RecyclerView分割线

RecyclerView分割线可以通过设置ItemDecoration来实现。下面是一个示例代码：

首先，创建一个分割线的类，继承自RecyclerView.ItemDecoration：

public class DividerItemDecoration extends RecyclerView.ItemDecoration {
    private Drawable mDivider;

    public DividerItemDecoration(Context context) {
        // 获取系统默认的分割线Drawable
        TypedArray styledAttributes = context.obtainStyledAttributes(new int[]{android.R.attr.listDivider});
        mDivider = styledAttributes.getDrawable(0);
        styledAttributes.recycle();
    }

    @Override
    public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {
        int left = parent.getPaddingLeft();
        int right = parent.getWidth() - parent.getPaddingRight();

        int childCount = parent.getChildCount();
        for (int i = 0; i < childCount; i++) {
            View child = parent.getChildAt(i);

            RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child.getLayoutParams();

            int top = child.getBottom() + params.bottomMargin;
            int bottom = top + mDivider.getIntrinsicHeight();

            mDivider.setBounds(left, top, right, bottom);
            mDivider.draw(c);
        }
    }
}

然后，在使用RecyclerView的地方，添加分割线：

RecyclerView recyclerView = findViewById(R.id.recyclerView);
recyclerView.addItemDecoration(new DividerItemDecoration(this));

这样就可以在RecyclerView的每个Item之间添加一个默认的分割线了。如果需要自定义分割线的样式，可以修改DividerItemDecoration类中的绘制逻辑或者使用其他Drawable替代mDivider。