如何让RecyclerView内侧抽屉？

public class DrawerItemDecoration extends RecyclerView.ItemDecoration {
    private Drawable drawer;
    private int drawerWidth;

    public DrawerItemDecoration(Context context, @DrawableRes int drawerResId, int drawerWidth) {
        drawer = ContextCompat.getDrawable(context, drawerResId);
        this.drawerWidth = drawerWidth;
    }

    @Override
    public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {
        super.onDraw(c, parent, state);

        int childCount = parent.getChildCount();
        for (int i = 0; i < childCount; i++) {
            View child = parent.getChildAt(i);
            int left = child.getRight();
            int right = left + drawerWidth;
            int top = child.getTop();
            int bottom = child.getBottom();
            drawer.setBounds(left, top, right, bottom);
            drawer.draw(c);
        }
    }
}

RecyclerView recyclerView = findViewById(R.id.recyclerView);
recyclerView.addItemDecoration(new DrawerItemDecoration(this, R.drawable.drawer, drawerWidth));