如从网络获取JSON 则需要创建一个工具类，该类返回一个字符串为JSON文本
package com.example.jsonapp;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.Scanner; public class UrlHtmlUtil {
public static String getHtmlJsonByUrl(String urlTemp){
URL url = null;
InputStreamReader input = null;
HttpURLConnection conn;
// JSONObject jsonObj = null;
String a = null;
try {
url = new URL(urlTemp);
conn = (HttpURLConnection) url.openConnection();
input = new InputStreamReader(conn.getInputStream(),"utf-8");
Scanner inputStream = new Scanner(input);
StringBuffer sb = new StringBuffer();
while (inputStream.hasNext()) {
sb.append(inputStream.nextLine());
}
a=sb.toString(); } catch (Exception e) {
System.out.println(e.getMessage());
} return a; } }
然后将文本转为JSONArray，用JSONArray.optJSONObject()来获取JSONObject 对象，接下来便可解析
JSONArray array=new JSONArray(json);
Log.i("转换数组成功","");
for(int i=0;i<array.length();i++)
{
JSONObject jo = array.optJSONObject(i);
if(jo.getString("area").equals(cityName))
{
tv.setText("AQI指数:"+jo.getString("aqi")+"\n地区:"+jo.getString("area")
+"\n空气质量:"+jo.getString("quality")); break;}
if(i==array.length()-1){
tv.setText("抱歉，也并没有找到该城市");
}
}
public void enJson(String json){
try {
JSONTokener jsonParser=new JSONTokener(json);
JSONObject aqi=(JSONObject)jsonParser.nextValue();
String aqistr,areastr,quastr,lvstr,timestr;
aqistr=aqi.getString("aqi");
areastr=aqi.getString("area");
quastr=aqi.getString("quality");
lvstr=levelToLevel(aqi.getString("level"));
timestr=timeToTime(aqi.getString("time"));
tv.setText("地区:"+areastr+"\nAQI："+aqistr+"\n空气质量："+quastr+"\n小贴士："+lvstr+"\n更新时间:"+timestr+"\n点我刷新数据");
}