Android RecycleView添加head配置封装的实例

package com.wwl.android;  import android.support.v7.widget.GridLayoutManager; import android.support.v7.widget.RecyclerView; import android.support.v7.widget.StaggeredGridLayoutManager; import android.view.View; import android.view.ViewGroup;  import java.util.ArrayList;   public abstract class BaseRecyclerAdapter<T> extends RecyclerView.Adapter<RecyclerView.ViewHolder> {    public static final int TYPE_HEADER = 0;   public static final int TYPE_NORMAL = 1;    private ArrayList<T> mDatas = new ArrayList<>();    private View mHeaderView;    private OnItemClickListener mListener;    public void setOnItemClickListener(OnItemClickListener li) {     mListener = li;   }    public void setHeaderView(View headerView) {     mHeaderView = headerView;     notifyItemInserted(0);   }    public View getHeaderView() {     return mHeaderView;   }    public void addDatas(ArrayList<T> datas) {     mDatas.addAll(datas);     notifyDataSetChanged();   }    @Override   public int getItemViewType(int position) {     if(mHeaderView == null) return TYPE_NORMAL;     if(position == 0) return TYPE_HEADER;     return TYPE_NORMAL;   }    @Override   public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, final int viewType) {     if(mHeaderView != null && viewType == TYPE_HEADER) return new Holder(mHeaderView);     return onCreate(parent, viewType);   }     @Override   public void onBindViewHolder(RecyclerView.ViewHolder viewHolder, int position) {     if(getItemViewType(position) == TYPE_HEADER) return;      final int pos = getRealPosition(viewHolder);     final T data = mDatas.get(pos);     onBind(viewHolder, pos, data);      if(mListener != null) {       viewHolder.itemView.setOnClickListener(new View.OnClickListener() {         @Override         public void onClick(View v) {           mListener.onItemClick(pos, data);         }       });     }   }    @Override   public void onAttachedToRecyclerView(RecyclerView recyclerView) {     super.onAttachedToRecyclerView(recyclerView);      RecyclerView.LayoutManager manager = recyclerView.getLayoutManager();     if(manager instanceof GridLayoutManager) {       final GridLayoutManager gridManager = ((GridLayoutManager) manager);       gridManager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {         @Override         public int getSpanSize(int position) {           return getItemViewType(position) == TYPE_HEADER               ? gridManager.getSpanCount() : 1;         }       });     }   }    @Override   public void onViewAttachedToWindow(RecyclerView.ViewHolder holder) {     super.onViewAttachedToWindow(holder);     ViewGroup.LayoutParams lp = holder.itemView.getLayoutParams();     if(lp != null         && lp instanceof StaggeredGridLayoutManager.LayoutParams         && holder.getLayoutPosition() == 0) {       StaggeredGridLayoutManager.LayoutParams p = (StaggeredGridLayoutManager.LayoutParams) lp;       p.setFullSpan(true);     }   }    public int getRealPosition(RecyclerView.ViewHolder holder) {     int position = holder.getLayoutPosition();     return mHeaderView == null ? position : position - 1;   }    @Override   public int getItemCount() {     return mHeaderView == null ? mDatas.size() : mDatas.size() + 1;   }    public abstract RecyclerView.ViewHolder onCreate(ViewGroup parent, final int viewType);   public abstract void onBind(RecyclerView.ViewHolder viewHolder, int RealPosition, T data);    public class Holder extends RecyclerView.ViewHolder {     public Holder(View itemView) {       super(itemView);     }   }    public interface OnItemClickListener<T> {     void onItemClick(int position, T data);   } } 

package com.wwl.android;  import android.support.v7.widget.RecyclerView; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.TextView;  /**  * wwl  */ public class MyAdapter extends BaseRecyclerAdapter<String> {    @Override   public RecyclerView.ViewHolder onCreate(ViewGroup parent, int viewType) {     View layout = LayoutInflater.from(parent.getContext()).inflate(R.layout.item, parent, false);     return new MyHolder(layout);   }    @Override   public void onBind(RecyclerView.ViewHolder viewHolder, int RealPosition, String data) {     if(viewHolder instanceof MyHolder) {       ((MyHolder) viewHolder).text.setText(data);     }   }    class MyHolder extends BaseRecyclerAdapter.Holder {     TextView text;     public MyHolder(View itemView) {       super(itemView);       text = (TextView) itemView.findViewById(R.id.text);     }   } }  

public class MainActivity extends AppCompatActivity {    private RecyclerView mRecyclerView;   private RecyclerView.LayoutManager mLayoutManager;   private MyAdapter mAdapter;    @Override   protected void onCreate(Bundle savedInstanceState) {     super.onCreate(savedInstanceState);     setContentView(R.layout.activity_main);      mRecyclerView = (RecyclerView) findViewById(R.id.list); //    mLayoutManager = new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false);     mLayoutManager = new GridLayoutManager(this, 2); //    mLayoutManager = new StaggeredGridLayoutManager(2, StaggeredGridLayoutManager.VERTICAL);     mRecyclerView.setLayoutManager(mLayoutManager);     mRecyclerView.setItemAnimator(new DefaultItemAnimator());     mRecyclerView.addItemDecoration(new GridItemDecoration(this, true));      mAdapter = new MyAdapter();     mRecyclerView.setAdapter(mAdapter);     mAdapter.addDatas(generateData());     setHeader(mRecyclerView);     mAdapter.setOnItemClickListener(new BaseRecyclerAdapter.OnItemClickListener<String>() {       @Override       public void onItemClick(int position, String data) {         Toast.makeText(MainActivity.this, position + "," + data, Toast.LENGTH_SHORT).show();       }     });   }    private void setHeader(RecyclerView view) {     View header = LayoutInflater.from(this).inflate(R.layout.header, view, false);          mAdapter.setHeaderView(header);   }    private ArrayList<String> generateData() {     ArrayList<String> data = new ArrayList<String>() {       {         for(int i=0;i<21;i++) add("数据" + i);       }     };     return data;   }    } 

<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"   xmlns:tools="http://schemas.android.com/tools"   android:layout_width="match_parent"   android:layout_height="match_parent">    <android.support.v7.widget.RecyclerView     android:id="@+id/list"     android:layout_width="match_parent"     android:layout_height="match_parent" />  </LinearLayout> 

<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"   android:layout_width="match_parent"   android:layout_height="wrap_content"   android:orientation="vertical">    <ImageView     android:layout_gravity="center_horizontal"     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:src="@mipmap/ic_launcher"/>  </LinearLayout> 

<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"   android:layout_width="match_parent"   android:layout_height="wrap_content"   android:padding="20dp"   android:orientation="vertical">    <TextView     android:id="@+id/text"     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:layout_centerInParent="true"     android:text="数据"/>  </RelativeLayout>