拖放方法在第一次使用时不正确

Question

我想用拖放的方法在用户拖放的屏幕上放置几个视图对象。但这在第一次使用时出现了奇怪的错误，它没有放在用户离开的地方，而是放在一个非常不相关的地方，有时甚至在屏幕之外。但是，第一次使用后，就没有这个问题了。它把它放在我想要的地方。这个问题的根源是什么？

setOnDragListener()

contentTableLayout.setOnDragListener(new View.OnDragListener() {
  @Override
  public boolean onDrag(View view, DragEvent event) {
    Log.i(TAG, " event.getAction(): " + event.getAction() + " getView: ID: " + view.getId() + " getContext: " + view.getContext());
    String getImageFileNameSelectedRoom = getImageFileNameToRoom();

    switch (event.getAction()) {

    case DragEvent.ACTION_DRAG_STARTED:
      if (event.getClipDescription().hasMimeType(ClipDescription.MIMETYPE_TEXT_PLAIN)) {
        View draggedView = (View) event.getLocalState();
        initialX = draggedView.getX();
        initialY = draggedView.getY();
        Log.i(TAG, "ACTION_DRAG_STARTED -> initialX: " + initialX + " initialY: " + initialY);
   
        changeBackgroundColorOnDrag(view, "#664CAF50", true);

        return true;

      }
      return event.getClipDescription().hasMimeType(ClipDescription.MIMETYPE_TEXT_PLAIN);

    case DragEvent.ACTION_DRAG_ENTERED:
      changeBackgroundColorOnDrag(view, "#664CAF50", true);

      return true;

    case DragEvent.ACTION_DRAG_LOCATION:
      return true;

    case DragEvent.ACTION_DRAG_EXITED:

      changeBackgroundColorOnDrag(view, "#66D32121", true);
      return true;

    case DragEvent.ACTION_DROP:
      Log.i(TAG, "ACTION_DROP -> ");


      View draggedView = (View) event.getLocalState();
      ViewGroup owner = (ViewGroup) draggedView.getParent();
      owner.removeView(draggedView);

      FrameLayout container = (FrameLayout) view;
      container.addView(draggedView);

      View.DragShadowBuilder shadowBuilder = new View.DragShadowBuilder(draggedView);
      Point shadowSize = new Point();
      shadowBuilder.onProvideShadowMetrics(shadowSize, new Point());

      int x = (int) event.getX() - draggedView.getMeasuredWidth() / 2;
      int y = (int) event.getY() - draggedView.getMeasuredHeight() / 2;


      draggedView.setLayoutParams(new FrameLayout.LayoutParams(
        FrameLayout.LayoutParams.WRAP_CONTENT,
        FrameLayout.LayoutParams.WRAP_CONTENT));

      Log.i(TAG, "ACTION_DROP -> " + x + "  y: " + y);

      draggedView.setX(x);
      draggedView.setY(y);

      draggedView.setVisibility(View.VISIBLE);
      return true;

    case DragEvent.ACTION_DRAG_ENDED:
      if (!event.getResult()) {

        if (getImageFileNameSelectedRoom != null) {
          File targetFile = findImageFile(getImageFileNameSelectedRoom);

          if (targetFile != null) {
            Bitmap bitmap = BitmapFactory.decodeFile(targetFile.getAbsolutePath());
            BitmapDrawable bitmapDrawable = new BitmapDrawable(getResources(), bitmap);
            ((FrameLayout) view).setBackground(bitmapDrawable);

            view.invalidate();
          } else {
            Log.e(TAG, "Resim dosyası bulunamadı.");
          }

        }

        View droppedView = (View) event.getLocalState();
        droppedView.setVisibility(View.VISIBLE);
      }
      return true;

    default:
      break;
    }
    return false;
  }
});

setOnLongListener()

mainView.setOnLongClickListener(new View.OnLongClickListener() {
                @Override
                public boolean onLongClick(View view) {
                    ClipData.Item item = new ClipData.Item((CharSequence) view.getTag());
                    ClipData dragData = new ClipData((CharSequence) view.getTag(), new String[]{ClipDescription.MIMETYPE_TEXT_PLAIN}, item);
                    View.DragShadowBuilder shadowBuilder = new View.DragShadowBuilder(view);
                    Log.i(TAG, " getXFromView: " + view.getX() + "getYFromView: " + view.getY());


                    view.startDrag(dragData, shadowBuilder, view, 0);
                    return true;
                }
            });

在上面的代码中，第一个拖放操作不正确。当我尝试下面的代码时，第一次拖放操作没问题，但这次接下来的就坏了。

case DragEvent.ACTION_DROP:
    // ...
    int x = (int) (initialX + event.getX() - shadowSize.x / 2);
    int y = (int) (initialY + event.getY() - shadowSize.y / 2);

//initialX and initialY values come from the ACTION_DRAG_STARTED case.
    // ...

Answer 1

确保窗口（驱动程序）最大化

Answer 2

在其他来源的帮助下解决了问题。

当我删除下面的代码时，所有拖放功能都可以正常工作：

draggedView.setLayoutParams(new FrameLayout.LayoutParams(
        FrameLayout.LayoutParams.WRAP_CONTENT,
        FrameLayout.LayoutParams.WRAP_CONTENT));