android.os.networkNetworkOnMainThreadException当尝试http连接

Question

因此，我得到一个android.os.NetworkOnMainThreadException，我似乎无法找到什么是错的。我已经在搜索它，并且大多数人似乎得到它，因为他们试图在主线程上访问网络。我创建了“AsyncTask”来创建一个不同的线程，并让它在后台运行，所以除非我做得不正确，否则我不确定我能改变什么。下面

package rafa.weatherapp; 

import java.io.IOException; 
import java.io.InputStream; 
import java.io.InputStreamReader; 
import java.io.Reader; 
import java.net.HttpURLConnection; 
import java.net.URL; 

import android.app.Activity; 
import android.os.AsyncTask; 
import android.os.Bundle; 
import android.os.StrictMode; 
import android.util.Log; 
import android.widget.TextView; 


public class MainActivity extends Activity 

{ 

    TextView http; 
/** Called when the activity is first created. 
* @param runnable */ 

    @Override 
    public void onCreate(Bundle savedInstanceState) 
    { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main);   
     http = (TextView) findViewById(R.id.http_display); 

     GetHttp yes = new GetHttp(); 

     http.setText(yes.doInBackground()); 



     //connect.execute(); 


    } 


    private class GetHttp extends AsyncTask<Object, Void, String> 
    { 
     @Override 
     protected String doInBackground(Object... arg0) { 
      int responseCode= -1; 
      int identity = 0; 
      try{ 
       //define URL that information will come in from 
       URL url = new URL("http://openweathermap.org/data/2.3/forecast/city?id=524901&APPID=111111111"); 
       //establish HttpURL Connection 
       HttpURLConnection connection = (HttpURLConnection) url.openConnection(); 
       connection.connect(); 

       //check to make sure it connected 
       responseCode=connection.getResponseCode(); 
       if(responseCode == HttpURLConnection.HTTP_OK); 

       //Take in the data 
       InputStream in = connection.getInputStream(); 
       Reader reader = new InputStreamReader(in); 
       int contentLength = connection.getContentLength();   
       char charArray[] = new char[contentLength]; 

       reader.read(charArray); 
       String responseData = new String(charArray); 

       Log.v(responseData, null); 





      } 
      catch(IOException e){ 
       return "Unable to retrieve webpage, URL may be invalid"; 
      } 


      return null; 

     } 

    }; 
} 

我的错误是：

04-30 15:33:02.371: W/dalvikvm(17021): threadid=1: thread exiting with uncaught exception (group=0x4206d700) 
04-30 15:33:02.376: E/AndroidRuntime(17021): FATAL EXCEPTION: main 
04-30 15:33:02.376: E/AndroidRuntime(17021): java.lang.RuntimeException: Unable to start activity ComponentInfo{rafa.weatherapp/rafa.weatherapp.MainActivity}: android.os.NetworkOnMainThreadException 
04-30 15:33:02.376: E/AndroidRuntime(17021): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2308) 
04-30 15:33:02.376: E/AndroidRuntime(17021): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2362) 
04-30 15:33:02.376: E/AndroidRuntime(17021): at android.app.ActivityThread.access$700(ActivityThread.java:168) 
04-30 15:33:02.376: E/AndroidRuntime(17021): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1329) 
04-30 15:33:02.376: E/AndroidRuntime(17021): at android.os.Handler.dispatchMessage(Handler.java:99) 
04-30 15:33:02.376: E/AndroidRuntime(17021): at android.os.Looper.loop(Looper.java:137) 
04-30 15:33:02.376: E/AndroidRuntime(17021): at android.app.ActivityThread.main(ActivityThread.java:5493) 
04-30 15:33:02.376: E/AndroidRuntime(17021): at java.lang.reflect.Method.invokeNative(Native Method) 
04-30 15:33:02.376: E/AndroidRuntime(17021): at java.lang.reflect.Method.invoke(Method.java:525) 
04-30 15:33:02.376: E/AndroidRuntime(17021): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1209) 
04-30 15:33:02.376: E/AndroidRuntime(17021): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1025) 
04-30 15:33:02.376: E/AndroidRuntime(17021): at dalvik.system.NativeStart.main(Native Method) 
04-30 15:33:02.376: E/AndroidRuntime(17021): Caused by: android.os.NetworkOnMainThreadException 
04-30 15:33:02.376: E/AndroidRuntime(17021): at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1144) 
04-30 15:33:02.376: E/AndroidRuntime(17021): at java.net.InetAddress.lookupHostByName(InetAddress.java:385) 
04-30 15:33:02.376: E/AndroidRuntime(17021): at java.net.InetAddress.getAllByNameImpl(InetAddress.java:236) 
04-30 15:33:02.376: E/AndroidRuntime(17021): at java.net.InetAddress.getAllByName(InetAddress.java:214) 
04-30 15:33:02.376: E/AndroidRuntime(17021): at libcore.net.http.HttpConnection.<init>(HttpConnection.java:70) 
04-30 15:33:02.376: E/AndroidRuntime(17021): at libcore.net.http.HttpConnection.<init>(HttpConnection.java:50) 
04-30 15:33:02.376: E/AndroidRuntime(17021): at libcore.net.http.HttpConnection$Address.connect(HttpConnection.java:340) 
04-30 15:33:02.376: E/AndroidRuntime(17021): at libcore.net.http.HttpConnectionPool.get(HttpConnectionPool.java:87) 
04-30 15:33:02.376: E/AndroidRuntime(17021): at libcore.net.http.HttpConnection.connect(HttpConnection.java:128) 
04-30 15:33:02.376: E/AndroidRuntime(17021): at libcore.net.http.HttpEngine.openSocketConnection(HttpEngine.java:316) 
04-30 15:33:02.376: E/AndroidRuntime(17021): at libcore.net.http.HttpEngine.connect(HttpEngine.java:311) 
04-30 15:33:02.376: E/AndroidRuntime(17021): at libcore.net.http.HttpEngine.sendSocketRequest(HttpEngine.java:290) 
04-30 15:33:02.376: E/AndroidRuntime(17021): at libcore.net.http.HttpEngine.sendRequest(HttpEngine.java:240) 
04-30 15:33:02.376: E/AndroidRuntime(17021): at libcore.net.http.HttpURLConnectionImpl.connect(HttpURLConnectionImpl.java:81) 
04-30 15:33:02.376: E/AndroidRuntime(17021): at rafa.weatherapp.MainActivity$GetHttp.doInBackground(MainActivity.java:58) 
04-30 15:33:02.376: E/AndroidRuntime(17021): at rafa.weatherapp.MainActivity.onCreate(MainActivity.java:36) 
04-30 15:33:02.376: E/AndroidRuntime(17021): at android.app.Activity.performCreate(Activity.java:5372) 
04-30 15:33:02.376: E/AndroidRuntime(17021): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1104) 
04-30 15:33:02.376: E/AndroidRuntime(17021): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2270) 
04-30 15:33:02.376: E/AndroidRuntime(17021): ... 11 more 
04-30 15:38:02.746: I/Process(17021): Sending signal. PID: 17021 SIG: 9 

Answer 1

不要叫doInBackground()自己。而是​​的AsyncTask。该框架在后台线程上为您调用doInBackground()。使用结果更新您的用户界面onPostExecute()。