时间戳

首页 > 解决方案 > ItemTouchHelper.SimpleCallback onMove() 未触发

android - ItemTouchHelper.SimpleCallback onMove() 未触发

问题描述

我想在我的RecyclerView. 正如我发现的那样，实现这一点的最佳方法是将一个附加ItemTouchHelper到RecyclerView.

onSwiped()工作正常，但onMove()永远不会触发。

这就是我所做的：

EditIngredientsRecyclerViewAdapter premixableIngredientsAdapter = new EditIngredientsRecyclerViewAdapter(this, typeOfComponents);
        GridLayoutManager gridLayoutManager1 = new GridLayoutManager(getContext(), 1);
        recyclerView.setAdapter(premixableIngredientsAdapter);
        recyclerView.setLayoutManager(gridLayoutManager1);

        ItemTouchHelper.SimpleCallback simpleItemTouchCallback = new ItemTouchHelper.SimpleCallback(0, ItemTouchHelper.LEFT) {
            @Override
            public boolean onMove(@NonNull RecyclerView recyclerView, @NonNull RecyclerView.ViewHolder viewHolder, @NonNull RecyclerView.ViewHolder target) {
                Log.d(TAG, "onMove: ");
                return false;
            }

            @Override
            public void onSwiped(@NonNull RecyclerView.ViewHolder viewHolder, int direction) {
                Log.d(TAG, "onSwiped: ");
            }
        };

        ItemTouchHelper touchHelper = new ItemTouchHelper(simpleItemTouchCallback);
        touchHelper.attachToRecyclerView(recyclerView);

标签： androidandroid-recyclerviewitemtouchhelper

解决方案

我忘记了两件事：

**1。更新SimpleCallback到这个：

ItemTouchHelper.SimpleCallback simpleItemTouchCallback = new ItemTouchHelper.SimpleCallback(0, ItemTouchHelper.LEFT) {
            @Override
            public boolean onMove(@NonNull RecyclerView recyclerView, @NonNull RecyclerView.ViewHolder viewHolder, @NonNull RecyclerView.ViewHolder target) {
                // Notify Adapter of the moved item!
                recyclerView.getAdapter().notifyItemMoved(viewHolder.getAdapterPosition(), target.getAdapterPosition());
                return true;
            }

            @Override
            public void onSwiped(@NonNull RecyclerView.ViewHolder viewHolder, int direction) {
                // No swipe action
            }

            @Override
            public boolean isItemViewSwipeEnabled() {
                // Disable swipe (dont override this method or return true, if you want to have swipe)
                return false;
            }

            @Override
            public int getMovementFlags(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
                // Set movement flags to specify the movement direction
                // final int dragFlags = ItemTouchHelper.UP | ItemTouchHelper.DOWN | ItemTouchHelper.RIGHT | ItemTouchHelper.LEFT;  <-- for all directions
                // In this case only up and down is allowed
                final int dragFlags = ItemTouchHelper.UP | ItemTouchHelper.DOWN;
                final int swipeFlags = 0;
                return makeMovementFlags(dragFlags, swipeFlags);
            }
        };

特别重要的是覆盖getMovementFlags()以指定拖动方向并通知适配器移动的项目，就像我在onMove()

2.触发拖动itemTouchHelper.startDrag(viewHolderElement)：

我通过在 RecyclerViewAdapter 中创建一个小接口来做到这一点：

public interface OnStartDragListener {
        void onStartDrag(RecyclerView.ViewHolder holder);
    }

在创建适配器时传入一个新的 OnStartDragListenerElement，如下所示：

EditIngredientsRecyclerViewAdapter premixableIngredientsAdapter = new EditIngredientsRecyclerViewAdapter(this, typeOfComponents, new EditIngredientsRecyclerViewAdapter.OnStartDragListener() {
            @Override
            public void onStartDrag(RecyclerView.ViewHolder holder) {
                touchHelper.startDrag(holder);
                Log.d(TAG, "onStartDrag: ");
            }
        });

并调用onStartDrag(viewHolder)Touchlistener 在视图中放置一个按钮，如下所示：

holder.itemBinding.dragBtn.setOnTouchListener(new View.OnTouchListener() {
                @Override
                public boolean onTouch(View v, MotionEvent event) {
                    mOnStartDragListener.onStartDrag(holder);
                    return false;
                }
            });

我敢肯定，有更有效的实现，一旦有人在这里发布，我会接受它。但是，这至少使它对我有用。

推荐阅读