Make a scrollView autoscroll with drag and drop in Android

Question

I searched all over, but could not find a solution.

I have a view (lets call it myView) inside a scrollview. myView is bigger than the screen. Since I\'m able to get

Answer 1

I came up with a different solution and I am happy with it.

I want to be able to drag and drop views inside a ScrollView. The ScrollView then needs to scroll up and down automatically when the shadow reaches the edges of the scroll view.

I ended up with a solution that detects wether the drop zone is completely visible inside the scrollview (with a 100px margin) and adjust the scroll view otherwise.

@Override
public boolean onDrag(View view, DragEvent event) {

    MainWidget dropZoneView = (MainWidget) view;

    int action = event.getAction();
    switch (action) {
        case DragEvent.ACTION_DRAG_STARTED:
        //(... other stuff happens here)
        case DragEvent.ACTION_DRAG_LOCATION:

            ScrollView mainScrollView = (ScrollView) findViewById(R.id.main_scroll);

            int topOfDropZone = dropZoneView.getTop();
            int bottomOfDropZone = dropZoneView.getBottom();

            int scrollY = mainScrollView.getScrollY();
            int scrollViewHeight = mainScrollView.getMeasuredHeight();

            Log.d(LOG_TAG,"location: Scroll Y: "+ scrollY + " Scroll Y+Height: "+(scrollY + scrollViewHeight));
            Log.d(LOG_TAG," top: "+ topOfDropZone +" bottom: "+bottomOfDropZone);

            if (bottomOfDropZone > (scrollY + scrollViewHeight - 100))
                mainScrollView.smoothScrollBy(0, 30);

            if (topOfDropZone < (scrollY + 100))
                mainScrollView.smoothScrollBy(0, -30);

            break;
        default:
            break;
    }
    return true;
}

Hope this helps!