Android简单的获取网络上的json文件

朴灿烈づ我的快乐病毒、 2022-08-05 13:15 164阅读 0赞

设置网络访问权限

<?xml version="1.0" encoding="utf-8"?>
    <manifest xmlns:android="http://schemas.android.com/apk/res/android"
          package="com.wangjialin.internet.json"
          android:versionCode="1"
          android:versionName="1.0">
        <application android:icon="@drawable/icon" android:label="@string/app_name">
            <activity android:name=".MainActivity"
                      android:label="@string/app_name">
                <intent-filter>
                    <action android:name="android.intent.action.MAIN" />
                    <category android:name="android.intent.category.LAUNCHER" />
                </intent-filter>
            </activity>
    
        </application>
        <uses-sdk android:minSdkVersion="8" />
    
    <uses-permission android:name="android.permission.INTERNET"/>
    
    </manifest>

布局文件：  
mian.xml

<?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:orientation="vertical"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        >
    <ListView  
        android:layout_width="fill_parent" 
        android:layout_height="wrap_content" 
        android:id="@+id/listView"
        />
    </LinearLayout>

布局文件：  
item.xml

<?xml version="1.0" encoding="utf-8"?>
    <LinearLayout
      xmlns:android="http://schemas.android.com/apk/res/android"
      android:orientation="horizontal"
      android:layout_width="fill_parent"
      android:layout_height="wrap_content">
    
      <TextView
       android:layout_width="200dp"
       android:layout_height="wrap_content"
       android:id="@+id/title"
      />
    
        <TextView
       android:layout_width="fill_parent"
       android:layout_height="wrap_content"
       android:id="@+id/timelength"
      />
    </LinearLayout>

编写主MainActivity文件，具体内容如下：

package com.wangjialin.internet.json;
    
    import java.util.ArrayList;
    import java.util.HashMap;
    import java.util.List;
    
    import com.wangjialin.internet.json.domain.News;
    import com.wangjialin.internet.json.service.NewsService;
    
    import android.app.Activity;
    import android.os.Bundle;
    import android.widget.ListView;
    import android.widget.SimpleAdapter;
    
    public class MainActivity extends Activity {
        /** Called when the activity is first created. */
        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.main);
            ListView listView = (ListView) this.findViewById(R.id.listView);
    
            String length = this.getResources().getString(R.string.length);
            try {
                List<News> newes = NewsService.getJSONLastNews();
                List<HashMap<String, Object>> data = new ArrayList<HashMap<String,Object>>();
                for(News news : newes){
                    HashMap<String, Object> item = new HashMap<String, Object>();
                    item.put("id", news.getId());
                    item.put("title", news.getTitle());
                    item.put("timelength", length+ news.getTimelength());
                    data.add(item);
                }
                SimpleAdapter adapter = new SimpleAdapter(this, data, R.layout.item,
                        new String[]{
       "title", "timelength"}, new int[]{R.id.title, R.id.timelength});
                listView.setAdapter(adapter);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

MainActivity 的核心功能是获取数据并显示数据。  
其中获取的数据内的NewsService的具体内容如下：

package com.wangjialin.internet.json.service;
    
    import java.io.InputStream;
    import java.net.HttpURLConnection;
    import java.net.URL;
    import java.util.ArrayList;
    import java.util.List;
    
    import org.json.JSONArray;
    import org.json.JSONObject;
    
    import com.wangjialin.internet.json.domain.News;
    import com.wangjialin.internet.json.utils.StreamTool;
    
    
    
    public class NewsService {
        
    
        /**
         * 获取最新视频资讯
         * @return
         * @throws Exception
         */
        public static List<News> getJSONLastNews() throws Exception{
            String path = "http://192.168.1.100:8080/ServerForJSON/NewsListServlet";
            HttpURLConnection conn = (HttpURLConnection) new URL(path).openConnection();
            conn.setConnectTimeout(5000);
            conn.setRequestMethod("GET");
            if(conn.getResponseCode() == 200){
                InputStream json = conn.getInputStream();
                return parseJSON(json);
            }
            return null;
        }
    
        private static List<News> parseJSON(InputStream jsonStream) throws Exception{
            List<News> list = new ArrayList<News>();
            byte[] data = StreamTool.read(jsonStream);
            String json = new String(data);
            JSONArray jsonArray = new JSONArray(json);
            for(int i = 0; i < jsonArray.length() ; i++){
                JSONObject jsonObject = jsonArray.getJSONObject(i);
                int id = jsonObject.getInt("id");
                String title = jsonObject.getString("title");
                int timelength = jsonObject.getInt("timelength");
                list.add(new News(id, title, timelength));
            }
            return list;
        }
    }

在getJSONLastNews方法中是直接请求搭建好的web服务器，获取JSON输入流后，使用parseJSON方法解析XML数据并最终返回集合数据。  
同时在ＮewsService中用到了一个JavaBean，用于封装XML数据，其名称News，具体内容如下所示：

package com.wangjialin.internet.json.domain;
    
    public class News {
        private Integer id;
        private String title;
        private Integer timelength;
        public News(){}
        public News(Integer id, String title, Integer timelength) {
            this.id = id;
            this.title = title;
            this.timelength = timelength;
        }
        public Integer getId() {
            return id;
        }
        public void setId(Integer id) {
            this.id = id;
        }
        public String getTitle() {
            return title;
        }
        public void setTitle(String title) {
            this.title = title;
        }
        public Integer getTimelength() {
            return timelength;
        }
        public void setTimelength(Integer timelength) {
            this.timelength = timelength;
        }
    
    }