JSON服務調用任何回報

Question

我調用方法在web服務返回字符串「真」或「假」，並使用下面的代碼

String isLogedin = readTwitterFeed(); 
public String readTwitterFeed() { 

     String Result = null; 

     StringBuilder URL = new StringBuilder(); 

     URL.append("http://localhost:1539/WCFService1/Service.svc/Login/"); 
     URL.append(username.getText()); 
     URL.append("/"); 
     URL.append(password.getText()); 

     ///////////////////////////// 
     HttpClient client = new DefaultHttpClient(); 
     HttpGet httpGet = new HttpGet(
       URL.toString()); 




     try { 
      HttpResponse response = client.execute(httpGet); 
      StatusLine statusLine = response.getStatusLine(); 
      int statusCode = statusLine.getStatusCode(); 
      if (statusCode == 200) { 
       HttpEntity entity = response.getEntity(); 
       InputStream content = entity.getContent(); 
       BufferedReader reader = new BufferedReader(
         new InputStreamReader(content)); 

       StringBuilder builder = null ; 
       String line = null; 
       while ((line = reader.readLine()) != null) { 
        builder.append(line); 
       } 

       Result = builder.toString() ; 


      } else { 
       Result = "error"; 
      } 
     } catch (ClientProtocolException e) { 
      Result = "error"; 
      e.printStackTrace(); 
     } catch (IOException e) { 
      Result = "error"; 
      e.printStackTrace(); 
     } 
     return Result; 
    } 

但返回的字符串需要兩個參數總是空

任何知道爲什麼它不返回數據，也不會顯示任何錯誤（我顯示在TextView的返回值），也是我的權限集互聯網一樣，

<uses-permission android:name="android.permission.INTERNET"></uses-permission> 

，並深信服務正在運行

Answer 1

Localhost和127.0.0.1是Android emulated device's自己的Loopback接口，換句話說，您連接使用localhost或127.0.0.1到Android仿真器（不是你的電腦）。如果你想訪問你的開發機器使用10.0.2.2.

一件事情在你的代碼中沒有intialize您StringBuilder builder

初始化它像StringBuilder builder = new StringBuilder();