移动 imageview - 编程和 xml 实现中的不同行为

Question

我的目的是在地面上自由移动图像视图，因此我遵循了本教程： http://www.zdnet.com/blog/burnette/how-to-use-multi-touch-in-android-2-part-5-implementing-the-drag-gesture/1789

如果我按照那里声明的相同方式使用它 - 通过 id 获取视图组件并添加我的触摸监听器 - 它效果很好。另一方面，当我以编程方式创建视图时，它不会移动。

在我的活动中：

addProductToView(iterator.next());

在我的视图类中：

public class ProductView extends ImageView{
public ProductView(Context context, Product product) {
        super(context);
        this.setBackgroundResource(R.drawable.bamboo);
        this.setScaleType(ScaleType.MATRIX);
                this.setOnTouchListener(new TouchListener());
...

触摸监听器：

public class TouchListener implements OnTouchListener{

    private static final String TAG = "Touch";
       // These matrices will be used to move and zoom image
       Matrix matrix = new Matrix();
       Matrix savedMatrix = new Matrix();

       // We can be in one of these 3 states
       static final int NONE = 0;
       static final int DRAG = 1;
       static final int ZOOM = 2;
       int mode = NONE;

       // Remember some things for zooming
       PointF start = new PointF();
       PointF mid = new PointF();
       float oldDist = 1f;

//     @Override
//     public void onCreate(Bundle savedInstanceState) {
//        super.onCreate(savedInstanceState);
//        setContentView(R.layout.main);
//        ImageView view = (ImageView) findViewById(R.id.imageView);
//        view.setOnTouchListener(this);
//     }

       @Override
       public boolean onTouch(View v, MotionEvent 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(MotionEvent 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(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);
       }
}

我收到检测到拖动的日志信息，但我看不到任何变化。我的图像视图组件的声明出了什么问题？我需要将其声明为程序化的。

Answer 1

我猜你缺少 imageview 的可点击属性。当我们定义imageview时，我们要指定点击、移动、触摸的clickable属性。
您是否已在程序加载上实现了它？