RecyclerView-->分割线

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使用RecyclerView，添加分割线的方式有以下两种：

• 在item布局中添加；
• 使用RecyclerView的addItemDecoration(ItemDecoration fromHtml)方法，我们需要自定义ItemDecoration。

第一种就不说了，我们直接看第二种的实现。
自定义一个继承自ItemDecoraton的类，如下：

public class RvItemDecoration extends RecyclerView.ItemDecoration {

    private final Paint mPaint;

    public RvItemDecoration(int color){
        mPaint = new Paint();
        mPaint.setColor(color);
        mPaint.setAntiAlias(true);
    }
    @Override
    public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {
        int childCount = parent.getChildCount();
        //获取需要绘制的区域
        Rect rect = new Rect();
        rect.left = parent.getPaddingLeft();
        rect.right = parent.getWidth() - parent.getPaddingRight();
        for (int i = 0; i < childCount; i++) {
            View childView = parent.getChildAt(i);
            rect.top = childView.getBottom();
            rect.bottom = rect.top + 20;
            c.drawRect(rect,mPaint);
        }
    }

    /**
     * 确定分割线的高度或者说是画在什么位置
     * @param outRect
     * @param view
     * @param parent
     * @param state
     */
    @Override
    public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
        //在每个子view的下面留出20px来画分割线
        outRect.bottom +=20;
    }
}

对应的效果图：

我们也可以使用系统默认的分割线DividerItemDecoration，

mRecyclerView.addItemDecoration(new DividerItemDecoration(this, LinearLayoutManager.VERTICAL));

也可以利用Drawable

        DividerItemDecoration dividerItemDecoration = new DividerItemDecoration(this, LinearLayoutManager.VERTICAL);
        dividerItemDecoration.setDrawable(getResources().getDrawable(R.drawable.line));
        mRecyclerView.addItemDecoration(dividerItemDecoration);