Question

我有一个RecyclerView，刷完后应删除这些项目。我用ItemTouchHelper类解决了它。在onChildDraw方法中，我设置了一个红色背景，在刷新列表项后面时出现。最重要的是，右侧网站上有一个垃圾桶图标。它工作正常，但是如果你开始滑动并且不要滑到最后然后再刷回到正常位置，垃圾的图标就不会消失。但是，当我滑动所选项目时，它只会消失，而不是正常项目。

以下是ItemTouchHelper类的代码：

ItemTouchHelper.SimpleCallback simpleItemTouchCallback = new ItemTouchHelper.SimpleCallback(0, ItemTouchHelper.LEFT) {

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

        @Override
        public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {
            int position = viewHolder.getAdapterPosition();
            rvAdapter.removeItem(position);
        }

        @Override
        public void onChildDraw(Canvas c, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive){

            Bitmap icon;
            if(actionState == ItemTouchHelper.ACTION_STATE_SWIPE){

                View itemView = viewHolder.itemView;
                float height = (float) itemView.getBottom() - (float) itemView.getTop();
                float marginRight = 10;

                paint.setColor(Color.parseColor("#D32F2F"));
                RectF background = new RectF((float) itemView.getRight() + dX, (float) itemView.getTop(),(float) itemView.getRight(), (float) itemView.getBottom());
                c.drawRect(background,paint);
                icon = BitmapFactory.decodeResource(getResources(), R.drawable.ic_delete_forever);
                RectF icon_dest = new RectF((float) itemView.getRight() - marginRight - height, itemView.getTop(), itemView.getRight() - marginRight, itemView.getBottom());
                c.drawBitmap(icon,null,icon_dest,paint);

            }

            super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);

        }

    };

有人知道如何在取消滑动时删除图标？还是有类似z-index的东西？因为当我向后滑动所选项目时，垃圾桶图标会在项目下消失。但是当我刷一个普通项目时，图标就在项目上方，然后图标就会停留在那里。

Answer 1

@Override
    public void onChildDraw(Canvas c, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive) {
        if (actionState == ItemTouchHelper.ACTION_STATE_SWIPE) {
            Bitmap icon;
            Paint paint = new Paint();

            View itemView = viewHolder.itemView;
            float height = (float) itemView.getBottom() - (float) itemView.getTop();
            float width = height / 3;

            if (dX < 0) {
                paint.setColor(Color.parseColor("#D32F2F"));

                RectF background = new RectF(
                        (float) itemView.getRight() + dX, (float) itemView.getTop(),
                        (float) itemView.getRight(), (float) itemView.getBottom());
                c.drawRect(background, paint);

                icon = BitmapFactory.decodeResource(context.getResources(), R.drawable.ic_delete);
                RectF iconDest = new RectF(
                        (float) itemView.getRight() - 2 * width, (float) itemView.getTop() + width,
                        (float) itemView.getRight() - width, (float) itemView.getBottom() - width);
                c.drawBitmap(icon, null, iconDest, paint);
            }

        } else if (actionState == ItemTouchHelper.ACTION_STATE_DRAG) {
            final float alpha = ALPHA_FULL - Math.abs(dY) / (float) viewHolder.itemView.getHeight();
            viewHolder.itemView.setAlpha(alpha);
            viewHolder.itemView.setTranslationY(dY);
        }

        super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
    }

Android - RecyclerView：使用滑动删除项目

1 个答案: