Die GameOverActivity wird aktiv, wenn der Spieler keine Leben mehr übrig hat. Um das zu erreichen, müssen wir in unserer GameActivity folgende Methode einfügen:

public void onGameOver() {
    Intent theNextIntent = new Intent(getApplicationContext(), GameOverActivity.class);
    startActivity(theNextIntent);
    this.finish();
}

Um diese aufrufen zu können müssen wir global eine Instanz der GameActivity Klasse erstellen:

private GameActivity theGameActivity = new GameActivity();

Und dann noch einen Context der GameActivity in den Konstruktor der GameView Klasse:

theGameActivity = (GameActivity) context;

Daraufhin in der onTouchEvent() - Methoder der GameView Klasse folgendes einfügen:

if(lives==0){
    theGameActivity.onGameOver();
}

Dabei fragen wir ab, ob die übrigen Leben 0 sind, wenn das erfüllt ist, soll die Methode onGameOver() aufgerufen werden, die dafür sorgt, dass unsere GameActivity geschlossen wird und der Gameoverbildschirm geöffnet wird.

Dann sehen die drei Klassen wie folgt aus:

GameView

package com.panjutorials.lazypudding;

import java.util.ArrayList;
import java.util.List;
import java.util.Random;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Typeface;
import android.view.MotionEvent;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

public class GameView extends SurfaceView {
	private List<Sprite> spriteList = new ArrayList<Sprite>();
	private List<Integer> spriteListNum = new ArrayList<Integer>();
	private SurfaceHolder surfaceHolder;
	private Bitmap bmp;
	private Bitmap livesPicture;
	private GameLoopThread theGameLoopThread;
	private boolean createSprites = true;
	private long lastClick;
	private int currentColorNum;
	private int lives = 4;
	private int score = 0;
	private Paint paintRed, paintBlue, paintGreen, paintYellow;
	private Paint currentColor;
	private String scoreString;
	private String livesString;
	private float density;
	private GameActivity theGameActivity= new GameActivity();

	public GameView(Context context) {
		super(context);
		livesPicture = BitmapFactory.decodeResource(getResources(), R.drawable.lives);
		Random rnd = new Random();
		theGameActivity = (GameActivity) context;
		setColors();
		currentColorNum = rnd.nextInt(4);
		theGameLoopThread = new GameLoopThread(this);
		surfaceHolder = getHolder();
		surfaceHolder.addCallback(new SurfaceHolder.Callback() {

			public void surfaceDestroyed(SurfaceHolder holder) {
				boolean retry = true;
				theGameLoopThread.setRunning(false);
				while (retry) {
					try {
						theGameLoopThread.join();
						retry = false;
					} catch (InterruptedException e) {

					}
				}

			}

			public void surfaceCreated(SurfaceHolder holder) {
				theGameLoopThread.setRunning(true);
				theGameLoopThread.start();
			}

			public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
				// TODO Auto-generated method stub

			}
		});
	}

	@Override
	protected void onDraw(Canvas canvas) {
		canvas.drawColor(Color.DKGRAY);
		if (createSprites == true) {
			initialSprites();
		}
		for (Sprite sprite : spriteList) {
			sprite.onDraw(canvas);
		}
		if (currentColorNum == 0) {
			drawLines(paintBlue, canvas);
		} else if (currentColorNum == 1) {
			drawLines(paintRed, canvas);
		} else if (currentColorNum == 2) {
			drawLines(paintGreen, canvas);
		} else if (currentColorNum == 3) {
			drawLines(paintYellow, canvas);
		}
		final int fontSize = (int) (25 * density);
		int yTextPos = (int) (25 * density);
		Typeface font = Typeface.create("Arial", Typeface.NORMAL);

		Paint paint = new Paint();
		paint.setColor(Color.WHITE);
		paint.setTypeface(font);
		paint.setTextSize(fontSize);
		paint.setAntiAlias(true);
		scoreString = String.valueOf(score);
		int x = (canvas.getWidth() * 5 / 7);
		final String text = "Score: " + scoreString;
		canvas.drawText(text, x, yTextPos, paint);
		drawLives(canvas, paint);
	}

	private void createSprite(int index) {
		Bitmap bmp = null;
		switch (index) {
			case 0:
				bmp = BitmapFactory.decodeResource(getResources(),
				R.drawable.alienspriteblue);
				break;
			case 1:
				bmp = BitmapFactory.decodeResource(getResources(),
				R.drawable.alienspritered);
				break;
			case 2:
				bmp = BitmapFactory.decodeResource(getResources(),
				R.drawable.alienspritegreen);
				break;
			case 3:
				bmp = BitmapFactory.decodeResource(getResources(),
				R.drawable.alienspriteyellow);
				break;
		}
		Sprite sprite = new Sprite(this, bmp);
		spriteList.add(sprite);
		spriteListNum.add(index);
	}

	private void initialSprites() {
		for (int i = 0; i < 4; i++) {
			for (int j = 0; j < 3; j++)
				createSprite(i);
		}
		createSprites = false;
	}

	private void rndCreateSprite() {
		Random rnd = new Random(System.currentTimeMillis());
		int i = rnd.nextInt(4);
		createSprite(i);
	}

	@Override
	public boolean onTouchEvent(MotionEvent event) {
		if (System.currentTimeMillis() - lastClick > 300) {
			lastClick = System.currentTimeMillis();
			synchronized (getHolder()) {
				for (int i = spriteList.size() - 1; i >= 0; i--) {
					Sprite sprite = spriteList.get(i);
					if (sprite.isTouched(event.getX(), event.getY())) {
						if (currentColorNum == spriteListNum.get(i)) {
							score++;
						}else{
							lives--;
							if(lives==0){
								theGameActivity.onGameOver();
							}
						}
						if(score==3)
							lives++;
						rndCreateSprite();
						removeSprite(i);
						changeColor();
						break;
					}
				}
			}
		}
		return true;
	}

	private void removeSprite(int index) {
		spriteList.remove(index);
		spriteListNum.remove(index);
	}

	public void setColors() {
		Paint paintRed = new Paint();
		paintRed.setARGB(255, 236, 27, 36);
		this.paintRed = paintRed;
		Paint paintBlue = new Paint();
		paintBlue.setARGB(255, 36, 72, 204);
		this.paintBlue = paintBlue;
		Paint paintGreen = new Paint();
		paintGreen.setARGB(255, 34, 177, 76);
		this.paintGreen = paintGreen;
		Paint paintYellow = new Paint();
		paintYellow.setARGB(255, 255, 242, 0);
		this.paintYellow = paintYellow;
	}

	public void drawLines(Paint lineColor, Canvas canvas) {
		int lineWidth = (int) (10*density);
		int screenHeight = getHeight();
		int screenWidth = getWidth();
		canvas.drawRect(0, 0, lineWidth, getHeight(), lineColor);
		canvas.drawRect(0, getHeight() - lineWidth, screenWidth, screenHeight, lineColor);
		canvas.drawRect(screenWidth - lineWidth, 0, screenWidth, screenHeight, lineColor);
		currentColor = lineColor;
	}

	public void changeColor() {
		Random rnd = new Random();
		int index = rnd.nextInt(spriteListNum.size());
		this.currentColorNum = spriteListNum.get(index);
		switch (index) {
			case 0:
				currentColor = paintBlue;
				break;
			case 1:
				currentColor = paintRed;
				break;
			case 2:
				currentColor = paintGreen;
				break;
			case 3:
				currentColor = paintYellow;
				break;
		}

	}

	public float getDensity() {
		density = getResources().getDisplayMetrics().density;
		return density;
	}

	private void drawLives(Canvas canvas, Paint paint){
		int xHeart= (int) (15*density);
		int yHeart= (int) (12*density);
		if (lives == 3) {
			canvas.drawBitmap(livesPicture, xHeart, yHeart, paint);
			canvas.drawBitmap(livesPicture, xHeart + livesPicture.getWidth() + 3*density, yHeart, paint);
			canvas.drawBitmap(livesPicture, xHeart + 2 * livesPicture.getWidth() + 6*density, yHeart, paint);
		}
		if (lives == 2) {
			canvas.drawBitmap(livesPicture, xHeart,
			yHeart, paint);
			canvas.drawBitmap(livesPicture, xHeart + livesPicture.getWidth() + 3, yHeart, paint);
		}
		if (lives == 1) {
			canvas.drawBitmap(livesPicture, xHeart, yHeart, paint);
		}
		if (lives > 3) {
			livesString = String.valueOf(lives);
			final String lives = livesString + "x";
			canvas.drawText(lives, 35 * getDensity(), 30 * getDensity(), paint);
			canvas.drawBitmap(livesPicture, 15 * getDensity() + 2 * livesPicture.getWidth() + 6, 12 * getDensity(), paint);
		}
	}
}

GameActivity

package com.panjutorials.lazypudding;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;

public class GameActivity extends Activity {
	/** Called when the activity is first created. */
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(new GameView(this));
	}

	public void onGameOver() {
		Intent theNextIntent = new Intent(getApplicationContext(), GameOverActivity.class);
		startActivity(theNextIntent);
		this.finish();
	}
}

GameOverActivity

package com.panjutorials.lazypudding;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class GameOverActivity extends Activity implements OnClickListener{

	private Button bReplay;
	private Button bExit;

	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.gameoverscreen);
		bReplay = (Button) findViewById(R.id.bReplay);
		bExit = (Button) findViewById(R.id.bExit);
		bReplay.setOnClickListener(this);
		bExit.setOnClickListener(this);
	}

	public void onClick(View v) {
		switch (v.getId()) {
			case R.id.bReplay:
				Intent newGameScreen= new Intent(getApplicationContext(), GameActivity.class);
				startActivity(newGameScreen);
				this.finish();
				break;
			case R.id.bExit:
				this.finish();
				break;
			}
		}

}