使用android连接到服务器

Question

我是新来的android和我想连接到json文件，但是当我尝试此代码，但它不连接，当我在我的手机上运行它时，我想工作，它会得到我在logcat的nooo根据我说，当它有问题连接到服务器，谢谢

public class LastFMHelper { 

public static final String LastFMMetroTrackChartUrl= 
     "http://ws.audioscrobbler.com/2.0/?method=geo.getmetrotrackchart&country=united+states&metro=denver&format=json&api_key=bc8ae5008414312b31e8c23f684d67cc"; 
private static final int HTTP_STATUS_OK = 200; 
private static byte[] buff = new byte[1024]; 
private static final String logTag="LastFMHelper"; 


public static class ApiException extends Exception 
{ 
    private static final long serialVersionUID= 1L; 

    public ApiException (String msg) 
    { 
     super(msg); 
    } 

    public ApiException(String msg, Throwable thr) 
    { 
     super(msg, thr); 
    } 

} 

protected static synchronized String downlaodFromServer (String ...params) throws ApiException { 
    String retval= null; 
    String metro = params[0]; 

    String url= LastFMMetroTrackChartUrl + "&metro" +metro; 

    Log.d(logTag,"Fetching"+url); 

    HttpClient client= new DefaultHttpClient(); 
    HttpGet request = new HttpGet(url); 

    try{ 

     HttpResponse responce = client.execute(request); 
     StatusLine status = responce.getStatusLine(); 
     if(status.getStatusCode()!=HTTP_STATUS_OK) 
     { 
      throw new ApiException("Invalid responce from last.fm"+status.toString()); 
     } 

     HttpEntity entity = responce.getEntity(); 
     InputStream ist = entity.getContent(); 
     ByteArrayOutputStream content = new ByteArrayOutputStream(); 

     int readcount =0; 
     while((readcount= ist.read(buff)) != -1) 
     { 
      content.write(buff,0,readcount); 
     } 
     retval= new String (content.toByteArray()); 
    }catch(Exception e){ 
        Log.d(logTag,"noo!!"); 
     throw new ApiException("problem connecting to server " + e.getMessage(),e); 
    } 

    return retval; 



} 

} 

Answer 1

以及你的问题。你没有互联网许可，所以你的应用程序无法连接到服务器。

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

我建议你阅读有关AppManifest这些指南和如何处理权限：

http://developer.android.com/guide/topics/manifest/manifest-intro.html http://developer.android.com/guide/topics/security/permissions.html#permissions

Answer 2

在AppManifest文件标签 - 在<manifest>顶部添加此行如果你不给我们日志，有很多原因可以预测。我只是预测错了： 也许你必须把这个片段放在服务器请求之前：

if (android.os.Build.VERSION.SDK_INT > 9) { 
        StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build(); 
        StrictMode.setThreadPolicy(policy); 
       }