btnIndex, emptyIndex)) {
                String text = myBtn[btnIndex].getText().toString();
                myBtn[btnIndex].setText("");
                myBtn[emptyIndex].setText(text);

                emptyIndex = btnIndex;

                counter += 1;
                tvCounter.setText("Moves : " + counter);

                if (gameIsOver()) {
                    Toast.makeText(this, "Game Is Over", Toast.LENGTH_LONG).show();
                    finish();
                }
            }
        }
    }

    private void newGame() {
        counter = 0;
        tvCounter.setText("Moves: " + counter);

        for (int i = 0; i < 16; i += 1) {
            myBtn[i].setText(i + 1 + "");
        }

        myBtn[15].setText("");
        emptyIndex = 15;

        shuffle(10);
    }

    private void saveGame() {
        Context context = getApplicationContext();
        SharedPreferences sp = context.getSharedPreferences("saved_game", Context.MODE_PRIVATE);

        // start editing
        SharedPreferences.Editor editor = sp.edit();

        // edit values to be saved
        editor.putInt("MovesCounter", counter);
        for (int i = 0; i < 16; i += 1) {
            editor.putString("Key" + i, myBtn[i].getText().toString());
        }

        // save all changes
        editor.commit();
        Toast.makeText(context, "Game has been saved!", Toast.LENGTH_LONG).show();
    }

    public boolean loadGame() {
        Context context = getApplicationContext();
        SharedPreferences sp = context.getSharedPreferences("saved_game", Context.MODE_PRIVATE);

        // get saved counter
        counter = sp.getInt("MovesCounter", -1);
        if (counter == -1) {
            return false;
        }

        tvCounter.setText(counter + "");
        for (int i = 0; i < 16; i++) {
            String savedText = sp.getString("Key" + i, "");
            myBtn[i].setText(savedText);

            if (savedText.equals("")) {
                emptyIndex = i;
            }
        }
        return true;
    }

    private boolean canMove(int btnIndex, int emptyIndex) {
        if (btnIndex == emptyIndex + 1 && btnIndex / 4 == emptyIndex / 4) {
            // move number to the left
            return true;
        } else if (btnIndex == emptyIndex - 1 && btnIndex / 4 == emptyIndex / 4) {
            // move number to the right
            return true;
        } else if (btnIndex == emptyIndex + 4) {
            // move number up
            return true;
        } else if (btnIndex == emptyIndex - 4) {
            // move number down
            return true;
        }

        return false;
    }

    private int getButtonIndex(int id) {
        for (int i = 0; i < 16; i++) {
            if (myBtn[i].getId() == id) {
                return i;
            }
        }

        return -1;
    }
}