Surfaceview 闪烁 [英] Surfaceview flickering

问题描述

我有闪烁的问题.这是我的代码.

I have a problem with the flickering. Here is my code.

public class Tutorial2D3 extends Activity {

Panel panel;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    panel = new Panel(this);
    setContentView(panel);
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    menu.add(1, 1, 1, "Clean Canvas");
    return super.onCreateOptionsMenu(menu);
}

@Override
public boolean onMenuItemSelected(int featureId, MenuItem item) {
    panel.cleanCanvas();
    return true;
}

class Panel extends SurfaceView implements SurfaceHolder.Callback {
    TutorialThread thread;
    Bitmap icon;
    int iconWidth;
    int iconHeight;
    int touchX;
    int touchY;
    int mCount = 0;

    public Panel(Context context) {
        super(context);
        icon = BitmapFactory
                .decodeResource(getResources(), R.drawable.icon);
        iconWidth = icon.getWidth();
        iconHeight = icon.getHeight();
        getHolder().addCallback(this);
        thread = new TutorialThread(getHolder(), this);
        setFocusable(true);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        int x = touchX - (iconWidth / 2);
        int y = touchY - (iconHeight / 2);
        if(mCount>0) {
            canvas.drawColor(Color.BLACK);
            mCount--;
        }
        canvas.drawBitmap(icon, (x > 0 ? x : 0), (y > 0 ? y : 0), null);    
    }

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

    }

    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        thread.setRunning(true);
        thread.start();
    }

    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        boolean retry = true;
        thread.setRunning(false);
        do {
            try {
                thread.join();
                retry = false;
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        } while (retry);
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        switch (event.getAction()) {
        case MotionEvent.ACTION_DOWN:
            touchX = (int) event.getX();
            touchY = (int) event.getY();
            break;
        case MotionEvent.ACTION_MOVE:
            touchX = (int) event.getX();
            touchY = (int) event.getY();
            break;
        case MotionEvent.ACTION_UP:
            break;
        default:
            break;
        }
        return true;
    }

    private void cleanCanvas() {
        mCount = 2;
    }
}



class TutorialThread extends Thread {
    private SurfaceHolder _surfaceHolder;
    private Panel _panel;
    private boolean _run = false;

    public TutorialThread(SurfaceHolder surfaceHolder, Panel panel) {
        _surfaceHolder = surfaceHolder;
        _panel = panel;
    }

    public void setRunning(boolean run) {
        _run = run;
    }

    @Override
    public void run() {
        Canvas c;
        while (_run) {
            c = null;
            try {
                c = _surfaceHolder.lockCanvas(null);
                synchronized (_surfaceHolder) {
                    _panel.onDraw(c);
                }
            } finally {
                if (c != null) {
                    _surfaceHolder.unlockCanvasAndPost(c);
                }
            }
        }
    }
}

}

绘制的图像闪烁.看起来在一个点绘制的位图是在一个表面而不是另一个表面上绘制的，所以看起来像闪烁，当我们触摸action_up时绘制的位图完成，这是一个实体图像，不闪烁.有人可以帮我解决这个问题吗?谢谢

The drawn image flickers. It looks like the bitmap that is drawn at one point is drawn on one surface and not the other so it looks like flickering, the bitmap that is drawn when we touch action_up is done, that is a solid image and does not flickers. Could someone please help me with this one. Thanks

推荐答案

我没有通读所有的代码，但我认为 这篇文章会有所帮助.

I didn't read through all of your code, but I think this article will help.

文章的本质是闪烁是由于双缓冲造成的，可以通过不绘制到参数 Canvas 而是绘制用作画布的位图，然后将该位图绘制到 arg Canvas 来消除闪烁:

The essence of the article is that flickering is due to double buffering and can be eliminated by drawing not to the argument Canvas but to a bitmap used as the canvas and then drawing that bitmap to the arg Canvas:

int myCanvas_w, myCanvas_h;
Bitmap myCanvasBitmap = null;
Canvas myCanvas = null;
Matrix identityMatrix;

@Override
public void surfaceCreated(SurfaceHolder holder) {

myCanvas_w = getWidth();
myCanvas_h = getHeight();
myCanvasBitmap = Bitmap.createBitmap(myCanvas_w, myCanvas_h, Bitmap.Config.ARGB_8888);
myCanvas = new Canvas();
myCanvas.setBitmap(myCanvasBitmap);

identityMatrix = new Matrix();
}

@Override
protected void onDraw(Canvas canvas) {

paint.setStyle(Paint.Style.STROKE);
 paint.setStrokeWidth(3);

 //int w = myCanvas.getWidth();
 //int h = myCanvas.getHeight();
 int x = random.nextInt(myCanvas_w-1);
 int y = random.nextInt(myCanvas_h-1);
 int r = random.nextInt(255);
 int g = random.nextInt(255);
 int b = random.nextInt(255);

 paint.setColor(0xff000000 + (r << 16) + (g << 8) + b);
 myCanvas.drawPoint(x, y, paint); // <--------- Here's where you draw on your bitmap

 canvas.drawBitmap(myCanvasBitmap, identityMatrix, null);
 // ^---------- And here's where you draw that bitmap to the canvas

}

这篇关于Surfaceview 闪烁的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！