Android旋轉圖像ontouch

Question

我正在處理一段代碼，它縮放圖像，放大並使用onTouchListener移動。現在我想通過觸摸來旋轉圖像，下面是我的代碼：

@Override 
    public boolean onTouch(View v, MotionEvent rawEvent) { 
     WrapMotionEvent event = WrapMotionEvent.wrap(rawEvent); 
     // ... 
      int rotation = 25; 
      // Dump touch event to log 
      dumpEvent(event); 
     ImageView view = (ImageView) v; 

     // Dump touch event to log 
     dumpEvent(event); 

     // Handle touch events here... 
     switch (event.getAction() & MotionEvent.ACTION_MASK) { 
     case MotionEvent.ACTION_DOWN: 
      savedMatrix.set(matrix); 
      start.set(event.getX(), event.getY()); 
      Log.d(TAG, "mode=DRAG"); 
      mode = DRAG; 
      break; 
     case MotionEvent.ACTION_POINTER_DOWN: 
      oldDist = spacing(event); 
      Log.d(TAG, "oldDist=" + oldDist); 
      if (oldDist > 10f) { 
       savedMatrix.set(matrix); 
       midPoint(mid, event); 
       mode = ZOOM; 
       Log.d(TAG, "mode=ZOOM"); 
      } 
      break; 
     case MotionEvent.ACTION_UP: 
     case MotionEvent.ACTION_POINTER_UP: 
      mode = NONE; 
      Log.d(TAG, "mode=NONE"); 
      break; 
     case MotionEvent.ACTION_MOVE: 
      if (mode == DRAG) { 
       // ... 
       matrix.set(savedMatrix); 
       matrix.postTranslate(event.getX() - start.x, event.getY() 
         - start.y); 
      } else if (mode == ZOOM) { 
       float newDist = spacing(event); 
       Log.d(TAG, "newDist=" + newDist); 
       if (newDist > 10f) { 
        matrix.set(savedMatrix); 
        float scale = newDist/oldDist; 
        matrix.postScale(scale, scale, mid.x, mid.y); 
       } 
      } 
      break; 

     } 

     view.setImageMatrix(matrix); 
     return true; // indicate event was handled 
    } 

    /** Show an event in the LogCat view, for debugging */ 
    private void dumpEvent(WrapMotionEvent event) { 
     // ... 
     String names[] = { "DOWN", "UP", "MOVE", "CANCEL", "OUTSIDE", 
       "POINTER_DOWN", "POINTER_UP", "7?", "8?", "9?" }; 
     StringBuilder sb = new StringBuilder(); 
     int action = event.getAction(); 
     int actionCode = action & MotionEvent.ACTION_MASK; 
     sb.append("event ACTION_").append(names[actionCode]); 
     if (actionCode == MotionEvent.ACTION_POINTER_DOWN 
       || actionCode == MotionEvent.ACTION_POINTER_UP) { 
      sb.append("(pid ").append(
        action >> MotionEvent.ACTION_POINTER_ID_SHIFT); 
      sb.append(")"); 
     } 
     sb.append("["); 
     for (int i = 0; i < event.getPointerCount(); i++) { 
      sb.append("#").append(i); 
      sb.append("(pid ").append(event.getPointerId(i)); 
      sb.append(")=").append((int) event.getX(i)); 
      sb.append(",").append((int) event.getY(i)); 
      if (i + 1 < event.getPointerCount()) 
       sb.append(";"); 
     } 
     sb.append("]"); 
     Log.d(TAG, sb.toString()); 
    } 

    /** Determine the space between the first two fingers */ 
    private float spacing(WrapMotionEvent event) { 
     // ... 
     float x = event.getX(0) - event.getX(1); 
     float y = event.getY(0) - event.getY(1); 
     return FloatMath.sqrt(x * x + y * y); 
    } 

    /** Calculate the mid point of the first two fingers */ 
    private void midPoint(PointF point, WrapMotionEvent event) { 
     // ... 
     float x = event.getX(0) + event.getX(1); 
     float y = event.getY(0) + event.getY(1); 
     point.set(x/2, y/2); 
    } 

我想我差不多了，任何人都可以請幫我與上面​​提到的特徵一起解決問題，旋轉...謝謝提前..

Answer 1

你已經得到了matrix.postTranslate和matrix.postScale。所有你需要添加的是matrix.postRotate！ :)

http://developer.android.com/reference/android/graphics/Matrix.html

檢查了這一點：

http://mobile.tutsplus.com/tutorials/android/android-sdk-creating-a-rotating-dialer/