如何在RecyclerView元素之间以及元素内部绘制垂直线？

public class VerticalLineDecoration extends RecyclerView.ItemDecoration {
    private Paint mPaint;

    public VerticalLineDecoration(int color, int width) {
        mPaint = new Paint();
        mPaint.setColor(color);
        mPaint.setStrokeWidth(width);
    }

    @Override
    public void onDrawOver(Canvas c, RecyclerView parent, RecyclerView.State state) {
        int childCount = parent.getChildCount();
        for (int i = 0; i < childCount; i++) {
            View child = parent.getChildAt(i);
            int left = child.getLeft();
            int top = child.getBottom();
            int right = child.getRight();
            int bottom = top + 1; // 设置线的高度
            c.drawLine(left, top, right, bottom, mPaint);
        }
    }
}

RecyclerView recyclerView = findViewById(R.id.recycler_view);
recyclerView.addItemDecoration(new VerticalLineDecoration(Color.BLACK, 2));