android 雙緩沖技術

為了有效控制閃屏現象，可以使用雙緩沖來加載資源顯示。
/**
 * 雙緩沖技術實例
 * @author b
 *
 */
public class Surfaceview extends View implements Runnable{

	//要繪制的圖片
	private Bitmap mBitmap;
	private Paint paint;
	//內存一塊緩沖區
	private Bitmap sBitmap;
	private Canvas canvas;
	public Surfaceview(Context context) {
		super(context);
		//加載圖片到內存
		mBitmap = ((BitmapDrawable)getResources().getDrawable(R.drawable.b122)).getBitmap();
		//創建指定大小的緩沖區域
		sBitmap = Bitmap.createBitmap(1000, 800, Bitmap.Config.ARGB_8888);
		canvas = new Canvas();
		//
		canvas.setBitmap(sBitmap);
		paint = new Paint();
		//把圖片繪制在緩沖區域上
		canvas.drawBitmap(mBitmap, 0, 0, paint);
		new Thread(this).start();
	}

	@Override
	protected void onDraw(Canvas canvas) {
		super.onDraw(canvas);
		//將緩沖區域的圖片顯示出來
		canvas.drawBitmap(sBitmap, 0, 0, paint);
	}
	@Override
	public void run() {
		while(!Thread.currentThread().isInterrupted()){
			try {
				Thread.sleep(100);
			} catch (Exception e) {
				Thread.interrupted();
			}
			postInvalidate();
		}
	}

}