Android简单版天气预报，显示天气预报（第二步）

接着上一步的：[https://blog.csdn.net/weixin_44889138/article/details/102748057]
上一步的链接

ListView的改进，因为每次在getView()方法中还是会调用View的findViewById()方法来获取一次控件的实例，写一个内部类，利用**view.setTag()**存储，getTag()取。其实实现的机制跟RecycleView差不多

package com.example.xhhweather;import android.content.Intent;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.BaseAdapter;import android.widget.ImageView;import android.widget.TextView;import android.widget.Toast;import java.util.List;public class CityAdapter extends BaseAdapter {    //    class ViewHolder{        TextView TVcityName;        //删除城市        ImageView ivDelCity;        //选择城市后返回天气界面        ImageView ivQuyCity;    }    private List<CityItem> list;    public CityAdapter(List<CityItem> list){        this.list=list;    }    @Override    public View getView(final int position, View covertView, final ViewGroup viewGroup) {        View view;        ViewHolder viewHolder;        if(covertView==null){            view= LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.city_item,viewGroup,false);            viewHolder=new ViewHolder();            viewHolder.TVcityName=view.findViewById(R.id.tv_city_name);            viewHolder.ivQuyCity=view.findViewById(R.id.btn_move);            viewHolder.ivDelCity=view.findViewById(R.id.iv_del_city);            //将viewHolder存入在view中            view.setTag(viewHolder);        }else{            view=covertView;            viewHolder= (ViewHolder) view.getTag();        }        CityItem cityItem= list.get(position);        viewHolder.TVcityName.setText(cityItem.getCityName());        //删除城市        viewHolder.ivDelCity.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View view) {                list.remove(position);                notifyDataSetChanged();//本身就是adapter            }        });        //移动城市        viewHolder.ivQuyCity.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View view) {                CityItem city=list.get(position);                Toast.makeText(viewGroup.getContext(),city.getCityPinYin(),Toast.LENGTH_SHORT).show();            }        });        return view;    }    @Override    public int getCount() {        return list.size();    }    @Override    public Object getItem(int i) {        return list.get(i);    }    @Override    public long getItemId(int i) {        return i;    }}

package com.example.xhhweather;import androidx.annotation.Nullable;import androidx.appcompat.app.AppCompatActivity;import android.content.Intent;import android.os.Bundle;import android.util.Log;import android.view.View;import android.widget.Button;import android.widget.TextView;import android.widget.Toast;import com.bumptech.glide.Glide;import com.example.xhhweather.gson.Weather;import com.example.xhhweather.gson.WeatherResDaily;import com.example.xhhweather.gson.WeatherResults;import com.google.gson.Gson;import com.google.gson.reflect.TypeToken;import java.io.IOException;import java.util.ArrayList;import java.util.List;import okhttp3.Call;import okhttp3.Callback;import okhttp3.Response;public class MainActivity extends AppCompatActivity{    private Button btnSelectCity;    private TextView weatherTitleCityname;    private TextView tvFirstDayDate;    private TextView tvFirstDayPhe;    private TextView tvFirstDayHigh;    private TextView tvFirstDayLow;    private TextView tvSecondDayDate;    private TextView tvSecondDayPhe;    private TextView tvSecondDayHigh;    private TextView tvSecondDayLow;    private TextView tvThirdDayDate;    private TextView tvThirdDayPhe;    private TextView tvThirdDayHigh;    private TextView tvThirdDayLow;    private TextView temperatureText;    private TextView caseText;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        initfindViewById();        btnSelectCity.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View view) {                Intent intent=new Intent(MainActivity.this,SelectCity.class);                startActivityForResult(intent,1001);            }        });    }    /**     * 初始化     */    private void initfindViewById(){        btnSelectCity=findViewById(R.id.manage_city_btn);        weatherTitleCityname=findViewById(R.id.weather_title_cityname);        temperatureText=findViewById(R.id.temperature_text);        caseText=findViewById(R.id.case_text);        tvFirstDayDate=findViewById(R.id.tv_firstday_date);        tvFirstDayPhe=findViewById(R.id.tv_firstday_phe);        tvFirstDayHigh=findViewById(R.id.tv_firstday_high);        tvFirstDayLow=findViewById(R.id.tv_firstday_low);        tvSecondDayDate=findViewById(R.id.tv_secondday_date);        tvSecondDayPhe=findViewById(R.id.tv_secondday_phe);        tvSecondDayHigh=findViewById(R.id.tv_secondday_high);        tvSecondDayLow=findViewById(R.id.tv_secondday_low);        tvThirdDayDate=findViewById(R.id.tv_thirdday_date);        tvThirdDayPhe=findViewById(R.id.tv_thirdday_phe);        tvThirdDayHigh=findViewById(R.id.tv_thirdday_high);        tvThirdDayLow=findViewById(R.id.tv_thirdday_low);    }    /**     * 得到     * @param requestCode     * @param resultCode     * @param data     */    @Override    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {        super.onActivityResult(requestCode, resultCode, data);        if(requestCode==1001 && resultCode==1002){            String cityPinYin=data.getStringExtra("CITYPINYIN");            //Log.e("MainActivity","返回城市的拼音"+cityPinYin);            //心知天气的api            String url="https://api.seniverse.com/v3/weather/daily.json?key=SojsF4VNkV_cTQexq&location=" + cityPinYin + "&language=zh-Hans&unit=c&start=0&days=5";            HttpUtil.sendOkHttpRequest(url, new Callback() {                @Override                public void onFailure(Call call, IOException e) {                    e.printStackTrace();                }                @Override                public void onResponse(Call call, Response response) throws IOException {                    final String weatherData=response.body().string();                    runOnUiThread(new Runnable() {                        @Override                        public void run() {                            Log.e("MainActivity","得到的数据"+weatherData);                            Gson gson =new Gson();                            Weather weatherInfo=gson.fromJson(weatherData,Weather.class);                            WeatherResults results=weatherInfo.getResults().get(0);                            String cityName=results.getLocation().getName();//城市名称                            weatherTitleCityname.setText(cityName);                            //将3天内的天气数据获得后存入二维数组                            String [] [] resultDaily=new String[3][5];                            for(int i=0;i<3;i++){                                for(int j=0;j<4;){                                    resultDaily[i][j]=results.getDaily().get(i).getDate();j++;                                    resultDaily[i][j]=results.getDaily().get(i).getText_day();j++;                                    resultDaily[i][j]=results.getDaily().get(i).getHigh();j++;                                    resultDaily[i][j]=results.getDaily().get(i).getLow();j++;                                }                            }                            temperatureText.setText(resultDaily[0][2]+"℃");                            caseText.setText(resultDaily[0][1]);                            for(int j=0;j<4;){                                //Log.e("resultDaily",resultDaily[0][j]);                                tvFirstDayDate.setText(resultDaily[0][j]);j++;                                tvFirstDayPhe.setText(resultDaily[0][j]);j++;                                tvFirstDayHigh.setText(resultDaily[0][j]);j++;                                tvFirstDayLow.setText(resultDaily[0][j]);j++;                            }                            for(int j=0;j<4;){                                tvSecondDayDate.setText(resultDaily[1][j]);j++;                                tvSecondDayPhe.setText(resultDaily[1][j]);j++;                                tvSecondDayHigh.setText(resultDaily[1][j]);j++;                                tvSecondDayLow.setText(resultDaily[1][j]);j++;                            }                            for(int j=0;j<4;){                                tvThirdDayDate.setText(resultDaily[2][j]);j++;                                tvThirdDayPhe.setText(resultDaily[2][j]);j++;                                tvThirdDayHigh.setText(resultDaily[2][j]);j++;                                tvThirdDayLow.setText(resultDaily[2][j]);j++;                            }                        }                    });                }            });        }    }}

package com.example.xhhweather;import okhttp3.OkHttpClient;import okhttp3.Request;public class HttpUtil {    public static void sendOkHttpRequest(String url,okhttp3.Callback callback){        OkHttpClient client=new OkHttpClient();        Request request=new Request.Builder()                .url(url)                .build();        client.newCall(request).enqueue(callback);    }}

接下来，分析重点
首先看一下心知天气文档，得知需要城市拼音，才能利用api得到不同城市的接口，返回的数据是json格式

访问api需要使用HTTP协议访问网络，那么应该得先想到要用到网络的权限
uses-permission android:name=“android.permission.INTERNET”

这里我用的是OkHttp代替HttpURLConnecion,需要导入依赖
implementation ‘com.squareup.okhttp3:okhttp:3.4.1’

如果不熟悉用法，那就从简单的做起，我介绍怎么简单获得必应图片的每日一图，与本项目有间接的关系（后期用到）

导入这个依赖 implementation ‘com.github.bumptech.glide:glide:4.10.0’，简单快捷可以将图片加载，而且容易理解

建一个HttpUtil类的原因
一个应用程序很可能会在许多地方都使用到网络功能，而发送HTTP请求的代码基本相同，如果每次都去编写，这显然很差劲，将这些通用的网络操作提取到一个公共的类里，并提供一个静态方法

package com.example.atuogetpic;import okhttp3.OkHttpClient;import okhttp3.Request;public class HttpUtil {    public static void sendOkHttpRequest(String address,okhttp3.Callback callback){        OkHttpClient client=new OkHttpClient();        Request request=new Request.Builder()                .url(address)                .build();        client.newCall(request).enqueue(callback);    }}

package com.example.atuogetpic;import androidx.appcompat.app.AppCompatActivity;import android.content.SharedPreferences;import android.os.Bundle;import android.preference.PreferenceManager;import android.util.Log;import android.view.View;import android.widget.Button;import android.widget.ImageView;import com.bumptech.glide.Glide;import java.io.IOException;import okhttp3.Call;import okhttp3.Callback;import okhttp3.HttpUrl;import okhttp3.OkHttpClient;import okhttp3.Request;import okhttp3.Response;import static android.preference.PreferenceManager.getDefaultSharedPreferences;public class MainActivity extends AppCompatActivity {    private ImageView bingPicImg;    private Button btnQ;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        bingPicImg=findViewById(R.id.bing_pic_img);        btnQ=findViewById(R.id.btn);        btnQ.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View view) {                loadBingPic();            }        });    }    /**     * 加载必应每日一图     */    private void loadBingPic(){        final String requestBingPic="http://guolin.tech/api/bing_pic";        HttpUtil.sendOkHttpRequest(requestBingPic, new Callback() {            @Override            public void onResponse(Call call, Response response) throws IOException {                final String bingPic=response.body().string();                SharedPreferences.Editor editor=                        getSharedPreferences("bing_pic",MODE_PRIVATE).edit();                editor.putString("bing_pic",bingPic);                editor.apply();                runOnUiThread(new Runnable() {                    @Override                    public void run() {                        Glide.with(MainActivity.this).load(bingPic).into(bingPicImg);//加载图片                    }                });            }            @Override            public void onFailure(Call call, IOException e) {                e.printStackTrace();            }        });    }}

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:app="http://schemas.android.com/apk/res-auto"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"    tools:context=".MainActivity"    android:orientation="vertical">    <Button        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:id="@+id/btn"        android:text="换图"/>    <ImageView        android:layout_width="match_parent"        android:layout_height="match_parent"        android:id="@+id/bing_pic_img"        android:src="@drawable/bg"/></LinearLayout>

好了，网络请求应该都会了吧

接下来才是重头戏，需要解析json里的数据，但是返回的数据太过复杂（可以看心知天气文档）
可以用gson解析，需要导入依赖
implementation ‘com.google.code.gson:gson:2.8.5’

它主要可以将一段json格式的字符串自动映射成一个对象，不用我们去编写代码解析
{
“results”:[
{
“location”:{“id”:“WTW3SJ5ZBJUY”,“name”:“上海”,“country”:“CN”,“path”:“上海,上海,中国”,“timezone”:“Asia/Shanghai”,“timezone_offset”:"+08:00"}
,“daily”:[
{ “date”:“2019-10-28”,“text_day”:“多云”,“code_day”:“4”,“text_night”:“晴”,“code_night”:“1”,“high”:“21”,“low”:“14”,“precip”:"",“wind_direction”:“西”,“wind_direction_degree”:“270”,“wind_speed”:“16.20”,“wind_scale”:“3”}
,{“date”:“2019-10-29”,“text_day”:“晴”,“code_day”:“0”,“text_night”:“晴”,“code_night”:“1”,“high”:“22”,“low”:“14”,“precip”:"",“wind_direction”:“东北”,“wind_direction_degree”:“45”,“wind_speed”:“25.20”,“wind_scale”:“4”}
,{“date”:“2019-10-30”,“text_day”:“晴”,“code_day”:“0”,“text_night”:“晴”,“code_night”:“1”,“high”:“22”,“low”:“14”,“precip”:"",“wind_direction”:“东”,“wind_direction_degree”:“90”,“wind_speed”:“16.20”,“wind_scale”:“3”}
],
“last_update”:“2019-10-28T11:17:53+08:00”
}
]
}

解析这个json数据
1.{ }里面是一个一个results数组，就应该写成列表，而weather类表示 { }

package com.example.xhhweather.gson;import java.util.List;public class Weather {    private List<WeatherResults> results;//命名一定要与数据中的相同，一定要对应    public List<WeatherResults> getResults() {        return results;    }    public void setResults(List<WeatherResults> results) {        this.results = results;    }    @Override    public String toString() {        return "Weather{" +                "results=" + results +                '}';    }}

2.建一个WeatherResults类，results数组里面又有"location":{}，“daily”:[],“last_update”：一个字符串

package com.example.xhhweather.gson;import java.util.List; public class WeatherResults {     private WeatherResLocation location;//对应location：{}，命名一定要与数据中的相同，一定要对应     private List<WeatherResDaily> daily;//对应daily：数组     private String last_update;//对应"last_update"：一个字符串     public WeatherResLocation getLocation() {         return location;     }     public List<WeatherResDaily> getDaily() {         return daily;     }     public String getLast_update() {         return last_update;     }     public void setLocation(WeatherResLocation location) {         this.location = location;     }     public void setDaily(List<WeatherResDaily> daily) {         this.daily = daily;     }     public void setLast_update(String last_update) {         this.last_update = last_update;     }     @Override     public String toString() {         return "WeatherResults{" +                 "location=" + location +                 ", daily=" + daily +                 ", last_update='" + last_update + '\'' +                 '}';     } }

package com.example.xhhweather.gson;public class WeatherResDaily {    private String date;    private String text_day;    private String code_day;    private String text_night;    private String code_night;    private String high;    private String low;    private String precip;    private String wind_direction;    private String wind_direction_degree;    private String wind_speed;    private String wind_scale;    public String getDate() {        return date;    }    public String getText_day() {        return text_day;    }    public String getCode_day() {        return code_day;    }    public String getText_night() {        return text_night;    }    public String getCode_night() {        return code_night;    }    public String getHigh() {        return high;    }    public String getLow() {        return low;    }    public String getPrecip() {        return precip;    }    public String getWind_direction() {        return wind_direction;    }    public String getWind_direction_degree() {        return wind_direction_degree;    }    public String getWind_speed() {        return wind_speed;    }    public String getWind_scale() {        return wind_scale;    }    public void setDate(String date) {        this.date = date;    }    public void setText_day(String text_day) {        this.text_day = text_day;    }    public void setCode_day(String code_day) {        this.code_day = code_day;    }    public void setText_night(String text_night) {        this.text_night = text_night;    }    public void setCode_night(String code_night) {        this.code_night = code_night;    }    public void setHigh(String high) {        this.high = high;    }    public void setLow(String low) {        this.low = low;    }    public void setPrecip(String precip) {        this.precip = precip;    }    public void setWind_direction(String wind_direction) {        this.wind_direction = wind_direction;    }    public void setWind_direction_degree(String wind_direction_degree) {        this.wind_direction_degree = wind_direction_degree;    }    public void setWind_speed(String wind_speed) {        this.wind_speed = wind_speed;    }    public void setWind_scale(String wind_scale) {        this.wind_scale = wind_scale;    }    @Override    public String toString() {        return "WeatherResDaily{" +                "date='" + date + '\'' +                ", text_day='" + text_day + '\'' +                ", code_day='" + code_day + '\'' +                ", text_night='" + text_night + '\'' +                ", code_night='" + code_night + '\'' +                ", high='" + high + '\'' +                ", low='" + low + '\'' +                ", precip='" + precip + '\'' +                ", wind_direction='" + wind_direction + '\'' +                ", wind_direction_degree='" + wind_direction_degree + '\'' +                ", wind_speed='" + wind_speed + '\'' +                ", wind_scale='" + wind_scale + '\'' +                '}';    }}

package com.example.xhhweather.gson;public class WeatherResLocation {    private String id;    private String name;    private String country;    private String path;    private String timezone;    private String timezone_offset;    public String getId() {        return id;    }    public String getName() {        return name;    }    public String getCountry() {        return country;    }    public String getPath() {        return path;    }    public String getTimezone() {        return timezone;    }    public String getTimezone_offset() {        return timezone_offset;    }    public void setId(String id) {        this.id = id;    }    public void setName(String name) {        this.name = name;    }    public void setCountry(String country) {        this.country = country;    }    public void setPath(String path) {        this.path = path;    }    public void setTimezone(String timezone) {        this.timezone = timezone;    }    public void setTimezone_offset(String timezone_offset) {        this.timezone_offset = timezone_offset;    }    @Override    public String toString() {        return "WeatherResLocation{" +                "id='" + id + '\'' +                ", name='" + name + '\'' +                ", country='" + country + '\'' +                ", path='" + path + '\'' +                ", timezone='" + timezone + '\'' +                ", timezone_offset='" + timezone_offset + '\'' +                '}';    }}

代码可以自动生成，右键点击general（首先要先命名）

Gson gson =new Gson();
Weather weatherInfo=gson.fromJson(weatherData,Weather.class);
weatherData为你发起请求后返回的json数据
这样就可以得到你想要的数据
Android简单版天气预报，显示天气预报（第二步）_第1张图片
Android简单版天气预报，显示天气预报（第二步）_第2张图片
那就先到这了，代码会在下一步开源

Android简单版天气预报，显示天气预报（第二步）

Android简单版天气预报，显示天气预报（第二步）

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