android - 将 Recycler View 项目拖放到 Image View

Question

我想将回收站 View 项目图像拖放到我的 ImageView (位于主布局中)。我怎样才能做到这一点？

我正在使用下面的代码来处理 longItemClickRecyclerViewItem

images_recycler.addOnItemTouchListener(
            new RecyclerItemClickListener(getActivity(), images_recycler ,new RecyclerItemClickListener.OnItemClickListener() {
                @Override public void onItemClick(View view, int position) {

                }

                @Override
                public void onItemLongClick(View view, int position) {


                }
            })
    );




public class RecyclerItemClickListener implements RecyclerView.OnItemTouchListener
{
    public static interface OnItemClickListener
    {
        public void onItemClick(View view, int position);
        void onItemLongClick(View view, int position);
     }

    private OnItemClickListener mListener;
    private GestureDetector mGestureDetector;

    public RecyclerItemClickListener(Context context, final RecyclerView recyclerView, OnItemClickListener listener)
    {
        mListener = listener;

        mGestureDetector = new GestureDetector(context, new GestureDetector.SimpleOnGestureListener()
        {
            @Override
            public boolean onSingleTapUp(MotionEvent e)
            {
                return true;
            }

            @Override
            public void onLongPress(MotionEvent e)
            {
                View childView = recyclerView.findChildViewUnder(e.getX(), e.getY());

                if(childView != null && mListener != null)
                {
                    mListener.onItemLongClick(childView, recyclerView.getChildPosition(childView));
                }
            }
        });
    }

    @Override
    public boolean onInterceptTouchEvent(RecyclerView view, MotionEvent e)
    {
        View childView = view.findChildViewUnder(e.getX(), e.getY());

        if(childView != null && mListener != null && mGestureDetector.onTouchEvent(e))
        {
            mListener.onItemClick(childView, view.getChildPosition(childView));
        }

        return false;
    }

    @Override
    public void onTouchEvent(RecyclerView view, MotionEvent motionEvent){}

    @Override
    public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept) {

    }
}

请帮我举一些例子或代码谢谢。

Answer 1

在这里查看我的答案 Drag View and Drop it on RecyclerView item Android .
但是你必须在这里做一些改变。在 onCreateViewHolder 方法中将 longClickListener 设置到回收站 View iteView 并对其进行充气。在那里你开始拖动。将 onDragListener 设置为您的 ImageView 您想要放置它的位置。

编辑

好的，我在这里添加一些代码。在回收器适配器的 onCreateViewHolder 中添加以下行:

@Override
public MemberHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    View view = LayoutInflater.from(context).inflate(R.layout.yourlayout, parent, false);
    view.setOnLongClickListener(new OnLongClickListener() {
        @Override
        public boolean onLongClick(View v) {
            ClipData.Item item = new ClipData.Item((CharSequence) view.getTag());
            String[] mimeTypes = {ClipDescription.MIMETYPE_TEXT_PLAIN};
            ClipData dragData = new ClipData(view.getTag().toString(),
                    mimeTypes, item);
            view.setVisibility(View.GONE);
            HeptagonDragShadowBuilder myShadow = new HeptagonDragShadowBuilder(Heptagon.this, 1.1f);

            if (VERSION.SDK_INT >= VERSION_CODES.N) {
                view.startDragAndDrop(dragData, myShadow, null, 0);
            } else {
                view.startDrag(dragData, myShadow, null, 0);
            }
            return true;
        }
    });

    return memberHolder;
}

在您要放置项目的 ImageView 中添加以下行:

imageView.setOnDragListener(new OnDragListener() {
    @Override
    public boolean onDrag(View view, DragEvent dragEvent) {

        switch (dragEvent.getAction()) {
            case DragEvent.ACTION_DRAG_STARTED:
                // drag has started, return true to tell that you're listening to the drag
                return true;

            case DragEvent.ACTION_DROP:
                // the dragged item was dropped into this view
                Category a = items.get(getAdapterPosition());
                a.setText("dropped");
                notifyItemChanged(getAdapterPosition());
                return true;
            case DragEvent.ACTION_DRAG_ENDED:
                // the drag has ended
                return false;
        }
        return false;
    }
});

编辑 2
好的，这是一个解释。当您将监听器分配给 View 时，您就是在告诉您要监听拖动事件。当拖动事件开始时，监听器的 onDrag 将被触发并执行 DragEvent.ACTION_DRAG_STARTED 操作。在这种情况下，在要放置项目的 View 监听器上返回 true 以告知此 View 想要捕获拖动的项目。当一个 View 被拖放到您正在收听的 View 上时，onDrag 会再次触发 DragEvent.ACTION_DROP 操作。在那里，您必须实现放下项目时要执行的逻辑。如果您想更改 imageview 的图像源或替换 imageview，您必须在 DragEvent.ACTION_DROP 案例中实现替换逻辑。拖动事件和监听器只会告诉您您正在拖动以及您正在放下的位置。所以任何其他逻辑都必须由你来完成。就我而言，我通知我的 recyclerview 适配器某些项目已更改。