Получение объекта JSON из localhost в android

Question

Мне нужно получить данные с моего локального хоста. Мой код показан ниже:

protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 


// Creating JSON Parser instance 
    JSONParser jParser = new JSONParser(); 
    String url = "http://10.0.2.2:8080/"; 

    // getting JSON string from URL 
    JSONObject json = jParser.getJSONFromUrl(url); 
    try { 
     JSONArray value = json.getJSONArray("one"); 
     String output = value.toString(); 
     TextView textView = new TextView(this); 
     textView.setTextSize(40); 
     textView.setText(output); 

     // Set the text view as the activity layout 
     setContentView(textView); 
    } catch (JSONException e) { 
     // TODO Auto-generated catch block 
     e.printStackTrace(); 
    } 



} 
public class JSONParser { 

    InputStream is = null; 
    JSONObject jObj = null; 
    String json = ""; 

    // constructor 
    public JSONParser() { 

    } 

    public JSONObject getJSONFromUrl(String url) { 

     // Making HTTP request 
     try { 
      // defaultHttpClient 
      DefaultHttpClient httpClient = new DefaultHttpClient(); 
      HttpPost httpPost = new HttpPost(url); 

      HttpResponse httpResponse = httpClient.execute(httpPost); 
      HttpEntity httpEntity = httpResponse.getEntity(); 
      is = httpEntity.getContent();   

     } catch (UnsupportedEncodingException e) { 
      e.printStackTrace(); 
     } catch (ClientProtocolException e) { 
      e.printStackTrace(); 
     } catch (IOException e) { 
      e.printStackTrace(); 
     } 

     try { 
      BufferedReader reader = new BufferedReader(new InputStreamReader(
        is, "iso-8859-1"), 8); 
      StringBuilder sb = new StringBuilder(); 
      String line = null; 
      while ((line = reader.readLine()) != null) { 
       sb.append(line + "\n"); 
      } 
      is.close(); 
      json = sb.toString(); 
     } catch (Exception e) { 
      Log.e("Buffer Error", "Error converting result " + e.toString()); 
     } 

     // try parse the string to a JSON object 
     try { 
      jObj = new JSONObject(json); 
     } catch (JSONException e) { 
      Log.e("JSON Parser", "Error parsing data " + e.toString()); 
     } 

     // return JSON String 
     return jObj; 

    } 
} 

Однако мое приложение падает при открытии. Может кто-нибудь помочь мне, где я иду не так? Для вашей информации, я создал локальный хост, запустив питон скрипт, используя web.py

ошибка Logcat ниже:

08-03 08:55:47.093: E/AndroidRuntime(797): FATAL EXCEPTION: main 
08-03 08:55:47.093: E/AndroidRuntime(797): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.customview/com.example.customview.MainActivity}: android.os.NetworkOnMainThreadException 
08-03 08:55:47.093: E/AndroidRuntime(797): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180) 
08-03 08:55:47.093: E/AndroidRuntime(797): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230) 
08-03 08:55:47.093: E/AndroidRuntime(797): at android.app.ActivityThread.access$600(ActivityThread.java:141) 
08-03 08:55:47.093: E/AndroidRuntime(797): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234) 
08-03 08:55:47.093: E/AndroidRuntime(797): at android.os.Handler.dispatchMessage(Handler.java:99) 
08-03 08:55:47.093: E/AndroidRuntime(797): at android.os.Looper.loop(Looper.java:137) 
08-03 08:55:47.093: E/AndroidRuntime(797): at android.app.ActivityThread.main(ActivityThread.java:5041) 
08-03 08:55:47.093: E/AndroidRuntime(797): at java.lang.reflect.Method.invokeNative(Native Method) 
08-03 08:55:47.093: E/AndroidRuntime(797): at java.lang.reflect.Method.invoke(Method.java:511) 
08-03 08:55:47.093: E/AndroidRuntime(797): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793) 
08-03 08:55:47.093: E/AndroidRuntime(797): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560) 
08-03 08:55:47.093: E/AndroidRuntime(797): at dalvik.system.NativeStart.main(Native Method) 
08-03 08:55:47.093: E/AndroidRuntime(797): Caused by: android.os.NetworkOnMainThreadException 
08-03 08:55:47.093: E/AndroidRuntime(797): at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1117) 
08-03 08:55:47.093: E/AndroidRuntime(797): at libcore.io.BlockGuardOs.connect(BlockGuardOs.java:84) 
08-03 08:55:47.093: E/AndroidRuntime(797): at libcore.io.IoBridge.connectErrno(IoBridge.java:127) 
08-03 08:55:47.093: E/AndroidRuntime(797): at libcore.io.IoBridge.connect(IoBridge.java:112) 
08-03 08:55:47.093: E/AndroidRuntime(797): at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:192) 
08-03 08:55:47.093: E/AndroidRuntime(797): at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:459) 
08-03 08:55:47.093: E/AndroidRuntime(797): at java.net.Socket.connect(Socket.java:842) 
08-03 08:55:47.093: E/AndroidRuntime(797): at org.apache.http.conn.scheme.PlainSocketFactory.connectSocket(PlainSocketFactory.java:119) 
08-03 08:55:47.093: E/AndroidRuntime(797): at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:144) 
08-03 08:55:47.093: E/AndroidRuntime(797): at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164) 
08-03 08:55:47.093: E/AndroidRuntime(797): at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119) 
08-03 08:55:47.093: E/AndroidRuntime(797): at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:360) 
08-03 08:55:47.093: E/AndroidRuntime(797): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:555) 
08-03 08:55:47.093: E/AndroidRuntime(797): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487) 
08-03 08:55:47.093: E/AndroidRuntime(797): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:465) 
08-03 08:55:47.093: E/AndroidRuntime(797): at com.example.customview.MainActivity$JSONParser.getJSONFromUrl(MainActivity.java:75) 
08-03 08:55:47.093: E/AndroidRuntime(797): at com.example.customview.MainActivity.onCreate(MainActivity.java:36) 
08-03 08:55:47.093: E/AndroidRuntime(797): at android.app.Activity.performCreate(Activity.java:5104) 
08-03 08:55:47.093: E/AndroidRuntime(797): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080) 
08-03 08:55:47.093: E/AndroidRuntime(797): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144) 
08-03 08:55:47.093: E/AndroidRuntime(797): ... 11 more 

Answer 1

Вы пытаетесь сделать свою работу сети на Main Тема/UI Thread, поэтому он дает RunTimeException и NetworkOnMainThreadException. Посмотрите на этой линии

08-03 08:55:47.093: E/AndroidRuntime(797): Caused by: android.os.NetworkOnMainThreadException 

ли сетевые операции в фоновом потоке, например использовать AsyncTask.