如何知道用户何时完成移动 RecyclerView 项目？

Question

我需要在用户放下物品时执行某些操作。 ItemTouchHelper 似乎只有对 onMove 和 onMoved 的调用，无论用户是否真的完成了项目的移动，它们都会发生。我如何知道用户何时完成移动项目？也就是说，他们松开了手指并将物品放回了 recyclerView？

Answer 1

您可以覆盖 onSelectedChanged() ItemTouchHelper.Callback class 实现的回调，并使用可以是 (ACTION_STATE_DRAG, ACTION_STATE_SWIPE, & ACTION_STATE_IDLE).

ACTION_STATE_IDLE 是您要查找的内容，它将在 swipe/drag 操作结束并且用户将手指离开屏幕时触发

您可以使用布尔值来判断它是滑动还是拖动，如下所示。

private ItemTouchHelper createHelperCallback() {
    return new ItemTouchHelper(new ItemTouchHelper.Callback() {

        final boolean[] isSwiped = {false};

        @Override
        public int getMovementFlags(@NonNull RecyclerView recyclerView, @NonNull RecyclerView.ViewHolder viewHolder) {
            return 0;
        }

        @Override
        public boolean onMove(@NonNull RecyclerView recyclerView, @NonNull RecyclerView.ViewHolder viewHolder, @NonNull RecyclerView.ViewHolder target) {
            return true;
        }

        @Override
        public void onSwiped(@NonNull RecyclerView.ViewHolder viewHolder, int direction) {
        }

        @Override
        public void onSelectedChanged(@Nullable RecyclerView.ViewHolder viewHolder, int actionState) {

            switch (actionState) {

                case ItemTouchHelper.ACTION_STATE_DRAG:
                    // the user is dragging an item and didn't lift their finger off yet
                   isSwiped[0] = false;
                   break;

                case ItemTouchHelper.ACTION_STATE_SWIPE:
                    // the user is swiping an item and didn't lift their finger off yet
                    isSwiped[0] = true;
                    break;

                case ItemTouchHelper.ACTION_STATE_IDLE:
                    // the user just dropped the item (after dragging it), and lift their finger off.

                    if (isSwiped[0]) // The user used onSwiped()
                        Toast.makeText(MainActivity.this, "Swiping is over", Toast.LENGTH_SHORT).show();
                        
                    else // The user used onMove()
                        Toast.makeText(MainActivity.this, "Dragging & Dropping are over", Toast.LENGTH_SHORT).show();
                
            }
        }

    });
}

然后在你的 RecyclerView 上使用它

createHelperCallback().attachToRecyclerView(recyclerView);

预览

Answer 2

简单。只需覆盖 onClearView():

@Override
public void clearView(@NonNull RecyclerView recyclerView, @NonNull RecyclerView.ViewHolder viewHolder) {    //called when you dropped the item
    super.clearView(recyclerView, viewHolder);

    Toast.makeText(recyclerView.getContext(), "Item dropped on position: " + viewHolder.getAdapterPosition(), Toast.LENGTH_SHORT).show();
}

Answer 3

你也可以覆盖getAnimationDuration()，它在onSelectedChanged()之前调用（当用户的手指向上时）但是你不能在这个函数中访问viewHolder。

如何知道用户何时完成移动 RecyclerView 项目？

How to know when user is done moving a RecyclerView item?

android

android-recyclerview

itemtouchhelper