Android学习笔记：RecyclerView_怎么看recyclerview-v7库与com.android.support:appcompat库

示例代码地址：
（1）基本用法：https://github.com/ambition-hb/RecyclerViewDemo
（2）横向滚动：https://github.com/ambition-hb/RecyclerViewDemo/tree/one
（3）瀑布流布局：https://github.com/ambition-hb/RecyclerViewDemo/tree/two
（4）点击事件：https://github.com/ambition-hb/RecyclerViewDemo/tree/three

上一节介绍了ListView，虽然其很强大，但是有一定的缺点。如果不使用一定的方法提升它的运行效率，ListView的性能将会非常差。此外，它的扩展性能也不好，因为LListView只能纵向滚动。

从Android 5.0开始，谷歌公司推出了一个用于大量数据展示的新控件RecylerView，可以用来代替传统的ListView，更加强大和灵活。不仅可以轻松实现和ListView同样的效果，还优化了ListView中存在的各种不足之处。

RecyclerView架构提供了一种插拔式体验，它具有高度的解耦、异常的灵活性和更高的效率，通过设置它提供的不同LayoutManager、ItemDecoration、ItemAnimator可实现更加丰富多彩的效果。但是RecyclerView也有一定的缺点：①设置列表的分割线时需要自定义（默认没有分隔线）；②列表的点击事件需要自己手动实现；

---

一、RecyclerView相关的类

（1）Adapter最大的改进就是对ViewHolder进行了封装定义，我们只需要自定义一个ViewHolder继承RecyclerView.ViewHolder就可以了。此外，Adapter继承了RecyclerView.Adapter，在onCreateViewHolder()方法中加载条目布局，在onBindViewHolder()方法中将视图与数据进行绑定。

（2）设置分隔线：谷歌没有提供默认的分隔线，需要我们继承RecyclerView.ItemDecoration来自定义分隔线。只需在调用setAdapter()方法之前使用mRecyclerView.addItemDecoration() 方法来加入分隔线。

（3）使用Adapter的时候，如果采用ViewHolder做缓存，在getView()方法中无论这项convertView的每个子控件是否需要设置属性（比如某个TextView设置的文本可能为null，某个按钮的背景色为透明，某控件的颜色为透明等），都需要为其显式设置属性（TextView的文本为空也需要设置setText("")，背景透明也需要设置），否则在滑动的过程中，因为adapter item复用的原因，会出现内容的显式错乱。

---

二、基本用法

在app/build.gradle文件的dependencies闭包中添加如下内容：

compile 'com.android.support:recyclerview-v7:26.0.0-alpha1'
1

需要注意的是，RecyclerView版本需要与appcompat版本匹配，比如appcompat版本为26.+，那么RecyclerView版本也应为26.+，如下所示：

compile 'com.android.support:appcompat-v7:26.+'
compile 'com.android.support:recyclerview-v7:26.0.0-alpha1'
1
2

添加完成后点击同步，随后修改activity_main/xml布局文件，由于RecyclerView不是内置在系统SDK中的，需要将完整的包路径写出来，如下所示：

<?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="match_parent">

    <android.support.v7.widget.RecyclerView
        android:id="@+id/recycler_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>

</LinearLayout>
1
2
3
4
5
6
7
8
9
10
11

新建Weather类和其对应的布局文件weather_item.xml，如下所示：

package com.haobi.recyclerviewdemo;

public class Weather {
    private String name;
    private int imageId;

    public Weather(String name, int imageId) {
        this.name = name;
        this.imageId = imageId;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getImageId() {
        return imageId;
    }

    public void setImageId(int imageId) {
        this.imageId = imageId;
    }
}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27

<?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">

    <ImageView
        android:id="@+id/weather_image"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/i_999_unknown"/>

    <TextView
        android:id="@+id/weather_name"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:layout_marginLeft="10dp"
        android:text="未知天气"/>

</LinearLayout>
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21

接下来为RecyclerView提供一个适配器，新建WeatherAdapter类，让这个适配器继承自RecyclerView.Adapter，并将泛型指定为FruitAdapter.ViewHolder（WeatherAdapter中的一个内部类），代码如下：

package com.haobi.recyclerviewdemo;

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

import java.util.List;

/**
 * Created by 15739 on 2019/8/2.
 */

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

    private List<Weather> mWeatherList;

    //静态内部类：可以不依赖于外部类实例化而被实例化
    static class ViewHolder extends RecyclerView.ViewHolder{
        ImageView weatherImage;
        TextView weatherName;
        //静态内部类的构造函数
        public ViewHolder(View view){
            //传入的view就是RecyclerView子项的最外层布局
            super(view);
            //根据布局获取布局实例
            weatherImage = (ImageView) view.findViewById(R.id.weather_image);
            weatherName = (TextView) view.findViewById(R.id.weather_name);
        }
    }

    //构造函数
    public WeatherAdapter(List<Weather> weatherList){
        //把要展示的数据源传递进来，并赋给一个全局变量mWeatherList
        mWeatherList = weatherList;
    }

    //创建ViewHolder实例
    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        //加载weather_item布局
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.weather_item, parent, false);
        //创建ViewHolder实例，并将布局传入ViewHolder构造函数
        ViewHolder holder = new ViewHolder(view);
        //将ViewHolder实例返回
        return holder;
    }

    //对RecyclerView子项的数据进行赋值，会在每个子项滚动到屏幕内时执行
    @Override
    public void onBindViewHolder(WeatherAdapter.ViewHolder holder, int position) {
        //通过position参数得到当前Weather实例
        Weather weather = mWeatherList.get(position);
        //将数据设置到ViewHolder的ImageView和TextView中
        holder.weatherImage.setImageResource(weather.getImageId());
        holder.weatherName.setText(weather.getName());
    }

    //返回数据源长度
    @Override
    public int getItemCount() {
        //返回RecyclerView一共有多少个子项
        return mWeatherList.size();
    }
}

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68

在上述代码中，首先定义了一个内部类ViewHolder，使其继承自RecyclerView.ViewHolder，并在其内部添加构造函数。然后在WeatherAdapter类中添加一个构造函数，将要展示的数据源传递进来，并赋给一个全局变量mWeatherList。由于WeatherAdapter是继承自RecyclerView.Adapter的，那么必须重写onCreateViewHolder()、onBindViewHolder()、getItemCount()三个方法。

最后，修改MainActivity中的代码，如下所示：

package com.haobi.recyclerviewdemo;

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

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

public class MainActivity extends AppCompatActivity {

    private List<Weather> weatherList = new ArrayList<>();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initWeather();//初始化天气数据
        //获取RecyclerView实例
        RecyclerView recyclerView = (RecyclerView)findViewById(R.id.recycler_view);
        //创建LinearLayoutManager对象
        LinearLayoutManager layoutManager = new LinearLayoutManager(this);
        //将LinearLayoutManager对象设置到RecyclerView当中
        recyclerView.setLayoutManager(layoutManager);
        //创建WeatherAdapter实例并将天气数据传入WeatherAdapter的构造函数中
        WeatherAdapter adapter = new WeatherAdapter(weatherList);
        //调用RecyclerView的setAdapter()方法来设置适配器
        recyclerView.setAdapter(adapter);
    }

    private void initWeather(){
        Weather i_100 = new Weather("Sunny", R.drawable.i_100_sunny);
        weatherList.add(i_100);
        Weather i_101 = new Weather("Cloudy", R.drawable.i_101_cloudy);
        weatherList.add(i_101);
        Weather i_102 = new Weather("Few Clouds", R.drawable.i_102_few_clouds);
        weatherList.add(i_102);
        Weather i_103 = new Weather("Partly Cloudy", R.drawable.i_103_partly_cloudy);
        weatherList.add(i_103);
        Weather i_104 = new Weather("Overcast", R.drawable.i_104_overcast);
        weatherList.add(i_104);
        Weather i_200 = new Weather("Windy", R.drawable.i_200_windy);
        weatherList.add(i_200);
        Weather i_201 = new Weather("Calm", R.drawable.i_201_calm);
        weatherList.add(i_201);
        Weather i_202 = new Weather("Light Breeze", R.drawable.i_202_light_breeze);
        weatherList.add(i_202);
        Weather i_203 = new Weather("Moderate", R.drawable.i_203_moderate);
        weatherList.add(i_203);
        Weather i_204 = new Weather("Fresh Breeze", R.drawable.i_204_fresh_breeze);
        weatherList.add(i_204);
        Weather i_205 = new Weather("Strong Breeze", R.drawable.i_205_strong_breeze);
        weatherList.add(i_205);
        Weather i_206 = new Weather("High Wind", R.drawable.i_206_high_wind);
        weatherList.add(i_206);
        Weather i_207 = new Weather("Gale", R.drawable.i_207_gale);
        weatherList.add(i_207);
        Weather i_208 = new Weather("Strong Gale", R.drawable.i_208_strong_gale);
        weatherList.add(i_208);
        Weather i_209 = new Weather("Storm", R.drawable.i_209_storm);
        weatherList.add(i_209);
        Weather i_210 = new Weather("Violent Storm", R.drawable.i_210_violent_storm);
        weatherList.add(i_210);
        Weather i_211 = new Weather("Hurricane", R.drawable.i_211_hurricane);
        weatherList.add(i_211);
        Weather i_212 = new Weather("Tornado", R.drawable.i_212_tornado);
        weatherList.add(i_212);
        Weather i_213 = new Weather("Tropical Storm", R.drawable.i_213_tropical_storm);
        weatherList.add(i_213);
        Weather i_300 = new Weather("Shower Rain", R.drawable.i_300_shower_rain);
        weatherList.add(i_300);
        Weather i_301 = new Weather("Heavy Shower Rain", R.drawable.i_301_heavy_shower_rain);
        weatherList.add(i_301);
        Weather i_302 = new Weather("Thundershower", R.drawable.i_302_thundershower);
        weatherList.add(i_302);
        Weather i_303 = new Weather("Heavy Thunderstorm", R.drawable.i_303_heavy_thunderstorm);
        weatherList.add(i_303);
        Weather i_304 = new Weather("Thundershower with hail", R.drawable.i_304_thundershower_with_hail);
        weatherList.add(i_304);
        Weather i_305 = new Weather("Light Rain", R.drawable.i_305_light_rain);
        weatherList.add(i_305);
        Weather i_306 = new Weather("Moderate Rain", R.drawable.i_306_moderate_rain);
        weatherList.add(i_306);
        Weather i_307 = new Weather("Heavy Rain", R.drawable.i_307_heavy_rain);
        weatherList.add(i_307);
        Weather i_308 = new Weather("Extreme Rain", R.drawable.i_308_extreme_rain);
        weatherList.add(i_308);
        Weather i_309 = new Weather("Drizzle Rain", R.drawable.i_309_drizzle_rain);
        weatherList.add(i_309);
        Weather i_310 = new Weather("Storm", R.drawable.i_310_storm);
        weatherList.add(i_310);
        Weather i_311 = new Weather("Heavy Storm", R.drawable.i_311_heavy_storm);
        weatherList.add(i_311);
        Weather i_312 = new Weather("Severe Storm", R.drawable.i_312_severe_storm);
        weatherList.add(i_312);
        Weather i_313 = new Weather("Freezing Rain", R.drawable.i_313_freezing_rain);
        weatherList.add(i_313);
        Weather i_314 = new Weather("Light to moderate rain", R.drawable.i_314_light_to_moderate_rain);
        weatherList.add(i_314);
        Weather i_315 = new Weather("Moderate to heavy rain", R.drawable.i_315_moderate_to_heavy_rain);
        weatherList.add(i_315);
        Weather i_316 = new Weather("Heavy rain to storm", R.drawable.i_316_heavy_rain_to_storm);
        weatherList.add(i_316);
        Weather i_317 = new Weather("Storm to heavy storm", R.drawable.i_317_storm_to_heavy_storm);
        weatherList.add(i_317);
        Weather i_318 = new Weather("Heavy to severe storm", R.drawable.i_318_heavy_to_server_storm);
        weatherList.add(i_318);
        Weather i_399 = new Weather("Rain", R.drawable.i_399_rain);
        weatherList.add(i_399);
        Weather i_400 = new Weather("Light Snow", R.drawable.i_400_light_snow);
        weatherList.add(i_400);
        Weather i_401 = new Weather("Moderate Snow", R.drawable.i_401_moderate_snow);
        weatherList.add(i_401);
        Weather i_402 = new Weather("Heavy Snow", R.drawable.i_402_heavy_snow);
        weatherList.add(i_402);
        Weather i_403 = new Weather("Snowstorm", R.drawable.i_403_snowstorm);
        weatherList.add(i_403);
        Weather i_404 = new Weather("Sleet", R.drawable.i_404_sleet);
        weatherList.add(i_404);
        Weather i_405 = new Weather("Rain And Snow", R.drawable.i_405_rain_and_snow);
        weatherList.add(i_405);
        Weather i_406 = new Weather("Shower Snow", R.drawable.i_406_shower_snow);
        weatherList.add(i_406);
        Weather i_407 = new Weather("Snow Flurry", R.drawable.i_407_snow_flurry);
        weatherList.add(i_407);
        Weather i_408 = new Weather("Light to moderate snow", R.drawable.i_408_light_to_moderate_snow);
        weatherList.add(i_408);
        Weather i_409 = new Weather("Moderate to heavy snow", R.drawable.i_409_moderate_to_heavy_snow);
        weatherList.add(i_409);
        Weather i_410 = new Weather("Heavy snow to snowstorm", R.drawable.i_410_heavy_snow_to_snowstorm);
        weatherList.add(i_410);
        Weather i_499 = new Weather("Snow", R.drawable.i_499_snow);
        weatherList.add(i_499);
        Weather i_500 = new Weather("Mist", R.drawable.i_500_mist);
        weatherList.add(i_500);
        Weather i_501 = new Weather("Foggy", R.drawable.i_501_foggy);
        weatherList.add(i_501);
        Weather i_502 = new Weather("Haze", R.drawable.i_502_haze);
        weatherList.add(i_502);
        Weather i_503 = new Weather("Sand", R.drawable.i_503_sand);
        weatherList.add(i_503);
        Weather i_504 = new Weather("Dust", R.drawable.i_504_dust);
        weatherList.add(i_504);
        Weather i_507 = new Weather("Duststorm", R.drawable.i_507_duststorm);
        weatherList.add(i_507);
        Weather i_508 = new Weather("Sandstorm", R.drawable.i_508_sandstorm);
        weatherList.add(i_508);
        Weather i_509 = new Weather("Dense fog", R.drawable.i_509_dense_fog);
        weatherList.add(i_509);
        Weather i_510 = new Weather("Strong fog", R.drawable.i_510_strong_fog);
        weatherList.add(i_510);
        Weather i_511 = new Weather("Moderate haze", R.drawable.i_511_moderate_haze);
        weatherList.add(i_511);
        Weather i_512 = new Weather("Heavy haze", R.drawable.i_512_heavy_haze);
        weatherList.add(i_512);
        Weather i_513 = new Weather("Severe haze", R.drawable.i_513_severe_haze);
        weatherList.add(i_513);
        Weather i_514 = new Weather("Heavy fog", R.drawable.i_514_heavy_fog);
        weatherList.add(i_514);
        Weather i_515 = new Weather("Extra heavy fog", R.drawable.i_515_extra_heavy_fog);
        weatherList.add(i_515);
        Weather i_900 = new Weather("Hot", R.drawable.i_900_hot);
        weatherList.add(i_900);
        Weather i_901 = new Weather("Cold", R.drawable.i_901_cold);
        weatherList.add(i_901);
        Weather i_999 = new Weather("Unknown", R.drawable.i_999_unknown);
        weatherList.add(i_999);
    }
}

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171

至此，RecyclerView实现类与ListView一模一样的效果，效果如下图所示：

---

三、横向滚动

RecyclerView除了能够实现ListView的纵向滚动效果，还可以实现横向滚动效果。
首先，修改weather_item.xml布局文件，将其中的元素改为垂直排列，并将宽度指定为固定值，代码如下所示：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="100dp"
    android:layout_height="wrap_content">

    <ImageView
        android:id="@+id/weather_image"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/i_999_unknown"
        android:layout_gravity="center_horizontal"/>

    <TextView
        android:id="@+id/weather_name"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:text="未知天气"
        android:layout_marginTop="10dp"/>

</LinearLayout>
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23

接下来，修改MainActivity中的代码，只需要添加一行代码，调用LinearLayoutManager的setOrientation()方法来设置布局的排列方向，如下所示：

@Override
protected void onCreate(Bundle savedInstanceState) {
    ......
    //创建LinearLayoutManager对象
    LinearLayoutManager layoutManager = new LinearLayoutManager(this);
    //调用LinearLayoutManager的setOrientation()方法来设置布局的排列方向
    //默认是纵向排列
    layoutManager.setOrientation(LinearLayoutManager.HORIZONTAL);
    //将LinearLayoutManager对象设置到RecyclerView当中
    recyclerView.setLayoutManager(layoutManager);
    ......
}
1
2
3
4
5
6
7
8
9
10
11
12

效果图如下所示：

---

四、瀑布流布局

除了LinearLayoutManager之外，RecyclerView还提供了GridLayoutManager和StaggeredGridLayoutManager这两种内置的布局排列方式。GridLayoutManager可以实现网格布局，StaggeredGridLayoutManager可以实现瀑布流布局。
首先，修改weather_item.xml布局文件。如下所示：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_margin="5dp">

    <ImageView
        android:id="@+id/weather_image"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/i_999_unknown"
        android:layout_gravity="center_horizontal"/>

    <TextView
        android:id="@+id/weather_name"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="left"
        android:text="未知天气"
        android:layout_marginTop="10dp"/>

</LinearLayout>
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24

然后，修改MainActivity，创建一个StaggeredGridLayoutManager实例，接收两个参数，第一个参数用于指定布局的列数，传入3即表示会把布局分为三列；第二个参数用于指定布局的排列方向，传入StaggeredGridLayoutManager.VERTICAL表示会让布局纵向排列。代码如下所示：

package com.haobi.recyclerviewdemo;

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

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

public class MainActivity extends AppCompatActivity {

    private List<Weather> weatherList = new ArrayList<>();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initWeather();//初始化天气数据
        //获取RecyclerView实例
        RecyclerView recyclerView = (RecyclerView)findViewById(R.id.recycler_view);
        //创建StaggeredGridLayoutManager实例
        StaggeredGridLayoutManager layoutManager = new StaggeredGridLayoutManager(3, StaggeredGridLayoutManager.VERTICAL);
        //将LinearLayoutManager对象设置到RecyclerView当中
        recyclerView.setLayoutManager(layoutManager);
        //创建WeatherAdapter实例并将天气数据传入WeatherAdapter的构造函数中
        WeatherAdapter adapter = new WeatherAdapter(weatherList);
        //调用RecyclerView的setAdapter()方法来设置适配器
        recyclerView.setAdapter(adapter);
    }

    private void initWeather(){
        Weather i_100 = new Weather("Sunny", R.drawable.i_100_sunny);
        weatherList.add(i_100);
        Weather i_101 = new Weather("Cloudy", R.drawable.i_101_cloudy);
        weatherList.add(i_101);
        Weather i_102 = new Weather("Few Clouds", R.drawable.i_102_few_clouds);
        weatherList.add(i_102);
        Weather i_103 = new Weather("Partly Cloudy", R.drawable.i_103_partly_cloudy);
        weatherList.add(i_103);
        Weather i_104 = new Weather("Overcast", R.drawable.i_104_overcast);
        weatherList.add(i_104);
        Weather i_200 = new Weather("Windy", R.drawable.i_200_windy);
        weatherList.add(i_200);
        Weather i_201 = new Weather("Calm", R.drawable.i_201_calm);
        weatherList.add(i_201);
        Weather i_202 = new Weather("Light Breeze", R.drawable.i_202_light_breeze);
        weatherList.add(i_202);
        Weather i_203 = new Weather("Moderate", R.drawable.i_203_moderate);
        weatherList.add(i_203);
        Weather i_204 = new Weather("Fresh Breeze", R.drawable.i_204_fresh_breeze);
        weatherList.add(i_204);
        Weather i_205 = new Weather("Strong Breeze", R.drawable.i_205_strong_breeze);
        weatherList.add(i_205);
        Weather i_206 = new Weather("High Wind", R.drawable.i_206_high_wind);
        weatherList.add(i_206);
        Weather i_207 = new Weather("Gale", R.drawable.i_207_gale);
        weatherList.add(i_207);
        Weather i_208 = new Weather("Strong Gale", R.drawable.i_208_strong_gale);
        weatherList.add(i_208);
        Weather i_209 = new Weather("Storm", R.drawable.i_209_storm);
        weatherList.add(i_209);
        Weather i_210 = new Weather("Violent Storm", R.drawable.i_210_violent_storm);
        weatherList.add(i_210);
        Weather i_211 = new Weather("Hurricane", R.drawable.i_211_hurricane);
        weatherList.add(i_211);
        Weather i_212 = new Weather("Tornado", R.drawable.i_212_tornado);
        weatherList.add(i_212);
        Weather i_213 = new Weather("Tropical Storm", R.drawable.i_213_tropical_storm);
        weatherList.add(i_213);
        Weather i_300 = new Weather("Shower Rain", R.drawable.i_300_shower_rain);
        weatherList.add(i_300);
        Weather i_301 = new Weather("Heavy Shower Rain", R.drawable.i_301_heavy_shower_rain);
        weatherList.add(i_301);
        Weather i_302 = new Weather("Thundershower", R.drawable.i_302_thundershower);
        weatherList.add(i_302);
        Weather i_303 = new Weather("Heavy Thunderstorm", R.drawable.i_303_heavy_thunderstorm);
        weatherList.add(i_303);
        Weather i_304 = new Weather("Thundershower with hail", R.drawable.i_304_thundershower_with_hail);
        weatherList.add(i_304);
        Weather i_305 = new Weather("Light Rain", R.drawable.i_305_light_rain);
        weatherList.add(i_305);
        Weather i_306 = new Weather("Moderate Rain", R.drawable.i_306_moderate_rain);
        weatherList.add(i_306);
        Weather i_307 = new Weather("Heavy Rain", R.drawable.i_307_heavy_rain);
        weatherList.add(i_307);
        Weather i_308 = new Weather("Extreme Rain", R.drawable.i_308_extreme_rain);
        weatherList.add(i_308);
        Weather i_309 = new Weather("Drizzle Rain", R.drawable.i_309_drizzle_rain);
        weatherList.add(i_309);
        Weather i_310 = new Weather("Storm", R.drawable.i_310_storm);
        weatherList.add(i_310);
        Weather i_311 = new Weather("Heavy Storm", R.drawable.i_311_heavy_storm);
        weatherList.add(i_311);
        Weather i_312 = new Weather("Severe Storm", R.drawable.i_312_severe_storm);
        weatherList.add(i_312);
        Weather i_313 = new Weather("Freezing Rain", R.drawable.i_313_freezing_rain);
        weatherList.add(i_313);
        Weather i_314 = new Weather("Light to moderate rain", R.drawable.i_314_light_to_moderate_rain);
        weatherList.add(i_314);
        Weather i_315 = new Weather("Moderate to heavy rain", R.drawable.i_315_moderate_to_heavy_rain);
        weatherList.add(i_315);
        Weather i_316 = new Weather("Heavy rain to storm", R.drawable.i_316_heavy_rain_to_storm);
        weatherList.add(i_316);
        Weather i_317 = new Weather("Storm to heavy storm", R.drawable.i_317_storm_to_heavy_storm);
        weatherList.add(i_317);
        Weather i_318 = new Weather("Heavy to severe storm", R.drawable.i_318_heavy_to_server_storm);
        weatherList.add(i_318);
        Weather i_399 = new Weather("Rain", R.drawable.i_399_rain);
        weatherList.add(i_399);
        Weather i_400 = new Weather("Light Snow", R.drawable.i_400_light_snow);
        weatherList.add(i_400);
        Weather i_401 = new Weather("Moderate Snow", R.drawable.i_401_moderate_snow);
        weatherList.add(i_401);
        Weather i_402 = new Weather("Heavy Snow", R.drawable.i_402_heavy_snow);
        weatherList.add(i_402);
        Weather i_403 = new Weather("Snowstorm", R.drawable.i_403_snowstorm);
        weatherList.add(i_403);
        Weather i_404 = new Weather("Sleet", R.drawable.i_404_sleet);
        weatherList.add(i_404);
        Weather i_405 = new Weather("Rain And Snow", R.drawable.i_405_rain_and_snow);
        weatherList.add(i_405);
        Weather i_406 = new Weather("Shower Snow", R.drawable.i_406_shower_snow);
        weatherList.add(i_406);
        Weather i_407 = new Weather("Snow Flurry", R.drawable.i_407_snow_flurry);
        weatherList.add(i_407);
        Weather i_408 = new Weather("Light to moderate snow", R.drawable.i_408_light_to_moderate_snow);
        weatherList.add(i_408);
        Weather i_409 = new Weather("Moderate to heavy snow", R.drawable.i_409_moderate_to_heavy_snow);
        weatherList.add(i_409);
        Weather i_410 = new Weather("Heavy snow to snowstorm", R.drawable.i_410_heavy_snow_to_snowstorm);
        weatherList.add(i_410);
        Weather i_499 = new Weather("Snow", R.drawable.i_499_snow);
        weatherList.add(i_499);
        Weather i_500 = new Weather("Mist", R.drawable.i_500_mist);
        weatherList.add(i_500);
        Weather i_501 = new Weather("Foggy", R.drawable.i_501_foggy);
        weatherList.add(i_501);
        Weather i_502 = new Weather("Haze", R.drawable.i_502_haze);
        weatherList.add(i_502);
        Weather i_503 = new Weather("Sand", R.drawable.i_503_sand);
        weatherList.add(i_503);
        Weather i_504 = new Weather("Dust", R.drawable.i_504_dust);
        weatherList.add(i_504);
        Weather i_507 = new Weather("Duststorm", R.drawable.i_507_duststorm);
        weatherList.add(i_507);
        Weather i_508 = new Weather("Sandstorm", R.drawable.i_508_sandstorm);
        weatherList.add(i_508);
        Weather i_509 = new Weather("Dense fog", R.drawable.i_509_dense_fog);
        weatherList.add(i_509);
        Weather i_510 = new Weather("Strong fog", R.drawable.i_510_strong_fog);
        weatherList.add(i_510);
        Weather i_511 = new Weather("Moderate haze", R.drawable.i_511_moderate_haze);
        weatherList.add(i_511);
        Weather i_512 = new Weather("Heavy haze", R.drawable.i_512_heavy_haze);
        weatherList.add(i_512);
        Weather i_513 = new Weather("Severe haze", R.drawable.i_513_severe_haze);
        weatherList.add(i_513);
        Weather i_514 = new Weather("Heavy fog", R.drawable.i_514_heavy_fog);
        weatherList.add(i_514);
        Weather i_515 = new Weather("Extra heavy fog", R.drawable.i_515_extra_heavy_fog);
        weatherList.add(i_515);
        Weather i_900 = new Weather("Hot", R.drawable.i_900_hot);
        weatherList.add(i_900);
        Weather i_901 = new Weather("Cold", R.drawable.i_901_cold);
        weatherList.add(i_901);
        Weather i_999 = new Weather("Unknown", R.drawable.i_999_unknown);
        weatherList.add(i_999);
    }
}

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172

效果图如下图所示：

---

五、点击事件

RecyclerView可以轻松实现子项中任意控件或布局的点击事件，RecyclerView需要针对具体的子项View去注册点击事件，修改WeatherAdapter中的代码，如下图所示：

package com.haobi.recyclerviewdemo;

import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;

import java.util.List;

/**
 * Created by 15739 on 2019/8/2.
 */

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

    private List<Weather> mWeatherList;

    //静态内部类：可以不依赖于外部类实例化而被实例化
    static class ViewHolder extends RecyclerView.ViewHolder{

        //添加weatherView变量来保存子项最外层布局（图片+文字区域）的实例
        View weatherView;

        ImageView weatherImage;
        TextView weatherName;
        //静态内部类的构造函数
        public ViewHolder(View view){
            //传入的view就是RecyclerView子项的最外层布局
            super(view);
            //根据布局获取布局实例
            weatherView = view;//图片加文字区域
            weatherImage = (ImageView) view.findViewById(R.id.weather_image);
            weatherName = (TextView) view.findViewById(R.id.weather_name);
        }
    }

    //构造函数
    public WeatherAdapter(List<Weather> weatherList){
        //把要展示的数据源传递进来，并赋给一个全局变量mWeatherList
        mWeatherList = weatherList;
    }

    //创建ViewHolder实例
    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        //加载weather_item布局
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.weather_item, parent, false);
        //创建ViewHolder实例，并将布局传入ViewHolder构造函数
        final ViewHolder holder = new ViewHolder(view);
        holder.weatherView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //获取position
                int position = holder.getAdapterPosition();
                //通过position获取实例
                Weather weather = mWeatherList.get(position);
                Toast.makeText(v.getContext(), "View:"+weather.getName(), Toast.LENGTH_SHORT).show();
            }
        });
        holder.weatherImage.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //获取position
                int position = holder.getAdapterPosition();
                //通过position获取实例
                Weather weather = mWeatherList.get(position);
                Toast.makeText(v.getContext(), "Image:"+weather.getName(), Toast.LENGTH_SHORT).show();
            }
        });
        //将ViewHolder实例返回
        return holder;
    }

    //对RecyclerView子项的数据进行赋值，会在每个子项滚动到屏幕内时执行
    @Override
    public void onBindViewHolder(WeatherAdapter.ViewHolder holder, int position) {
        //通过position参数得到当前Weather实例
        Weather weather = mWeatherList.get(position);
        //将数据设置到ViewHolder的ImageView和TextView中
        holder.weatherImage.setImageResource(weather.getImageId());
        holder.weatherName.setText(weather.getName());
    }

    //返回数据源长度
    @Override
    public int getItemCount() {
        //返回RecyclerView一共有多少个子项
        return mWeatherList.size();
    }
}

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94

---