ItemTouchHelper :限制ItemTouchHelper.SimpleCallBack在RecyclerView上的滑动宽度

Question

我已经成功地实现了滑动行为，并使用它执行了一些操作。现在的问题是，当我滑动项目时，我想限制滑动宽度。

目前正在发生的事情就是这样

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但我想把刷卡行为的宽度限制到这里

​

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这就是我迄今为止所做的:-

private void swipeExample(){
        ItemTouchHelper.SimpleCallback simpleItemTouchCallback = new ItemTouchHelper.SimpleCallback(0, ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT) {

            @Override
            public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {
//                final int fromPos = viewHolder.getAdapterPosition();
//                final int toPos = target.getAdapterPosition();
                return false;
            }

            @Override
            public void onSwiped(final RecyclerView.ViewHolder viewHolder, int swipeDir) {

                // Show delete confirmation if swipped left
                if (swipeDir == ItemTouchHelper.LEFT) {

                    AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
                    builder.setMessage("Are you sure you want to delete?")
                            .setCancelable(false)
                            .setPositiveButton("Yes", new DialogInterface.OnClickListener() {
                                public void onClick(DialogInterface dialog, int id) {
                                    deleteItem(viewHolder);
//                                    getActivity().finish();
                                }
                            })
                            .setNegativeButton("No", new DialogInterface.OnClickListener() {
                                public void onClick(DialogInterface dialog, int id) {
                                    dialog.cancel();
                                }
                            });
                    AlertDialog alert = builder.create();
                    alert.show();

                } else if (swipeDir == ItemTouchHelper.RIGHT) {
                    // Show edit dialog
                }
            }

            @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 width = height / 3;

                    if (dX > 0) {
                        p.setColor(Color.parseColor("#388E3C"));
                        RectF background = new RectF((float) itemView.getLeft(), (float) itemView.getTop(), dX, (float) itemView.getBottom());
                        c.drawRect(background, p);
                        icon = BitmapFactory.decodeResource(getResources(), R.drawable.ic_mode_edit_white_24dp);
                        RectF icon_dest = new RectF((float) itemView.getLeft() + width, (float) itemView.getTop() + width, (float) itemView.getLeft() + 2 * width, (float) itemView.getBottom() - width);
                        c.drawBitmap(icon, null, icon_dest, p);
                    } else if (dX < 0) {
                        p.setColor(Color.parseColor("#D32F2F"));
                        RectF background = new RectF((float) itemView.getRight() + dX, (float) itemView.getTop(), (float) itemView.getRight(), (float) itemView.getBottom());
                        c.drawRect(background, p);
                        icon = BitmapFactory.decodeResource(getResources(), R.drawable.ic_delete_white_24dp);
                        RectF icon_dest = new RectF((float) itemView.getRight() - 2 * width, (float) itemView.getTop() + width, (float) itemView.getRight() - width, (float) itemView.getBottom() - width);
                        c.drawBitmap(icon, null, icon_dest, p);
                    }
                }
                super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
            }
        };

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

    }

请告诉我如何限制onChildDraw()方法的宽度。

提前谢谢。

Answer 1

最后，您的onChildDraw()方法调用其超级超级方法，如下所示：

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

要限制刷卡的最大宽度，可以使用减少的super.onChildDraw()来调用dX。

super.onChildDraw(c, recyclerView, viewHolder, dX / 4, dY, actionState, isCurrentlyActive);