很简单为RecyclerView添加头部：使用一个类RecyclerViewHeader

首先看下自己的RecyclerView是否包裹在 LinearLayout, FrameLayout, RelativeLayout.这三种布局中，否则会报错：

 Currently, NOT already aligned RecyclerViewHeader can only be used for RecyclerView with a parent of one of types: LinearLayout, FrameLayout, RelativeLayout.

意思就是说RecyclerViewHeader这个东西只使用在线性布局、帧布局、相对布局包裹下的RecyclerView

例如：

activity_main布局

<LinearLayout   

    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"    android:layout_height="match_parent">    <android.support.v7.widget.RecyclerView        android:id="@+id/recyclerview"        android:layout_width="match_parent"        android:layout_height="match_parent" />

</LinearLayout>

检查好上面的步骤之后，开始RecyclerViewHeader

1、首先在model层的build的dependencies中加入依赖：compile 'com.bartoszlipinski.recyclerviewheader:library:1.2.0'

dependencies {
    compile 'com.bartoszlipinski.recyclerviewheader:library:1.2.0'
}

为你的header创建一个XML布局文件：（就是你要加的头部的布局，我这里只加了一个TextView），这是一个单独的xml文件

1、创建一个布局文件

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="100dp">
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:text="header" />
</FrameLayout>

2、MainActivity代码

public class MainActivity extends AppCompatActivity implements MyRecyclerViewAdapter.onItemClickListener {
//声明RecyclerView
    private RecyclerView mRecyclerview;
    //数据源
    private List<String> list;
//声明Adapter
    MyRecyclerViewAdapter myRecyclerViewAdapter;
//声明RecyclerViewHeader对象
    RecyclerViewHeader header;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
//初始化RecyclerViewHeader
        header = RecyclerViewHeader.fromXml(this, R.layout.header);
mRecyclerview = (RecyclerView) findViewById(R.id.recyclerview);
        
        list = new ArrayList<>();
        for (int i = 0; i < 100; i++) {
            list.add("这是第" + i + "条");
        }
        myRecyclerViewAdapter = new MyRecyclerViewAdapter(list);
//使用RecyclerView一定要setLayoutManager
        mRecyclerview.setLayoutManager(new LinearLayoutManager(this));
//        mRecyclerview.setLayoutManager(new GridLayoutManager(this,2));
//        mRecyclerview.setLayoutManager(new StaggeredGridLayoutManager(3,StaggeredGridLayoutManager.HORIZONTAL));
        //把RecyclerViewHeader赋予RecyclerView,这个一定要写在setLayoutManager之后
	header.attachTo(mRecyclerview);
        mRecyclerview.setAdapter(myRecyclerViewAdapter);
        myRecyclerViewAdapter.setOnItemClickListener(this);
        
    }

    @Override
    public void onItemClick(View view, int position) {
        Log.d("TAG", "类名==MainActivity" + "方法名==onItemClick===:" + "当前点击的是第" + position);
    }

}
目前该库RecyclerViewHeader适用于LinearLayoutManager,GridLayoutManager和StaggeredGridLayoutManager布局的RecyclerView。