mMenuView.setCutLineLeftPadding(30);
mMenuView.setCutLineRightPadding(30);
mMenuView.setGapLineColor(getResources().getColor(R.color.theme_bg));

MenuBean h=new MenuBean();
//或者直接指定rootView
h.type=R.layout.head_user;
h.menu="美其名曰美";
h.info="天道有常，不為堯存，不為桀亡。";
mMenuView.addMenu(5,h);
mMenuView.addGap(30);
addMenu(11,R.mipmap.ic1,"菜單一","新年新氣象",true);
addMenu(12,R.mipmap.ic2,"菜單二","",false);
addMenu(13,R.mipmap.ic3,"菜單三","發(fā)現(xiàn)更好的自己",false);
mMenuView.addGap(30);
addMenu(14,R.mipmap.ic4,"菜單四","",true);
addMenu(15,R.mipmap.ic5,"菜單五","",true);
mMenuView.addGap(30);
addMenu(16,R.mipmap.ic6,"菜單六","",true);
addMenu(17,R.mipmap.ic7,"菜單七","",false);
addMenu(18,R.mipmap.ic8,"菜單八","開(kāi)心才是最重要的",true);

class MenuDecoration extends RecyclerView.ItemDecoration{

 //onDraw在每次重繪時(shí)都會(huì)調(diào)用，比如滑動(dòng)RecyclerView
 //gap線(xiàn)為從左到右的完整線(xiàn)條，在最開(kāi)始的item上，最后的item下，或者空白區(qū)域的上下
 //cut線(xiàn)為兩個(gè)緊密挨著的兩個(gè)item之間的線(xiàn)條
 @Override
 public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {
  super.onDraw(c, parent, state);
  //當(dāng)?shù)谝粋€(gè)Item可見(jiàn)的時(shí)候，給第一個(gè)Item頂上繪一條Gap線(xiàn)
  //不用完整可見(jiàn)才繪制，考慮設(shè)置paddingTop+clipPadding=false的情況
  if(mLayout.findFirstVisibleItemPosition()==0){
   int bottom=parent.getChildAt(0).getTop();
   paint.setColor(gapLineColor);
   c.drawLine(parent.getLeft(),bottom-halfLineHeight,parent.getRight(),bottom-halfLineHeight,paint);
  }
  int count=parent.getChildCount();
  int gap;
  int end=mData.size()-1;
  //所有可見(jiàn)的Item下面畫(huà)線(xiàn)
  for (int i=0;i<count;i++){
   final View child = parent.getChildAt(i);
   int position=mLayout.getPosition(child);
   gap=mGap.get(position);
   float startY=child.getBottom()+halfLineHeight;
   //View下面不存在gap且不是最好一個(gè)Item的時(shí)候，繪制Cut線(xiàn)，否則繪制gap線(xiàn)
   if(gap==0&&position!=end){ 
    //繪制cut線(xiàn)的左邊線(xiàn)條
    if(leftPaddingLine!=0){
     paint.setColor(foreLineColor);
     c.drawLine(parent.getLeft(),startY,parent.getLeft()+leftPaddingLine,startY,paint);
    }
    //繪制cut線(xiàn)的右邊線(xiàn)條
    if(rightPaddingLine!=0){
     paint.setColor(foreLineColor);
     c.drawLine(parent.getRight()-rightPaddingLine,startY,parent.getRight(),startY,paint);
    }
    //繪制cut線(xiàn)的中間線(xiàn)條
    paint.setColor(cutLineColor);
    c.drawLine(parent.getLeft()+leftPaddingLine,startY,parent.getRight()-rightPaddingLine,startY,paint);
   }else{
    paint.setColor(gapLineColor);
    //繪制gap上面的一條線(xiàn)
    c.drawLine(parent.getLeft(),child.getBottom()+halfLineHeight,parent.getRight(),child.getBottom()+halfLineHeight,paint);
    //如果不是最后一個(gè)item，繪制gap下面的一條線(xiàn)
    if(position<end){
     c.drawLine(parent.getLeft(),child.getBottom()+gap+halfLineHeight,parent.getRight(),child.getBottom()+gap+halfLineHeight,paint);
    }
   }
  }
 }

 //在每個(gè)item加載時(shí)調(diào)用，用來(lái)判斷設(shè)置每個(gè)item上下左邊的空白區(qū)域，設(shè)置內(nèi)容分別設(shè)置到outRect中
 @Override
 public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
  super.getItemOffsets(outRect, view, parent, state);
  int position=mLayout.getPosition(view);
  //如果是第一個(gè)Item，則設(shè)置上線(xiàn)條高度，否則不設(shè)置上線(xiàn)條高度
  //為每個(gè)item設(shè)置下邊線(xiàn)條+gap(如果有的話(huà)，沒(méi)有就為0)的高度
  //四個(gè)參數(shù)分別為左邊空白區(qū)域，上方空白區(qū)域，右邊空白區(qū)域，下方空白區(qū)域
  outRect.set(0, position != 0 ? 0 : (int)(halfLineHeight * 2+0.5f),0,(int)(halfLineHeight*2+0.5f)+mGap.get(position));
 }
}

public void addGap(int height){
 mGap.put(mData.size()-1,height);
}