首先需要添加进来

com.android.support:recyclerview-v7:28.0.0-beta01

源码实现

eg：

LuffyRecycler：

@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.recycler_layout);

    RecyclerView recyclerView=findViewById(R.id.recyclerView);
    recyclerView.setLayoutManager(new LinearLayoutManager(this));
    RecyclerAdapter adapter=new RecyclerAdapter(this);
    recyclerView.setAdapter(adapter);
}

RecyclerAdapter：

import android.content.Context;
import android.support.annotation.NonNull;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import io.github.grooters.luffy.R;

private class InerHolder extends RecyclerView.ViewHolder{
    private TextView textView;
    private InerHolder(@NonNull View itemView) {
        super(itemView);
        textView=itemView.findViewById(R.id.recycler_textView);
    }
}
private class RecyclerAdapter extends RecyclerView.Adapter {
    private Context context;
    public RecyclerAdapter(Context context) {
        super();
        this.context=context;
    }
    @NonNull
    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
        return new InerHolder(LayoutInflater.from(context).inflate(R.layout.recycler_item,viewGroup,false));
    }
    @Override
    public void onBindViewHolder(@NonNull RecyclerView.ViewHolder viewHolder, int i) {
        //此处若不想转型，可按第二种写法创建Adapter
        ((InerHolder)viewHolder).textView.setText("i:"+i);
    }
    @Override
    public long getItemId(int position) {
        return super.getItemId(position);
    }
    @Override
    public int getItemCount() {
        //输出一个Item
        return 1;
    }
}

第二种Adapter写法（详见泛型）：
LuffyRecycler：

private class InerHolder extends RecyclerView.ViewHolder{
    private TextView textView;
    private InerHolder(@NonNull View itemView) {
        super(itemView);
        textView=findViewById(R.id.recycler_textView);
    }
}
private class InerAdapter extends RecyclerView.Adapter<InerHolder>{
    @NonNull
    @Override
    public InerHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
        return new InerHolder(LayoutInflater.from(getApplicationContext()).inflate(R.layout.recycler_item,viewGroup,false));
    }
    @Override
    public void onBindViewHolder(@NonNull InerHolder inerHolder, int i) {
        inerHolder.textView.setText("i:"+i);
    }
    @Override
    public int getItemCount() {
        return 1;
    }
    @Override
    public long getItemId(int position) {
        return super.getItemId(position);
    }
}

RecyclerView的滚动事件

RecyclerView有两种滚动状态：

静止 -> 被迫拖拽移动 -> 静止
静止 -> 被迫拖拽移动 -> 自己滚动 -> 静止

在滚动过程中，会回调两个方法：

onScrollStateChanged

滚动状态变化时

onScrolled

滚动时

eg:

recycler.addOnScrollListener(new RecyclerView.OnScrollListener() {
    @Override
    public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
        super.onScrollStateChanged(recyclerView, newState);
        Log.i(TAG, "onScrollStateChanged");
        //目前的状态
        Log.i(TAG, "newState: " + newState);
    }
    @Override
    public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
        super.onScrolled(recyclerView, dx, dy);
        Log.i(TAG, "onScrolled");
        //水平滚动距离
        Log.i(TAG, "dx: " + dx);
        //垂直滚动距离
        Log.i(TAG, "dy: " + dy);
        Log.i(TAG, "CHECK_SCROLL_UP: " + recyclerView.canScrollVertically(TAG_CHECK_SCROLL_UP));
        Log.i(TAG, "CHECK_SCROLL_DOWN: " + recyclerView.canScrollVertically(TAG_CHECK_SCROLL_DOWN));
    }
});

newState:

public static final int SCROLL_STATE_IDLE = 0; //停止滚动
public static final int SCROLL_STATE_DRAGGING = 1; //正在被外部拖拽,一般为用户正在用手指滚动
public static final int SCROLL_STATE_SETTLING = 2; //自动滚动开始

点击事件

private class StudentViewHolder extends RecyclerView.ViewHolder{
    private TextView textViewId,textViewName,textViewDepartment;
    private ImageView imageView;
    private StudentViewHolder(@NonNull View itemView) {
        super(itemView);
        itemView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                //adapter.notifyItemChanged(1,1);
                adapter.notifyItemChanged(1);
                Log.i(TAG,"onClick");
            }
        });
        imageView=itemView.findViewById(R.id.img);
        textViewId=itemView.findViewById(R.id.textView_id);
        textViewName=itemView.findViewById(R.id.textVew_name);
        textViewDepartment=itemView.findViewById(R.id.textView_department);
    }
}

void notifyItemChanged (int position)

更新指定行

void notifyItemChanged (int position, Object payload)

payload只需传入任意值

更新position行，可防止图片闪现,配合以下使用：

public void onBindViewHolder(@NonNull StudentViewHolder holder, int position, @NonNull List

@Override
public void onBindViewHolder(@NonNull StudentViewHolder studentViewHolder, int i) {
    Log.i(TAG,"onBindViewHolder");
    studentViewHolder.textViewId.setText(students.get(i).getId());
    studentViewHolder.textViewName.setText(students.get(i).getName());
    studentViewHolder.textViewDepartment.setText(students.get(i).getDepartment());
}
@Override
public void onBindViewHolder(@NonNull StudentViewHolder holder, int position, @NonNull List<Object> payloads) {
    super.onBindViewHolder(holder, position, payloads);
    if(payloads.isEmpty()){
        onBindViewHolder(holder,position);
    }else{
        holder.textViewId.setText("haha:"+position);
        holder.textViewName.setText(students.get(position).getName());
        holder.textViewDepartment.setText(students.get(position).getDepartment());
    }
}

其它常用方法

1 2	//从位置0移动到5 recyclerView.getAdapter().notifyItemMoved(0,5)

RecyclerView的封装

第一次拙劣(错误)的封装

源码如下：

public class RecyclerWidget extends RecyclerView {
    private static final String TAG=RecyclerWidget.class.getSimpleName();
    private Context context;
    private int viewId;
    private RecyclerMethodInterface recyclerMethodInterface;
    public RecyclerWidget(@NonNull Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
        Log.i(TAG,"RecyclerWidget");
    }
    public void initRecycler(Context context, int vireId){
        Log.i(TAG,"initRecycler:"+vireId);
        this.context=context;
        this.viewId=vireId;
    }

    public RecyclerAdapter setRecyclerAdapter(RecyclerMethodInterface recyclerMethodInterface){
        this.recyclerMethodInterface=recyclerMethodInterface;
        RecyclerAdapter adapter=new RecyclerAdapter();
        //注意不能漏掉这句
        setLayoutManager(new LinearLayoutManager(context));
        Log.i(TAG,"setRecyclerAdapter");
        setAdapter(adapter);
        return adapter;
    }
    private class InnerHolder extends ViewHolder{
        private InnerHolder(@NonNull View itemView) {
            super(itemView);
            Log.i(TAG,"InnerHolder");
        }
    }
    public class RecyclerAdapter extends Adapter{
        @NonNull
        @Override
        public ViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
            Log.i(TAG,"onCreateViewHolder");
            return new InnerHolder(LayoutInflater.from(context).inflate(viewId,viewGroup,false));
        }
        @Override
        public void onBindViewHolder(@NonNull ViewHolder viewHolder, int i) {
            Log.i(TAG,"onBindViewHolder");
            if(recyclerMethodInterface!=null){
                recyclerMethodInterface.onBindViewHolder(viewHolder,i);
            }
        }
        @Override
        public long getItemId(int position) {
            if(recyclerMethodInterface!=null){
                return recyclerMethodInterface.getItemId(position);
            }else{
                return super.getItemId(position);
            }
        }
        @Override
        public int getItemCount() {
            if(recyclerMethodInterface!=null){
                return recyclerMethodInterface.getItemCount();
            }else{
                return 0;
            }
        }
    }
    public interface RecyclerMethodInterface{
        void onBindViewHolder(@NonNull ViewHolder viewHolder, int i);
        long getItemId(int position);
        int getItemCount();
    }
}

eg：

RecyclerWidget recyclerWidget=findViewById(R.id.widget_recycler);
recyclerWidget.initRecycler(context,R.layout.dialog_page_item);
adapter=recyclerWidget.setRecyclerAdapter(new RecyclerWidget.RecyclerMethodInterface() {
    @Override
    public void onBindViewHolder(@NonNull RecyclerView.ViewHolder viewHolder, int i) {}
    @Override
    public long getItemId(int position) {
        return position;
    }
    @Override
    public int getItemCount() {
        return 0;
    }
});

通用框架

从以下文章获取思路：
为RecyclerView打造通用Adapter 让RecyclerView更加好用

创建通用Holder

由于在Holder中需要获取未知数量与类型的控件，所以可通过View型集合来存储

在Holder构造方法中获取Context，Item布局赋值和创建View集合对象
定义一个静态方法创建Holder对象，并传入Context，Item布局
定义一个方法根据id获取控件，并将其以id为索引添加到view集合中，以供下次直接获取

创建通用Adapter，包括单布局，多布局和分类布局三种

单布局

构造方法获取Context，布局id和数据内容
定义一个抽象方法(该方法提供给客户端重写)
在onCreateViewHolder中调用静态方法创建Holder
在onBindViewHolder中调用抽象方法

多布局

需要多创建一个接口，里面定义根据type获取布局和根据数据和位置返回type两个接口方法

在重写方法getItemViewType中调用获取type的接口方法
在重写方法onCreateViewHolder中调用根据type获取布局的接口方法
调用静态方法传入相应布局创建Holder

坑

notifyDataSetChange不起作用

数据对象更新前和更新后必须是同一个对象，否则notifyDataSetChange将无效

因为其绑定的是第一个数据对象，更新数据时重新创建了一个数据对象，但原来那个数据对象并未改变，所以notifyDataSetChange后不会产生改变

控件，即RecyclerView也必须是同一个对象

只显示一条Item

若使用new LinearLayoutManager(this)Item布局高度不能使用match_parent

因为如果高度使用match_parent，一条Item便会占据整个屏幕，导致只显示一条Item

无法操作Item中的控件

public static GeneralHolder getHolder(Context context, ViewGroup parent, int layoutId){
    View itemView=LayoutInflater.from(context).inflate(layoutId,null);
    return new GeneralHolder(itemView,context);
}

想要操作Item中的控件，就必须为itemView提供parent布局

无法通过以上代码中的itemView操作Item中的控件，因为没有提供parent布局，需要更改为：

1	View itemView=LayoutInflater.from(context).inflate(layoutId,parent,false);