Android Kanvas kilitleme özelliği IllegalArgumentException

Question

Dokunduğunda, kullanıcının ekrana dokunduğu noktada çember çizen kendi özel SurfaceView'ımı uygulamaya çalışıyorum. Ancak, mSurfaceHolder.lockCanvas()'u aradığımda bir istisna alıyorum. Kanvas kilitlendiğinde yasadışı bir argümanın çizgileri boyunca bir şey. Örnek kod aşağıda yer almaktadır.

01-17 00:19:44.703: E/Surface(9731): Surface::lock failed, already locked 
01-17 00:19:44.796: E/SurfaceHolder(9731): Exception locking surface 
01-17 00:19:44.796: E/SurfaceHolder(9731): java.lang.IllegalArgumentException 
01-17 00:19:44.796: E/SurfaceHolder(9731): at android.view.Surface.lockCanvasNative(Native Method) 
01-17 00:19:44.796: E/SurfaceHolder(9731): at android.view.Surface.lockCanvas(Surface.java:314) 
01-17 00:19:44.796: E/SurfaceHolder(9731): at android.view.SurfaceView$3.internalLockCanvas(SurfaceView.java:762) 
01-17 00:19:44.796: E/SurfaceHolder(9731): at android.view.SurfaceView$3.lockCanvas(SurfaceView.java:741) 
01-17 00:19:44.796: E/SurfaceHolder(9731): at com.frequency.FreqTapArea$2.onTouch(FreqTapArea.java:54) 
01-17 00:19:44.796: E/SurfaceHolder(9731): at android.view.View.dispatchTouchEvent(View.java:3897) 
01-17 00:19:44.796: E/SurfaceHolder(9731): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:869) 
01-17 00:19:44.796: E/SurfaceHolder(9731): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:869) 
01-17 00:19:44.796: E/SurfaceHolder(9731): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:869) 
01-17 00:19:44.796: E/SurfaceHolder(9731): at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:1737) 
01-17 00:19:44.796: E/SurfaceHolder(9731): at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1153) 
01-17 00:19:44.796: E/SurfaceHolder(9731): at android.app.Activity.dispatchTouchEvent(Activity.java:2096) 
01-17 00:19:44.796: E/SurfaceHolder(9731): at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1721) 
01-17 00:19:44.796: E/SurfaceHolder(9731): at android.view.ViewRoot.deliverPointerEvent(ViewRoot.java:2200) 
01-17 00:19:44.796: E/SurfaceHolder(9731): at android.view.ViewRoot.handleMessage(ViewRoot.java:1884) 
01-17 00:19:44.796: E/SurfaceHolder(9731): at android.os.Handler.dispatchMessage(Handler.java:99) 
01-17 00:19:44.796: E/SurfaceHolder(9731): at android.os.Looper.loop(Looper.java:130) 
01-17 00:19:44.796: E/SurfaceHolder(9731): at android.app.ActivityThread.main(ActivityThread.java:3835) 
01-17 00:19:44.796: E/SurfaceHolder(9731): at java.lang.reflect.Method.invokeNative(Native Method) 
01-17 00:19:44.796: E/SurfaceHolder(9731): at java.lang.reflect.Method.invoke(Method.java:507) 
01-17 00:19:44.796: E/SurfaceHolder(9731): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:847) 
01-17 00:19:44.796: E/SurfaceHolder(9731): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:605) 
01-17 00:19:44.796: E/SurfaceHolder(9731): at dalvik.system.NativeStart.main(Native Method) 

Yardım büyük takdir:

public class TapArea extends SurfaceView implements SurfaceHolder.Callback { 
    private static final int TAP_RADIUS = 4; 
    private boolean mLoaded = false; 
    private Paint mTapPaint; 
    private SurfaceHolder mSurfaceHolder; 

    protected OnTouchListener mTouchEvent = new OnTouchListener() { 
     @Override 
     public boolean onTouch(View arg0, MotionEvent arg1) { 
      if (!mLoaded) 
       return false; 

      Canvas c = null; 
      c = mSurfaceHolder.lockCanvas(); 
      drawTap(c, arg1); 

      return true; 
     } 
    }; 

    public TapArea(Context context, AttributeSet attrs) { 
     super(context, attrs); 

     this.setOnTouchListener(mTouchEvent); 
     mHandler = new Handler(); 
     mSurfaceHolder = getHolder(); 
     mSurfaceHolder.addCallback(this); 
     mTapPaint = new Paint(); 
    } 

    public void drawTap(Canvas canvas, MotionEvent tap) { 
     canvas.drawCircle(tap.getX(), tap.getY(), TAP_RADIUS, mTapPaint); 
    } 

    @Override 
    public void surfaceChanged(SurfaceHolder arg0, int arg1, int arg2, int arg3) { 
     // TODO Auto-generated method stub 

    } 

    @Override 
    public void surfaceCreated(SurfaceHolder arg0) { 
     // TODO Auto-generated method stub 
     mLoaded = true; 
    } 

    @Override 
    public void surfaceDestroyed(SurfaceHolder arg0) { 
     // TODO Auto-generated method stub 

    } 
} 

Aşağıda ben almaya devam hata kayıtları.

Answer 1

Üzerine çizdikten sonra tuvalin kilidini açmanız gerekir. doğru secuence geçerli:

1. olsun de tuval) (mSurfaceHolder.lockCanvas çağırarak;
2. Tuval üzerine çizim yapın.
3. Tuval aramayı açma mSurfaceHolder.unlockCanvasAndPost (c); Kodunuzda

olabilir:

public boolean onTouch(View arg0, MotionEvent arg1) { 
     if (!mLoaded) 
      return false; 

     Canvas c = mSurfaceHolder.lockCanvas(); 
     drawTap(c, arg1); 
     mSurfaceHolder.unlockCanvasAndPost(c); 

     return true; 
    }