RecycleView没有设置分割线的方法。有两种方法可以实现分割线。一种方法是在Item中设置一个分割线（用过这个方法，这种方法实际上是非常麻烦的）。
另外是自定一个分割线（本文主要讲的）。
我实现这个效果之后找到一篇非常不错的博客：http://blog.csdn.net/pengkv/article/details/50538121
博客封装得不错，比自己写的半吊子要好，所以直接拿来使用并封装在了开发框架内。
使用方法
提供了三个构造函数，使用者可以使用默认的或者自定义样式。
//添加默认分割线：高度为2px，颜色为灰色
mRecyclerView.addItemDecoration(new RecycleViewDivider(mContext, LinearLayoutManager.VERTICAL));
//添加自定义分割线：可自定义分割线drawable
mRecyclerView.addItemDecoration(new RecycleViewDivider(
mContext, LinearLayoutManager.VERTICAL, R.drawable.divider_mileage));
//添加自定义分割线：可自定义分割线高度和颜色
mRecyclerView.addItemDecoration(new RecycleViewDivider(
mContext, LinearLayoutManager.VERTICAL, 10, getResources().getColor(R.color.divide_gray_color)));
万能分割线类
非常通用的类，可以根据自定项目中的需求修改样式。
不过这个源码是有个坑的，就是构造函数里面的this(context, orientation);使用的时候一定要注释或者删除。否则都是默认的效果！
public class RecycleViewDivider extends RecyclerView.ItemDecoration {
private Paint mPaint;
private Drawable mDivider;
private int mDividerHeight = 2;//分割线高度，默认为1px
private int mOrientation;//列表的方向：LinearLayoutManager.VERTICAL或LinearLayoutManager.HORIZONTAL
private static final int[] ATTRS = new int[]{android.R.attr.listDivider};
/**
* 默认分割线：高度为2px，颜色为灰色
*
* @param context
* @param orientation 列表方向
*/
public RecycleViewDivider(Context context, int orientation) {
if (orientation != LinearLayoutManager.VERTICAL && orientation != LinearLayoutManager.HORIZONTAL) {
throw new IllegalArgumentException("请输入正确的参数！");
}
mOrientation = orientation;
final TypedArray a = context.obtainStyledAttributes(ATTRS);
mDivider = a.getDrawable(0);
a.recycle();
}
/**
* 自定义分割线
*
* @param context
* @param orientation 列表方向
* @param drawableId 分割线图片
*/
public RecycleViewDivider(Context context, int orientation, int drawableId) {
//this(context, orientation);
mDivider = ContextCompat.getDrawable(context, drawableId);
mDividerHeight = mDivider.getIntrinsicHeight();
}
/**
* 自定义分割线
*
* @param context
* @param orientation 列表方向
* @param dividerHeight 分割线高度
* @param dividerColor 分割线颜色
*/
public RecycleViewDivider(Context context, int orientation, int dividerHeight, int dividerColor) {
//this(context, orientation);
mDividerHeight = dividerHeight;
mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
mPaint.setColor(dividerColor);
mPaint.setStyle(Paint.Style.FILL);
}
//获取分割线尺寸
@Override
public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
super.getItemOffsets(outRect, view, parent, state);
outRect.set(0, 0, 0, mDividerHeight);
}
//绘制分割线
@Override
public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {
super.onDraw(c, parent, state);
if (mOrientation == LinearLayoutManager.VERTICAL) {
drawVertical(c, parent);
} else {
drawHorizontal(c, parent);
}
}
//绘制横向 item 分割线
private void drawHorizontal(Canvas canvas, RecyclerView parent) {
final int left = parent.getPaddingLeft();
final int right = parent.getMeasuredWidth() - parent.getPaddingRight();
final int childSize = parent.getChildCount();
for (int i = 0; i < childSize; i++) {
final View child = parent.getChildAt(i);
RecyclerView.LayoutParams layoutParams = (RecyclerView.LayoutParams) child.getLayoutParams();
final int top = child.getBottom() + layoutParams.bottomMargin;
final int bottom = top + mDividerHeight;
if (mDivider != null) {
mDivider.setBounds(left, top, right, bottom);
mDivider.draw(canvas);
}
if (mPaint != null) {
canvas.drawRect(left, top, right, bottom, mPaint);
}
}
}
//绘制纵向 item 分割线
private void drawVertical(Canvas canvas, RecyclerView parent) {
final int top = parent.getPaddingTop();
final int bottom = parent.getMeasuredHeight() - parent.getPaddingBottom();
final int childSize = parent.getChildCount();
for (int i = 0; i < childSize; i++) {
final View child = parent.getChildAt(i);
RecyclerView.LayoutParams layoutParams = (RecyclerView.LayoutParams) child.getLayoutParams();
final int left = child.getRight() + layoutParams.rightMargin;
final int right = left + mDividerHeight;
if (mDivider != null) {
mDivider.setBounds(left, top, right, bottom);
mDivider.draw(canvas);
}
if (mPaint != null) {
canvas.drawRect(left, top, right, bottom, mPaint);
}
}
}
}
原文来自：http://blog.csdn.net/pengkv/article/details/50538121
向开源者致敬！
