提到RecyclerView大家總會拿它與ListView相比較, RecyclerView是具有比ListView更具擴充套件性的控制元件, RecyclerView繼承的是ViewGroup, 可以說也是ViewGroup的官方定義控制元件, RecyclerView顧名思義其專注於Recycler複用, 它不再管理佈局, RecyclerView的佈局由LayoutManager來管理了, Adapter的使用也不再像ListView那樣繼承BaseAdapter, 而是繼承其內部類的RecyclerView.Adapter, 它是一個泛型類, 通常我們喜歡把它的泛型設定為RecyclerView.ViewHolder, RecyclerView.ViewHolde顯然也是一個RecyclerView的內部類, 可見RecyclerView已經把Adapter和ViewHolder完全封裝成自己的內部類, 其高度的Recycler思想可想而知.

RecyclerView的使用通常會涉及到一下幾個方法:

// 1.配置效率
mRecyclerView.setHasFixedSize(true);

// 2.配置佈局
mRecyclerView.setLayoutManager(new  LinearLayoutManager(this));

// 3.配置Adapter
mCustomAdapter = new CustomAdapter(this, mDatas);
mRecyclerView.setAdapter(mCustomAdapter);

發現並沒有像ListView那樣直接設定條目點選監聽的方法, 如何實現RecyclerView的條目點選監聽呢?這裡採用介面回撥的方式實現;

先看RecyclerView的Adapter程式碼

package com.suosuoshu.recyclerview;

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

import java.util.List;

// 自定義CustomAdapter 繼承RecyclerView.Adapter
 

public class CustomAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {

    private Context mContext;
    private List<Student> mDatas;

    // 採用介面回撥的方式實現RecyclerView的ItemClick
    public OnRecyclerViewListener mOnRecyclerViewListener;


    // 介面回撥第一步: 定義介面和介面中的方法
    interface OnRecyclerViewListener {

        void onItemClick(int position);

        boolean onItemLongClick(int position);
    }

    // 介面回撥第二步: 初始化介面的引用
    public void setOnRecyclerViewListener(OnRecyclerViewListener l) {
        this.mOnRecyclerViewListener = l;
    }

    public CustomAdapter(Context context, List<Student> datas) {
        mContext = context;
        mDatas = datas;
    }

    // 自定義ViewHolder
    public class CustomViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener, View.OnLongClickListener {

        public final TextView mTextName;
        public final TextView mTextAge;
        // 注意這裡的position與CustomViewHolder是對應的關係, 每個CustomViewHolder都有mTextName和mTextAge, 還有它的mPosition
        public int mPosition;

        public CustomViewHolder(View itemView) {
            super(itemView);
            mTextName = (TextView) itemView.findViewById(R.id.name);
            mTextAge = (TextView) itemView.findViewById(R.id.age);
            // 巧妙的呼叫了View的點選方法
            itemView.setOnClickListener(this);
            itemView.setOnLongClickListener(this);
        }

        // 介面回撥第三步, 實現onClick, 方法中是呼叫了介面的onItemClick抽象方法, 所以這裡之後肯定會被回調回來
        @Override
        public void onClick(View v) {
            if (mOnRecyclerViewListener != null) {
mOnRecyclerViewListener.onItemClick(mPosition);
            }
        }

        @Override
        public boolean onLongClick(View v) {
            if (mOnRecyclerViewListener != null) {
                return mOnRecyclerViewListener.onItemLongClick(mPosition);
            }
            return false;
        }
    }

// RecyclerView.Adapter的三個抽象方法實現
    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {

        View view = LayoutInflater.from(mContext).inflate(R.layout.itme_layout, null);
        CustomViewHolder customViewHolder = new CustomViewHolder(view);
        return customViewHolder;
    }

    @Override
    public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
        CustomViewHolder customViewHolder = (CustomViewHolder) holder;
        customViewHolder.mTextName.setText(mDatas.get(position).name);
        customViewHolder.mTextAge.setText(mDatas.get(position).age);
        customViewHolder.mPosition = position;
    }

    @Override
    public int getItemCount() {
        return mDatas != null ? mDatas.size() : 0;
    }
}

這是MainActivity 中的程式碼

package com.suosuoshu.recyclerview;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.widget.Toast;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity implements CustomAdapter.OnRecyclerViewListener {

    private RecyclerView mRecyclerView;
    private List<Student> mDatas;
    private CustomAdapter mCustomAdapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        initView();
        initData();
    }
    // 初始化控制元件
    private void initView() {
        mRecyclerView = (RecyclerView) findViewById(R.id.recyclerview);
    }
    // 初始化資料
    private void initData() {
    // 這裡是模擬資料
        mDatas = new ArrayList<>();

        for (int i = 0; i < 100; i++) {
            Student student = new Student("明明", "18");
            mDatas.add(student);
        }

        // 1.配置效率
        mRecyclerView.setHasFixedSize(true);

        // 2.配置佈局
        mRecyclerView.setLayoutManager(new LinearLayoutManager(this));

        // 3.配置Adapter
        mCustomAdapter = new CustomAdapter(this, mDatas);
        mRecyclerView.setAdapter(mCustomAdapter);

        // 4.注意, 是讓Adapter去設定點選監聽事件,setOnRecyclerViewListener方法是在CustomAdapter中定義的
        mCustomAdapter.setOnRecyclerViewListener(this);
    }

// 介面回撥第四步, 這是才是最終被呼叫的方法
    @Override
    public void onItemClick(int position) {
        Toast.makeText(MainActivity.this, "點選了第" + position + "個條目", Toast.LENGTH_SHORT).show();
    }

    @Override
    public boolean onItemLongClick(int position) {
        return false;
    }
}

一個簡單的Bean類模擬資料

package com.suosuoshu.recyclerview;
public class Student {
    public String name;
    public String age;

    public Student(String name, String age) {
        this.name = name;
        this.age = age;
    }
}