使用Gson解析json并且加载json中的网络图片
本人刚入行安卓大半年，虽说经验很少，但是我还是想把自己平时做项目过程中的一些东西记录下来，一来大家互相学习，二来自己也能看到自己进步的脚印。
好了，言归正传，这次主要就是一个使用Gson来解析json的例子。先给大家上图：
其实解析json的方法有很多，之前使用JSONObject和JSONArray来解析json也挺不错，可是相比Gson就会显得有些麻烦了。Gson库的下载连接：点击打开链接。我是在本地的tomcat下自己写了一个json，没安装tomcat的请先下载一个tomcat：点击打开链接，下载完毕不需要安装，解压即可使用（需要配置jdk的环境变量），在tomcat的目录webapps\ROOT里面新建一个weather.html页面，json代码如下：
{
"error": 0,
"status": "success",
"date": "2015-03-10",
"results": [
{
"currentCity": "北京",
"weather_data": [
{
"date": "周一(今天, 实时：19℃)",
"dayPictureUrl": "http://api.map.baidu.com/images/weather/day/dayu.png",
"nightPictureUrl": "http://api.map.baidu.com/images/weather/night/dayu.png",
"weather": "大雨",
"wind": "东南风5-6级",
"temperature": "18℃"
},
{
"date": "周二",
"dayPictureUrl": "http://api.map.baidu.com/images/weather/day/zhenyu.png",
"nightPictureUrl": "http://api.map.baidu.com/images/weather/night/duoyun.png",
"weather": "阵雨转多云",
"wind": "西北风4-5级",
"temperature": "21 ~ 14℃"
},
{
"date": "周三",
"dayPictureUrl": "http://api.map.baidu.com/images/weather/day/leizhenyu.png",
"nightPictureUrl": "http://api.map.baidu.com/images/weather/night/leizhenyu.png",
"weather": "雷阵雨",
"wind": "西北风4-5级",
"temperature": "22 ~ 18℃"
},
{
"date": "周四",
"dayPictureUrl": "http://api.map.baidu.com/images/weather/day/qing.png",
"nightPictureUrl": "http://api.map.baidu.com/images/weather/night/qing.png",
"weather": "晴",
"wind": "东南风2级",
"temperature": "28℃"
}
]
}
]
} 然后在tomcat的bin目录下双击打开startup.bat即可开启tomcat服务器，此时打开浏览器，在浏览器地址栏输入：http://192.168.1.14:8080/weather.html，这里你们需要改成你们自己的ip地址，如果页面显示如下则说明服务器端已ok
此时我们需要先写一个javaBean，如果是多层嵌套的话建议写成内部类的形式（注意在javaBean中定义的变量一定要和json中的键保持一致，否则会解析不出来），javaBean代码如下：Status.java
package com.example.gsonparsejson;
import java.util.List;
public class Status {
private String error;
private String status;
private String date;
private List<results> results;
public String getError() {
return error;
}
public void setError(String error) {
this.error = error;
}
public String getStatus() {
return status;
}
public void setStatus(String status) {
this.status = status;
}
public String getDate() {
return date;
}
public void setDate(String date) {
this.date = date;
}
public List<results> getResult() {
return results;
}
public void setResult(List<results> results) {
this.results = results;
}
@Override
public String toString() {
return "Status [error=" + error + ", status=" + status + ", date="
+ date + ", result=" + results + "]";
}
public class results {
private String currentCity;
private List<weather_data> weather_data;
public String getCurentCity() {
return currentCity;
}
public void setCurentCity(String currentCity) {
this.currentCity = currentCity;
}
public List<weather_data> getWeather_data() {
return weather_data;
}
public void setWeather_data(List<weather_data> weather_data) {
this.weather_data = weather_data;
}
@Override
public String toString() {
return "results [curentCity=" + currentCity + ", weather_data="
+ weather_data + "]";
}
public class weather_data {
private String date;
private String dayPictureUrl;
private String nightPictureUrl;
private String weather;
private String wind;
private String temperature;
public String getDate() {
return date;
}
public void setDate(String date) {
this.date = date;
}
public String getDayPictureUrl() {
return dayPictureUrl;
}
public void setDayPictureUrl(String dayPictureUrl) {
this.dayPictureUrl = dayPictureUrl;
}
public String getNightPictureUrl() {
return nightPictureUrl;
}
public void setNightPictureUrl(String nightPictureUrl) {
this.nightPictureUrl = nightPictureUrl;
}
public String getWeather() {
return weather;
}
public void setWeather(String weather) {
this.weather = weather;
}
public String getWind() {
return wind;
}
public void setWind(String wind) {
this.wind = wind;
}
public String getTemperature() {
return temperature;
}
public void setTemperature(String temperature) {
this.temperature = temperature;
}
@Override
public String toString() {
return "weather_data [date=" + date + ", dayPictureUrl="
+ dayPictureUrl + ", nightPictureUrl="
+ nightPictureUrl + ", weather=" + weather + ", wind="
+ wind + ", temperature=" + temperature + "]";
}
}
}
}
接下来就是开始解析了，在activity的oncreate方法中开启一个线程：
new Thread() {
public void run() {
String path = "http://192.168.1.14:8080/weather.html";
String jsonString = HttpUtils.getJsonContent(path);// 从网络获取数据
Gson gson = new Gson();
fromJson = gson.fromJson(jsonString, Status.class);
result = fromJson.getResult();
weather = fromJson.getResult().get(0).getWeather_data();
mHandler.sendEmptyMessage(000);
};
}.start();我是先从网络上获取到数据然后直接用gson.fromjson来解析，这个gson做的还是蛮厉害的。此方法唯一的不好就是需要把json数据从网上copy下来，如果json数据非常大的话，那就要用别的方式获取数据了，推荐可以用Volley 点击打开链接，该博主有详细的介绍，我再贴上我获取数据的工具类：HttpUtils.java
package com.example.gsonparsejson;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
//通过HttpURLCnnection获取链接里的数据，放到流里，然后把流里面的数据转换为字符串
public class HttpUtils {
public HttpUtils() {
}
public static String getJsonContent(String url_path) {
try {
URL url = new URL(url_path);
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setConnectTimeout(3000);
connection.setRequestMethod("GET");
connection.setDoInput(true);
int code = connection.getResponseCode();
if (code == 200) {
return changeInputStream(connection.getInputStream());
}
} catch (Exception e) {
}
return "";
}
private static String changeInputStream(InputStream inputStream) {
// TODO Auto-generated method stub
String jsonString = "";
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
int len = 0;
byte[] data = new byte[1024];
try {
while ((len = inputStream.read(data)) != -1) {
outputStream.write(data, 0, len);
}
jsonString = new String(outputStream.toByteArray());
outputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
return jsonString;
}
}到此为止就已经拿到了json中的数据了，我把他存放在weather这个集合中，之后就是给listview加载adapter设置数据了，我自己写了一个adapter继承自BaseAdapter，里面最重要的方法就是getview了：
@Override
public View getView(int position, View convertView, ViewGroup parent) {
weather_data data = weather.get(position);
View view;
final ViewHolder holder;
if (convertView != null) {
view = convertView;
holder = (ViewHolder) view.getTag();
} else {
view = View.inflate(MainActivity.this, R.layout.weather_item,null);
holder = new ViewHolder();
holder.date = (TextView) view.findViewById(R.id.date);
holder.wea = (TextView) view.findViewById(R.id.wea);
holder.wind = (TextView) view.findViewById(R.id.wind);
holder.tem = (TextView) view.findViewById(R.id.tem);
holder.daypicture = (ImageView) view.findViewById(R.id.daypicture);
holder.nightpicture = (ImageView) view.findViewById(R.id.nightpicture);
view.setTag(holder);
}
holder.date.setText(data.getDate());
holder.wea.setText(data.getWeather());
holder.wind.setText(data.getWind());
holder.tem.setText(data.getTemperature());
try {
URL dayurl = new URL(data.getDayPictureUrl());
URL nighturl = new URL(data.getNightPictureUrl());
Utils.onLoadImage(dayurl, new OnLoadImageListener() {
@Override
public void OnLoadImage(Bitmap bitmap, String bitmapPath) {
if(bitmap!=null){
holder.daypicture.setImageBitmap(bitmap);
}
}
});
Utils.onLoadImage(nighturl, new OnLoadImageListener() {
@Override
public void OnLoadImage(Bitmap bitmap, String bitmapPath) {
if(bitmap!=null){
holder.nightpicture.setImageBitmap(bitmap);
}
}
});
} catch (Exception e) {
e.printStackTrace();
}
return view;
}在该方法里从weather集合里拿到了对应位置的数据然后设置Text就好了，在设置imageview时我是加载了json里面链接的图片，详情可以参考： 点击打开链接，稍后我会把整个项目的连接地址给大家，有兴趣的可以下载来看看，也欢迎大家对我进行指点。最后别忘了在清单文件中添加权限：<uses-permission android:name="android.permission.INTERNET" />
源码下载地址： 点击打开链接
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