如何在imageview中拖动时查找图像的结尾

Question

我有一个imageview并使用位图我正在显示图像。捏缩放由矩阵完成。对于缩放我使用“ Matrix.postScale ”方法。在平移（拖动）图像时，我需要限制拖动。当它到达图像的末尾时，我需要停止拖动。

在缩放图像时，图像视图的高度和宽度以及位图保持不变。如何在拖动时到达图像末尾时找到。

我在下面给出的代码和xml。

<AbsoluteLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/framlayout"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#000000"
android:orientation="vertical" >

 <ImageView 
    android:id="@+id/imageView1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_weight="0.70"
    android:layout_gravity="center"
    android:background="#000000"
    android:scaleType="matrix"
    />

Java代码在这里

  public boolean onTouch(View v, MotionEvent event) {

        ImageView view = (ImageView) v;
       switch (event.getAction() & MotionEvent.ACTION_MASK) {
        case MotionEvent.ACTION_DOWN:
            savedMatrix.set(matrix);
            start.set(event.getX(), event.getY());
            mode = DRAG;
            break;
        case MotionEvent.ACTION_POINTER_DOWN:
            oldDist = spacing(event);
            if (oldDist > 10f) {
                savedMatrix.set(matrix);
                midPoint(mid, event);
                mode = ZOOM;
            }
            break;
        case MotionEvent.ACTION_UP:
            if(!IsZoomMode){
            matrix.set(savedMatrix);
            matrix.postTranslate(0,0);
            }
            break;
        case MotionEvent.ACTION_POINTER_UP:

             mode = NONE;
            break;
        case MotionEvent.ACTION_MOVE:
            if(nTimerCountM < 30 &&  !bEnabledTaggingM)
             {              
                 nTimerCountM = 0;
            if (mode == DRAG) {
                matrix.set(savedMatrix);
                matrix.postTranslate(event.getX() - start.x, event.getY()
                        - start.y);                   
            } else if (mode == ZOOM) {
                IsZoomMode = true;
                float newDist = spacing(event);
                if (newDist > 10f) {
                    matrix.set(savedMatrix);
                    float scale = newDist / oldDist;
                    matrix.postScale(scale, scale, mid.x, mid.y);
                }                 
            }
          }
            break;
        }
        view.setImageMatrix(matrix);         
  }               
        return true;        
    }  
    /** Determine the space between the first two fingers */
private float spacing(MotionEvent 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, MotionEvent event) {
    float x = event.getX(0) + event.getX(1);
    float y = event.getY(0) + event.getY(1);
    point.set(x / 2, y / 2);