向左滑动即可在回收者视图项目中的卡片视图顶部显示视图

Question

在“回收者”视图的子项上向左滑动以显示自定义视图
result_what_i_get
needed_result
我使用了以下代码：

 ItemTouchHelper.SimpleCallback simpleCallback = new ItemTouchHelper.SimpleCallback(0, ItemTouchHelper.LEFT) {
    @Override
    public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {
        return false;
    }

    @Override
    public void onSwiped(final RecyclerView.ViewHolder viewHolder, int direction) {
        final int position = viewHolder.getAdapterPosition();
        if (direction == ItemTouchHelper.LEFT) {
            Toast.makeText(getApplicationContext(), "Left swipe at position :"+(position+1), Toast.LENGTH_SHORT).show();
        }
    }

    @Override
    public void onChildDraw(Canvas c, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive) {
        try {
            if (actionState == ItemTouchHelper.ACTION_STATE_SWIPE) {
                View itemView = viewHolder.itemView;
                Paint paint = new Paint();
                paint.setColor(Color.parseColor("#D32F2F"));
                RectF background = new RectF((float) itemView.getRight() + dX / 5, (float) itemView.getTop(), (float) itemView.getRight(), (float) itemView.getBottom());
                c.drawRect(background, paint);
            } else {
                super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
};
ItemTouchHelper itemTouchHelper = new ItemTouchHelper(simpleCallback);
itemTouchHelper.attachToRecyclerView(recyclerView);

但是我得到以下结果：result_what_i_get
但我需要该结果：needed_result

  

项目xml文件

我在上面的代码中使用的自定义项目文件：

<android.support.v7.widget.CardView
    android:id="@+id/cardV"
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    app:cardBackgroundColor="@android:color/white"
    app:cardCornerRadius="3dp"
    app:cardElevation="4dp"
    android:layout_marginTop="4dp"
    android:layout_marginLeft="4dp"
    android:layout_marginRight="4dp"
    app:cardUseCompatPadding="true"
    app:contentPadding="10dp">

    <LinearLayout
        android:id="@+id/mainLayout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical">

        <TextView
            android:id="@+id/card_view_label"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:padding="10dp"
            android:textColor="@android:color/black"
            android:textSize="15sp" />

        <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:gravity="center"
            android:padding="5dp"
            android:text="Swipe"
            android:textColor="@android:color/darker_gray"
            android:textSize="12sp" />
    </LinearLayout>
</android.support.v7.widget.CardView>

向左滑动即可显示一个视图，就像我在屏幕截图中提到的一样