Mục tiêu của tài liệu hướng dẫn bạn làm quen với một vài kỹ thuật đơn giản trong lập trình Game 2D Android. Bao gồm: sử dụng SuffaceView, vẽ trên Canvas, chuyển động của các , nhân vật game, tương tác với cử chỉ của người chơi.

Xem phần 1 tại đây

Xem phần 2 tại đây

Xem phần 3 tại đây

9- Hiệu ứng âm thanh trong trò chơi (Version: Release)

Tiếp theo bạn cần thêm hiệu ứng âm thanh vào trò chơi, chẳng hạn âm thanh nền của trò chơi, âm thanh tiếng nổ khi nhân vật Chibi bị phá hủy.

Explosion.java

package org.o7planning.android2dgame;
 
import android.graphics.Bitmap;
import android.graphics.Canvas;
 
public class Explosion extends GameObject {
 
    private int rowIndex = 0 ;
    private int colIndex = -1 ;
 
    private boolean finish= false;
    private GameSurface gameSurface;
 
    public Explosion(GameSurface GameSurface, Bitmap image, int x, int y) {
        super(image, 5, 5, x, y);
 
        this.gameSurface= GameSurface;
    }
 
    public void update()  {
        this.colIndex++;
 
        // Play sound explosion.wav.
        if(this.colIndex==0 && this.rowIndex==0) {
            this.gameSurface.playSoundExplosion();
        }
 
        if(this.colIndex >= this.colCount)  {
            this.colIndex =0;
            this.rowIndex++;
 
            if(this.rowIndex>= this.rowCount)  {
                this.finish= true;
            }
        }
    }
 
    public void draw(Canvas canvas)  {
        if(!finish)  {
            Bitmap bitmap= this.createSubImageAt(rowIndex,colIndex);
            canvas.drawBitmap(bitmap, this.x, this.y,null);
        }
    }
 
    public boolean isFinish() {
        return finish;
    }
 
}

GameSurface.java

package org.o7planning.android2dgame;
 
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.media.AudioAttributes;
import android.media.AudioManager;
import android.media.SoundPool;
import android.os.Build;
import android.view.MotionEvent;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
 
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
 
public class GameSurface extends SurfaceView implements SurfaceHolder.Callback {
 
    private GameThread gameThread;
 
    private final List<ChibiCharacter> chibiList = new ArrayList<ChibiCharacter>();
    private final List<Explosion> explosionList = new ArrayList<Explosion>();
 
    private static final int MAX_STREAMS=100;
    private int soundIdExplosion;
    private int soundIdBackground;
 
    private boolean soundPoolLoaded;
    private SoundPool soundPool;
 
 
 
    public GameSurface(Context context)  {
        super(context);
 
        // Make Game Surface focusable so it can handle events.
        this.setFocusable(true);
 
        // Sét callback.
        this.getHolder().addCallback(this);
 
        this.initSoundPool();
    }
 
    private void initSoundPool()  {
        // With Android API >= 21.
        if (Build.VERSION.SDK_INT >= 21 ) {
 
            AudioAttributes audioAttrib = new AudioAttributes.Builder()
                    .setUsage(AudioAttributes.USAGE_GAME)
                    .setContentType(AudioAttributes.CONTENT_TYPE_SONIFICATION)
                    .build();
 
            SoundPool.Builder builder= new SoundPool.Builder();
            builder.setAudioAttributes(audioAttrib).setMaxStreams(MAX_STREAMS);
 
            this.soundPool = builder.build();
        }
        // With Android API < 21
        else {
            // SoundPool(int maxStreams, int streamType, int srcQuality)
            this.soundPool = new SoundPool(MAX_STREAMS, AudioManager.STREAM_MUSIC, 0);
        }
 
        // When SoundPool load complete.
        this.soundPool.setOnLoadCompleteListener(new SoundPool.OnLoadCompleteListener() {
            @Override
            public void onLoadComplete(SoundPool soundPool, int sampleId, int status) {
                soundPoolLoaded = true;
 
                // Playing background sound.
                playSoundBackground();
            }
        });
 
        // Load the sound background.mp3 into SoundPool
        this.soundIdBackground= this.soundPool.load(this.getContext(), R.raw.background,1);
 
        // Load the sound explosion.wav into SoundPool
        this.soundIdExplosion = this.soundPool.load(this.getContext(), R.raw.explosion,1);
 
 
    }
 
    public void playSoundExplosion()  {
        if(this.soundPoolLoaded) {
            float leftVolumn = 0.8f;
            float rightVolumn =  0.8f;
            // Play sound explosion.wav
            int streamId = this.soundPool.play(this.soundIdExplosion,leftVolumn, rightVolumn, 1, 0, 1f);
        }
    }
 
    public void playSoundBackground()  {
        if(this.soundPoolLoaded) {
            float leftVolumn = 0.8f;
            float rightVolumn =  0.8f;
            // Play sound background.mp3
            int streamId = this.soundPool.play(this.soundIdBackground,leftVolumn, rightVolumn, 1, -1, 1f);
        }
    }
 
    @Override
    public boolean onTouchEvent(MotionEvent event) {
        if (event.getAction() == MotionEvent.ACTION_DOWN) {
 
            int x=  (int)event.getX();
            int y = (int)event.getY();
 
            Iterator<ChibiCharacter> iterator= this.chibiList.iterator();
 
 
            while(iterator.hasNext()) {
                ChibiCharacter chibi = iterator.next();
                if( chibi.getX() < x && x < chibi.getX() + chibi.getWidth()
                        && chibi.getY() < y && y < chibi.getY()+ chibi.getHeight())  {
                    // Remove the current element from the iterator and the list.
                    iterator.remove();
 
                    // Create Explosion object.
                    Bitmap bitmap = BitmapFactory.decodeResource(this.getResources(),R.drawable.explosion);
                    Explosion explosion = new Explosion(this, bitmap,chibi.getX(),chibi.getY());
 
                    this.explosionList.add(explosion);
                }
            }
 
 
            for(ChibiCharacter chibi: chibiList) {
                int movingVectorX =x-  chibi.getX() ;
                int movingVectorY =y-  chibi.getY() ;
                chibi.setMovingVector(movingVectorX, movingVectorY);
            }
            return true;
        }
        return false;
    }
 
    public void update()  {
        for(ChibiCharacter chibi: chibiList) {
            chibi.update();
        }
        for(Explosion explosion: this.explosionList)  {
            explosion.update();
        }
 
        Iterator<Explosion> iterator= this.explosionList.iterator();
        while(iterator.hasNext())  {
            Explosion explosion = iterator.next();
 
            if(explosion.isFinish()) {
                // If explosion finish, Remove the current element from the iterator & list.
                iterator.remove();
                continue;
            }
        }
    }
 
    @Override
    public void draw(Canvas canvas)  {
        super.draw(canvas);
 
        for(ChibiCharacter chibi: chibiList)  {
            chibi.draw(canvas);
        }
 
        for(Explosion explosion: this.explosionList)  {
            explosion.draw(canvas);
        }
 
    }
 
    // Implements method of SurfaceHolder.Callback
    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        Bitmap chibiBitmap1 = BitmapFactory.decodeResource(this.getResources(),R.drawable.chibi1);
        ChibiCharacter chibi1 = new ChibiCharacter(this,chibiBitmap1,100,50);
 
        Bitmap chibiBitmap2 = BitmapFactory.decodeResource(this.getResources(),R.drawable.chibi2);
        ChibiCharacter chibi2 = new ChibiCharacter(this,chibiBitmap2,300,150);
 
        this.chibiList.add(chibi1);
        this.chibiList.add(chibi2);
 
        this.gameThread = new GameThread(this,holder);
        this.gameThread.setRunning(true);
        this.gameThread.start();
    }
 
    // Implements method of SurfaceHolder.Callback
    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
 
    }
 
    // Implements method of SurfaceHolder.Callback
    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        boolean retry= true;
        while(retry) {
            try {
                this.gameThread.setRunning(false);
 
                // Parent thread must wait until the end of GameThread.
                this.gameThread.join();
            }catch(InterruptedException e)  {
                e.printStackTrace();
            }
            retry= true;
        }
    }
 
}

OK, bây giờ bạn có thể chạy lại trò chơi và nghe hiệu ứng âm thanh của trò chơi.