Android-Json数据解析之空气质量检测

一、JSON基础

1.JSON优点：格式简单，占宽带小，多语言支持

2.JSON缺点：编码必须是Unicode,语法过于严谨

但也因为JSON语法严谨（如四大基础规则），才能支持多语言

3.JSON四大基础规则：

(1)并列数据之间用逗号隔开(",")；

(2)映射用冒号表示(":");

(3)并列数据集合集合(数组)用"[]"表示；

(4)映射的集合(对象)"{}"表示；

---

二、空气质量检测app开发

1.开发环境：

Android Studio 2.1.2(API:18~24)

空气质量检测API(https://www.juhe.cn/docs/api/id/33)

jdk1.8.0_91

2.工程开发：

(1)搭建工程

这里写图片描述

(2)空气质量检测API数据申请

申请api和key请上网站(https://www.juhe.cn/docs/api/id/33), 申请完之后数据将以JSON的格式返回，而读者要做的就是请求数据和解析数据，就是这么简单。

这里写图片描述

返回的数据我只是解析了其中的两个，读者可以根据自己需要解析更多的数据

(3)返回的JSON格式数据

{
    "resultcode": "200",
    "reason": "SUCCESSED!",
    "error_code": 0,
    "result": [
        {
            "citynow": {
                "city": "suzhou",
                "AQI": "77",
                "quality": "良",
                "date": "2014-05-09 14:00"
            },
            "lastTwoWeeks": {
                "1": {
                    "city": "suzhou",
                    "AQI": "100",
                    "quality": "良",
                    "date": "2014-05-08"
                },
                "2": {
                    "city": "suzhou",
                    "AQI": "99",
                    "quality": "良",
                    "date": "2014-05-07"
                },
                "3": {
                    "city": "suzhou",
                    "AQI": "77",
                    "quality": "良",
                    "date": "2014-05-06"
                },
                "4": {
                    "city": "suzhou",
                    "AQI": "75",
                    "quality": "良",
                    "date": "2014-05-05"
                },
                "5": {
                    "city": "suzhou",
                    "AQI": "78",
                    "quality": "良",
                    "date": "2014-05-04"
                },
                "6": {
                    "city": "suzhou",
                    "AQI": "84",
                    "quality": "良",
                    "date": "2014-05-03"
                },
                "7": {
                    "city": "suzhou",
                    "AQI": "135",
                    "quality": "轻度污染",
                    "date": "2014-05-02"
                },
                "8": {
                    "city": "suzhou",
                    "AQI": "126",
                    "quality": "轻度污染",
                    "date": "2014-05-01"
                },
                "9": {
                    "city": "suzhou",
                    "AQI": "87",
                    "quality": "良",
                    "date": "2014-04-30"
                },
                "10": {
                    "city": "suzhou",
                    "AQI": "97",
                    "quality": "良",
                    "date": "2014-04-29"
                },
                "11": {
                    "city": "suzhou",
                    "AQI": "77",
                    "quality": "良",
                    "date": "2014-04-28"
                },
                "12": {
                    "city": "suzhou",
                    "AQI": "84",
                    "quality": "良",
                    "date": "2014-04-27"
                },
                "13": {
                    "city": "suzhou",
                    "AQI": "45",
                    "quality": "优",
                    "date": "2014-04-26"
                },
                "14": {
                    "city": "suzhou",
                    "AQI": "56",
                    "quality": "良",
                    "date": "2014-04-25"
                },
                "15": {
                    "city": "suzhou",
                    "AQI": "83",
                    "quality": "良",
                    "date": "2014-04-24"
                },
                "16": {
                    "city": "suzhou",
                    "AQI": "95",
                    "quality": "良",
                    "date": "2014-04-23"
                },
                "17": {
                    "city": "suzhou",
                    "AQI": "101",
                    "quality": "轻度污染",
                    "date": "2014-04-22"
                }
            },
            "lastMoniData": {
                "1": {
                    "city": "上方山",
                    "AQI": "77",
                    "quality": "良",
                    "PM2.5Hour": "46μg/m³",
                    "PM2.5Day": "46μg/m³",
                    "PM10Hour": "104μg/m³",
                    "lat": "31.247222",
                    "lon": "120.561389"
                },
                "2": {
                    "city": "南门",
                    "AQI": "112",
                    "quality": "轻度污染",
                    "PM2.5Hour": "84μg/m³",
                    "PM2.5Day": "84μg/m³",
                    "PM10Hour": "—μg/m³",
                    "lat": "31.286389",
                    "lon": "120.6275"
                },
                "3": {
                    "city": "彩香",
                    "AQI": "76",
                    "quality": "良",
                    "PM2.5Hour": "46μg/m³",
                    "PM2.5Day": "46μg/m³",
                    "PM10Hour": "101μg/m³",
                    "lat": "31.301944",
                    "lon": "120.590833"
                },
                "4": {
                    "city": "轧钢厂",
                    "AQI": "68",
                    "quality": "良",
                    "PM2.5Hour": "41μg/m³",
                    "PM2.5Day": "41μg/m³",
                    "PM10Hour": "85μg/m³",
                    "lat": "31.326389",
                    "lon": "120.595556"
                },
                "5": {
                    "city": "吴中区",
                    "AQI": "64",
                    "quality": "良",
                    "PM2.5Hour": "46μg/m³",
                    "PM2.5Day": "46μg/m³",
                    "PM10Hour": "—μg/m³",
                    "lat": "31.270278",
                    "lon": "120.612778"
                },
                "6": {
                    "city": "苏州新区",
                    "AQI": "72",
                    "quality": "良",
                    "PM2.5Hour": "46μg/m³",
                    "PM2.5Day": "46μg/m³",
                    "PM10Hour": "93μg/m³",
                    "lat": "31.299444",
                    "lon": "120.543333"
                },
                "7": {
                    "city": "苏州工业园区",
                    "AQI": "82",
                    "quality": "良",
                    "PM2.5Hour": "60μg/m³",
                    "PM2.5Day": "60μg/m³",
                    "PM10Hour": "88μg/m³",
                    "lat": "31.309722",
                    "lon": "120.669167"
                }
            }
        }
    ]
}

读者谨记：在JSON中，"[ ]"指的是数组（集合），"{ }"指的是对象

(3)代码编写

activity_main.xml如下所示

<?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:orientation="vertical"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.administrator.whetherreporter.MainActivity">

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"

            android:text="@string/cityName"
            android:textSize="25sp" />

        <EditText
            android:id="@+id/cityName"
            android:layout_width="297dp"
            android:layout_height="wrap_content" />
    </LinearLayout>

    <Button
        android:id="@+id/submit"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/submit"
        android:textSize="25sp" />

    <ScrollView
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <TextView
            android:id="@+id/show"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:textColor="#000"
            android:textSize="18sp" />
    </ScrollView>
</LinearLayout>

界面比较丑，读者可以根据自己需要修改界面，其实认真写好界面，不失为一款好的应用

strings.xml如下所示

<resources>
    <string name="cityName">城市:</string>
    <string name="submit">提交</string>
    <string name="app_name"></string>
    <string name="city">城市</string>
    <string name="AQI">空气质量指数</string>
    <string name="quality">空气质量</string>
    <string name="time">更新时间</string>
    <string name="loc">地点</string>
    <string name="PM2.5Hour">PM2.5Hour</string>
    <string name="PM2.5Day">PM2.5Day</string>
    <string name="PM10">PM10Hour</string>
    <string name="lat">维度</string>
    <string name="lon">经度</string>
</resources>

MainActivity.java 如下所示

package com.example.administrator.whetherreporter;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

/**
 * Created by Sean on 2016/8/11.
 */

public class MainActivity extends AppCompatActivity {
    private EditText et_cityName;
    private Button btn_submit;
    private TextView tv_show;
    private Task task;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        et_cityName= (EditText) findViewById(R.id.cityName);
        btn_submit= (Button) findViewById(R.id.submit);
        tv_show= (TextView) findViewById(R.id.show);
        btn_submit.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String cityName=et_cityName.getText().toString();
                if (cityName.length()<1){
                    Toast.makeText(MainActivity.this,
                            "请输入城市的名字",Toast.LENGTH_SHORT).show();
                    return;
                }
                else {
                    //开启多线程，一般将比较耗时的操作交给另一条线程
                    task=new Task(MainActivity.this,tv_show);  
                    task.execute(cityName);
                }
            }
        });
    }
}

Taks.java 如下所示

package com.example.administrator.whetherreporter;

import android.content.Context;
import android.os.AsyncTask;
import android.widget.TextView;
import android.widget.Toast;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.util.EntityUtils;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.util.ArrayList;

/**
 * Created by Sean on 2016/8/11.
 */

public class Task extends AsyncTask<String, Void, String> {
    private TextView tv_show;
    private Context context;
    //获取的API接口
    private static final String url = "http://web.juhe.cn:8080/environment/air/cityair";
    //获取的API的key
    private static final String key = "8118a1d36116d6e89f543163055d7530";

    public Task(Context context, TextView tv_show) {
        this.context = context;
        this.tv_show = tv_show;
    }

    /***
     *
     * 通过API请求数据
     * @param strings :从主线程中执行子线程传入的字符串，即cityName
     * @return        :请求API之后返回的JSON格式数据
     */
    @Override
    protected String doInBackground(String... strings) {
        String city = strings[0];
        ArrayList<NameValuePair> firstList = new ArrayList<NameValuePair>();
        //设置访问文本类型
        firstList.add(new BasicNameValuePair("Content-Type", "text/html,charset=utf-8"));

        String targetUrl = url;
        //请求的参数
        ArrayList<NameValuePair> paramsList = new ArrayList<NameValuePair>();
        paramsList.add(new BasicNameValuePair("city", city));
        paramsList.add(new BasicNameValuePair("key", key));

        for (int i = 0; i < paramsList.size(); i++) {
            NameValuePair nowPair = paramsList.get(i);
            String value = nowPair.getValue();
            try {
                value = URLEncoder.encode(value, "utf-8");
            } catch (UnsupportedEncodingException e) {
                e.printStackTrace();
            }
            if (i == 0) {
                targetUrl += ("?" + nowPair.getName() + "=" + value);
            } else {
                targetUrl += ("&" + nowPair.getName() + "=" + value);
            }
        }
        //以Get的形式访问
        HttpGet httpGet = new HttpGet(targetUrl);
        try {
            for (int i = 0; i < firstList.size(); i++) {
                    httpGet.addHeader(firstList.get(i).getName(),       firstList.get(i).getValue());
            }

            HttpClient httpClient = new DefaultHttpClient();

            HttpResponse httpResponse = httpClient.execute(httpGet);
            if (httpResponse.getStatusLine().getStatusCode()==200){
                String result= EntityUtils.toString(httpResponse.getEntity());
                return result;
            }
            else
                return null;
        } catch (IOException e) {
            e.printStackTrace();
        }


        return null;
    }

    /***
     *
     * 解析返回的数据
     * @param s   :请求之后返回的数据
     */
    @Override
    protected void onPostExecute(String s) {
        super.onPostExecute(s);
        if (s!=null){
            try {
                JSONObject jsonObject=new JSONObject(s);
                int resultCode=jsonObject.getInt("resultcode");
                if (resultCode==200){
                    JSONArray resultArray=jsonObject.getJSONArray("result");
                    JSONObject resultJsonObject = resultArray.getJSONObject(0);
                    JSONObject A= (JSONObject) resultJsonObject.get("citynow");
                    JSONObject B= (JSONObject) resultJsonObject.get("lastMoniData");

                    String division="---------------------------------------------";
                    
                    String output=
                             context.getString(R.string.city)+":"+A.optString("city")+"\n"
                            +context.getString(R.string.AQI)+":"+A.optString("AQI")+"\n"
                            +context.getString(R.string.quality)+":"+A.optString("quality")+"\n"
                            +context.getString(R.string.time)+":"+A.optString("date")+"\n"
                            +division+"\n"
                            +"监测点数据"+"\n";
                    for (int i=0;i<B.length();i++) {
                        int w=i+1;
                        String n=Integer.toString(w);
                        JSONObject C= (JSONObject) B.get(n);
                        output=output
                                + context.getString(R.string.loc) + ":" + C.optString("city") + "\n"
                                + context.getString(R.string.AQI) + ":" + C.optString("AQI") + "\n"
                                + context.getString(R.string.quality) + ":" + C.optString("quality") + "\n"
                                + context.getString(R.string.PM10) + ":" + C.optString("PM10Hour") + "\n"
                                + context.getString(R.string.PM2_5Hour) + ":" + C.optString("PM2.5Hour") + "\n"
                                + context.getString(R.string.PM2_5Day) + ":" + C.optString("PM2.5Day") + "\n"
                                + context.getString(R.string.lat) + ":" + C.optString("lat") + "\n"
                                + context.getString(R.string.lon) + ":" + C.optString("lon") + "\n";
                    }
                    tv_show.setText(output);
                }
                else if (resultCode==202){
                    String reason=jsonObject.getString("reason");
                    tv_show.setText(reason);
                }
                else{
                    Toast.makeText(context, "查询失败",
                            Toast.LENGTH_LONG).show();
                    tv_show.setText("");
                }
            } catch (JSONException e) {
                e.printStackTrace();
            }

        }
        else {
            Toast.makeText(context, "查询失败",
                    Toast.LENGTH_LONG).show();
            tv_show.setText("");
        }
    }
}

*注意：类NameValuePair在Android API22的是后就已经过时了，可以用到类ContentValue来代替，使用方式如下图所示 *

这里写图片描述

HttpGet 和 HttpClient 需要读者自己导入第三方包

这里写图片描述

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三、测试

这里写图片描述
这里写图片描述

由于API本身的局限性，所以有些地方数据可能有问题，请包涵！

---

That's all , 感谢您的阅读，之后我会将我的项目发布到GitHub。

请大家尊重原创者版权，转载请标明出处 http://blog.csdn.net/AAAAA_Sean_M/article/details/52183277

参考：http://blog.csdn.net/hantangsongming/article/details/42234293