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android - 滑动时的 RecyclerView ItemTouchHelper

问题描述

我正在尝试在回收站视图中实现滑动删除。我有这个代码。

public abstract class SwipeToDeleteCallback extends ItemTouchHelper.Callback {
    private Context context;
    private Paint clearPaint;
    private ColorDrawable background;
    private int backgroundColor;
    private Drawable deleteDrawable;
    private int intrinsicWidth;
    private int intrinsicHeight;

    public SwipeToDeleteCallback(Context context) {
        this.context = context;
        background = new ColorDrawable();
        backgroundColor = Color.parseColor("#DB3236");
        clearPaint = new Paint();
        clearPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.CLEAR));
        deleteDrawable = ContextCompat.getDrawable(this.context, R.drawable.ic_delete_white_24dp);
        intrinsicWidth = deleteDrawable.getIntrinsicWidth();
        intrinsicHeight = deleteDrawable.getIntrinsicHeight();
    }

    @Override
    public int getMovementFlags(@NonNull RecyclerView recyclerView,
                                @NonNull RecyclerView.ViewHolder viewHolder) {
        return makeMovementFlags(0, ItemTouchHelper.LEFT);
    }

    @Override
    public boolean onMove(@NonNull RecyclerView recyclerView,
                          @NonNull RecyclerView.ViewHolder viewHolder,
                          @NonNull RecyclerView.ViewHolder viewHolder1) {
        return false;
    }

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

        View itemView = viewHolder.itemView;
        int itemHeight = itemView.getHeight();

        boolean isCancelled = dX == 0 && !isCurrentlyActive;

        if (isCancelled) {
            clearCanvas(canvas, itemView.getRight() + dX, (float) itemView.getTop(),
                    (float) itemView.getRight(), (float) itemView.getBottom());
            super.onChildDraw(canvas, recyclerView, viewHolder, dX, dY, actionState,
                    isCurrentlyActive);
            return;
        }

        background.setColor(backgroundColor);
        background.setBounds(itemView.getRight() + (int) dX, itemView.getTop(),
                itemView.getRight(), itemView.getBottom());
        background.draw(canvas);

        int deleteIconTop = itemView.getTop() + (itemHeight - intrinsicHeight) / 2;
        int deleteIconMargin = (itemHeight - intrinsicHeight) / 2;
        int deleteIconLeft = itemView.getRight() - deleteIconMargin - intrinsicWidth;
        int deleteIconRight = itemView.getRight() - deleteIconMargin;
        int deleteIconBottom = deleteIconTop + intrinsicHeight;

        deleteDrawable.setBounds(deleteIconLeft, deleteIconTop, deleteIconRight, deleteIconBottom);
        deleteDrawable.draw(canvas);

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

    private void clearCanvas(Canvas canvas, Float left, Float top, Float right, Float bottom) {
        canvas.drawRect(left, top, right, bottom, clearPaint);
    }

    @Override
    public float getSwipeThreshold(@NonNull RecyclerView.ViewHolder viewHolder) {
        return 0.7f;
    }
}

但是，问题是该行在滑动时被删除。我想将它保留在那里，即当滑动该行时，显示删除按钮，然后用户可以单击它，而不是滑动完全删除它，而是在滑动后显示删除按钮。另外，我也在尝试添加编辑按钮，但在左侧，删除，有什么想法吗？

标签： androidandroid-recyclerviewitemtouchhelper

解决方案

我发现这种实现滑动删除的新方法非常友好，即在 oncreate 方法中实现 new ItemTouchHelper()。您所要做的就是在 recyclevew 中传递要删除的项目的位置。请参阅下面的示例代码。在这里我实现了新的 ItemTouchHelper() 以删除我在屏幕上向右或向左滑动的任何笔记。

这是代码：

new ItemTouchHelper(new ItemTouchHelper.SimpleCallback(0,
            ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT) {
        @Override
        public boolean onMove(@NonNull RecyclerView recyclerView, @NonNull RecyclerView.ViewHolder viewHolder, @NonNull RecyclerView.ViewHolder viewHolder1) {
            return false;
        }

        @Override
        public void onSwiped(@NonNull RecyclerView.ViewHolder viewHolder, int i) {
            noteViewModel.delete(noteAdapter.getNoteAt(viewHolder.getAdapterPosition()));
            Toast.makeText(MainActivity.this, "Note Deleted", Toast.LENGTH_SHORT).show();
        }
    }).attachToRecyclerView(rv_notes);

rv_notes 是我的 recyclerview 的实例

要了解如何清楚地实现它，请按照我的 github 中的代码进行操作。这里是链接。 https://github.com/sammymutahigicheru/NoteApp

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