Android 碎屏成效 (Crack Screen,击碎屏幕)

本文介绍一个好玩的App   如图：

实现思路：在一个透明的Activity上用一个自定义View，然后在View上画.9的碎玻璃图片，加上音效。然后过一段时间消失。

主要用一个postInvalidate();方法，用一个集合去装手指触摸过的地方，在touch事件中调用postInvalidate();方法进行视图重新绘制。

需要注意的是，这里的播放音效和上篇博客 Android 闪电效果 (Electric Screen,电动屏幕) 中的播放音效一样，暂停音效的时候要传开始播放时得到的int返回值，和停止音效不一样。

可以通过限制集合长度来限制绘制的屏幕个数。

单独开启一个线程，过一段时间开始清除效果， 即直接操作集合，操作完了调用postInvalidate(); 重新绘图就可以了。

示例代码：

public class CustomView extends View {	private Paint mPaint;	private SoundPool mSoundPool;	private Map<Integer, Integer> mSoundMap = new HashMap<Integer, Integer>();	private int mIndex;	private Bitmap mBitmap;	private ArrayList<Float> mXPointList;	private ArrayList<Float> mYPointList;	private int mCount = 0;// 点击次数	private int mLength = 30;// 绘制总数	public CustomView(Context context, AttributeSet attrs) {		super(context);		mPaint = new Paint();		mPaint.setAntiAlias(true);		mPaint.setColor(Color.BLUE);		// mPaint.setAlpha(127);		mPaint.setStrokeWidth(2.0f);		this.setKeepScreenOn(true);		this.setFocusable(true);		this.setLongClickable(true);		this.mSoundPool = new SoundPool(5, AudioManager.STREAM_SYSTEM, 5);		this.mSoundMap.put(1, mSoundPool.load(context, R.raw.cfokwowbfv, 1));		this.mBitmap = BitmapFactory.decodeResource(getResources(),				R.drawable.screen);		mXPointList = new ArrayList<Float>();		mYPointList = new ArrayList<Float>();		new Thread(new Runnable() {			@Override			public void run() {				// TODO Auto-generated method stub				while (true) {					try {						Thread.sleep(4000);					} catch (InterruptedException e) {						// TODO Auto-generated catch block						e.printStackTrace();					}					// mG++;					handler.sendEmptyMessage(0);				}			}		}).start();	}	@Override	public boolean onTouchEvent(MotionEvent arg1) {		// TODO Auto-generated method stub		switch (arg1.getAction()) {		case MotionEvent.ACTION_DOWN:			// drawBitmap(arg1.getX(), arg1.getY());			playSound();			mXPointList.add(arg1.getX());			mYPointList.add(arg1.getY());			postInvalidate();			mCount++;			if (mCount > mLength) {				mXPointList.remove(0);				mYPointList.remove(0);				mLength++;			}			break;		case MotionEvent.ACTION_UP:			break;		case MotionEvent.ACTION_MOVE:			break;		default:			break;		}		return super.onTouchEvent(arg1);	}	@Override	protected void onDraw(Canvas canvas) {		super.onDraw(canvas);		for (int i = 0; i < mXPointList.size(); ++i) {			canvas.drawBitmap(mBitmap, mXPointList.get(i) - mBitmap.getWidth()					/ 2, mYPointList.get(i) - mBitmap.getHeight() / 2, null);		}	}	// 播放	public void playSound() {		mIndex = mSoundPool.play(mSoundMap.get(1), 1, 1, 0, 0, 1);	}	// 停止播放	public void stopSound() {		// Toast.makeText(getContext(), "zzzzz", 0).show();		mSoundPool.stop(mIndex);	}	@Override	public boolean onKeyDown(int keyCode, KeyEvent event) {		// TODO Auto-generated method stub		Toast.makeText(getContext(), "keydown", Toast.LENGTH_SHORT).show();		return super.onKeyDown(keyCode, event);	}	// 更新界面	Handler handler = new Handler() {		public void handleMessage(Message msg) {			if (msg.what == 0) {				if (mCount != 0 && mXPointList.size() != 0) {					for (int i = 0; i < new Random()							.nextInt(mXPointList.size() + 1); i++) {						mXPointList.remove(0);						mYPointList.remove(0);						mLength++;					}				}				postInvalidate();			}		}	};}

Weibo: http://weibo.com/2382477985