问Android RecyclerView 拖拽闪烁问题？

提问于 2024-05-23 21:04:10

回答 0关注 1查看 44

我用RecyclerVIew实现一个宫格样式，中间一项itemtype不同作为标题分割，添加了拖拽ItemTouchHelper，但是当我拖拽越过中间的标题时，标题前后的item移动动画变成淡入淡出，并且标题会闪烁一下。请问是为什么？

public class MyItemTouchHelper extends ItemTouchHelper.Callback{
        private List<MenuInfo> pictureBeans;
        private ModuleAdapter recycleViewAdapter;
        Activity activity;
        public MyItemTouchHelper(Activity activity, List<MenuInfo> pictureBeans, ModuleAdapter recycleViewAdapter) {
            Log.d("dddd","into MyItemTouchHelper");
            this.pictureBeans = pictureBeans;
            this.recycleViewAdapter = recycleViewAdapter;
            this.activity = activity;
        }

        private boolean canSwipe(RecyclerView.ViewHolder viewHolder){
            if(viewHolder instanceof ViewHolderSplite){
                return false;
            }else{
                return true;
            }
        }

        @Override
        public int getMovementFlags(@NonNull RecyclerView recyclerView, @NonNull RecyclerView.ViewHolder viewHolder) {
            if(canSwipe(viewHolder)){
                final int dragFlags = ItemTouchHelper.UP | ItemTouchHelper.DOWN |ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT;
                final int swipeFlags = 0;
                return makeMovementFlags(dragFlags, swipeFlags);
            }else{
                return makeMovementFlags(0, 0);
            }
        }

        @Override
        public boolean onMove(@NonNull RecyclerView recyclerView, @NonNull RecyclerView.ViewHolder viewHolder, @NonNull RecyclerView.ViewHolder target) {
            if(target instanceof ViewHolderSplite){
                return false;
            }
            recyclerView.getParent().requestDisallowInterceptTouchEvent(true);
            //得到当拖拽的viewHolder的Position
            int fromPosition = viewHolder.getAdapterPosition();
            //拿到当前拖拽到的item的viewHolder
            int toPosition = target.getAdapterPosition();

            if (fromPosition < toPosition) {
                //从前面到后面
                for (int i = fromPosition; i < toPosition; i++) {
                    if(isHeader(i + 1)){//如果与标题替换，跳过
                        Collections.swap(pictureBeans, i, i + 2);
                        i++;
                    }else{
                        Collections.swap(pictureBeans, i, i + 1);
                    }
                }
            } else {
                //从后面到前面
                for (int i = fromPosition; i > toPosition; i--) {
                    if(isHeader(i - 1)){//如果与标题替换，跳过
                        Collections.swap(pictureBeans, i, i - 2);
                        i--;
                    }else{
                        Collections.swap(pictureBeans, i, i - 1);
                    }
                }
            }

            // 通知Adapter数据项已移动
            recycleViewAdapter.notifyItemMoved(fromPosition, toPosition);

            Log.d("dddd"," fromPosition = "+fromPosition+" toPosition"+toPosition);
            return true;
        }

        private boolean isHeader(int index){
            if(pictureBeans.get(index).itemType == MenuInfo.ITEM_TYPE_SPLITE){
                return true;
            }
            return false;
        }



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

        }

        /**
         * 长按选中Item时修改颜色
         *
         * @param viewHolder
         * @param actionState
         */
        @RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
        @Override
        public void onSelectedChanged(RecyclerView.ViewHolder viewHolder, int actionState) {
            //if (actionState != ItemTouchHelper.ACTION_STATE_IDLE) {
            //viewHolder.itemView.setBackground(getDrawable(R.drawable.card_drag_selected));
            //}
            super.onSelectedChanged(viewHolder, actionState);
        }

        /**
         * 手指松开的时候还原颜色
         * @param recyclerView
         * @param viewHolder
         */
        @RequiresApi(api = Build.VERSION_CODES.M)
        @Override
        public void clearView(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
            super.clearView(recyclerView, viewHolder);
            //viewHolder.itemView.setBackground(getDrawable(R.drawable.card));
        }
    }

android