0

我正在尝试从网站检索数据，但我的应用程序不断崩溃。我已将问题归结为 openStream() 命令。我正在使用的类定义如下。我无法弄清楚我做错了什么。任何建议表示赞赏。

    private class MyAsyncTask extends AsyncTask<Void, Void, Void>{

    //execute on background (out of the UI thread)
    protected void doInBackground() {
        URL url = null;
        try {
            url = new URL("URL is in here");

            BufferedInputStream bis = new BufferedInputStream(url.openStream());
            byte[] buffer = new byte[1024];
            StringBuilder sb = new StringBuilder();
            int bytesRead = 0;
            while((bytesRead = bis.read(buffer)) > 0) {
                String text = new String(buffer, 0, bytesRead);
                sb.append(text);
            }
            bis.close();


        } catch (MalformedURLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }

    @Override
    protected Void doInBackground(Void... arg0) {
        // TODO Auto-generated method stub
        return null;
    }
}

我的清单文件中确实有 Internet 权限。再次感谢任何帮助。

以下是 logcat 中显示的错误。

07-11 11:26:31.110: E/AndroidRuntime(9259): 致命异常: main 07-11 11:26:31.110: E/AndroidRuntime(9259): java.lang.RuntimeException: 无法启动活动 ComponentInfo{com. example.annarbormap/com.example.annarbormap.MapActivity}：android.os.NetworkOnMainThreadException 07-11 11:26:31.110：E/AndroidRuntime(9259)：在 android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2246) 07 -11 11:26:31.110: E/AndroidRuntime(9259): 在 android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2296) 07-11 11:26:31.110: E/AndroidRuntime(9259): 在 android.app .ActivityThread.access$700(ActivityThread.java:151) 07-11 11:26:31.110: E/AndroidRuntime(9259): 在 android.app.ActivityThread$H.handleMessage(ActivityThread.java:1281) 07-11 11: 26:31.110：E/AndroidRuntime(9259)：在 android.os.Handler。dispatchMessage(Handler.java:99) 07-11 11:26:31.110: E/AndroidRuntime(9259): 在 android.os.Looper.loop(Looper.java:137) 07-11 11:26:31.110: E/ AndroidRuntime(9259): 在 android.app.ActivityThread.main(ActivityThread.java:5293) 07-11 11:26:31.110: E/AndroidRuntime(9259): 在 java.lang.reflect.Method.invokeNative(Native Method) 07-11 11:26:31.110: E/AndroidRuntime(9259): 在 java.lang.reflect.Method.invoke(Method.java:511) 07-11 11:26:31.110: E/AndroidRuntime(9259): 在com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1102) 07-11 11:26:31.110: E/AndroidRuntime(9259): at com.android.internal.os.ZygoteInit.main(ZygoteInit .java:869) 07-11 11:26:31.110: E/AndroidRuntime(9259): at dalvik.system.NativeStart.main(Native Method) 07-11 11:26:31.110: E/AndroidRuntime(9259): Caused作者：android.os。NetworkOnMainThreadException 07-11 11:26:31.110: E/AndroidRuntime(9259): 在 android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1118) 07-11 11:26:31.110: E/AndroidRuntime(9259):在 java.net.InetAddress.lookupHostByName(InetAddress.java:385) 07-11 11:26:31.110: E/AndroidRuntime(9259): 在 java.net.InetAddress.getAllByNameImpl(InetAddress.java:236) 07-11 11 :26:31.110: E/AndroidRuntime(9259): at java.net.InetAddress.getAllByName(InetAddress.java:214) 07-11 11:26:31.110: E/AndroidRuntime(9259): at libcore.net.http。 HttpConnection.(HttpConnection.java:70) 07-11 11:26:31.110: E/AndroidRuntime(9259): 在 libcore.net.http.HttpConnection.(HttpConnection.java:50) 07-11 11:26:31.110: E/AndroidRuntime(9259)：在 libcore.net.http.HttpConnection$Address.connect(HttpConnection.java:340) 07-11 11:26:31。110: E/AndroidRuntime(9259): 在 libcore.net.http.HttpConnectionPool.get(HttpConnectionPool.java:87) 07-11 11:26:31.110: E/AndroidRuntime(9259): 在 libcore.net.http.HttpConnection .connect(HttpConnection.java:128) 07-11 11:26:31.110: E/AndroidRuntime(9259): 在 libcore.net.http.HttpEngine.openSocketConnection(HttpEngine.java:316) 07-11 11:26:31.110 : E/AndroidRuntime(9259): 在 libcore.net.http.HttpsURLConnectionImpl$HttpsEngine.makeSslConnection(HttpsURLConnectionImpl.java:461) 07-11 11:26:31.110: E/AndroidRuntime(9259): 在 libcore.net.http。 HttpsURLConnectionImpl$HttpsEngine.connect(HttpsURLConnectionImpl.java:433) 07-11 11:26:31.110: E/AndroidRuntime(9259): 在 libcore.net.http.HttpEngine.sendSocketRequest(HttpEngine.java:290) 07-11 11: 26:31.110：E/AndroidRuntime(9259)：在 libcore.net.http.HttpEngine。sendRequest(HttpEngine.java:240) 07-11 11:26:31.110: E/AndroidRuntime(9259): 在 libcore.net.http.HttpURLConnectionImpl.getResponse(HttpURLConnectionImpl.java:282) 07-11 11:26:31.110: E/AndroidRuntime(9259): 在 libcore.net.http.HttpURLConnectionImpl.getInputStream(HttpURLConnectionImpl.java:177) 07-11 11:26:31.110: E/AndroidRuntime(9259): 在 libcore.net.http.HttpsURLConnectionImpl.getInputStream (HttpsURLConnectionImpl.java:271) 07-11 11:26:31.110: E/AndroidRuntime(9259): at java.net.URL.openStream(URL.java:462) 07-11 11:26:31.110: E/AndroidRuntime (9259): 在 com.example.annarbormap.MapActivity$MyAsyncTask.doInBackground(MapActivity.java:77) 07-11 11:26:31.110: E/AndroidRuntime(9259): 在 com.example.annarbormap.MapActivity.onCreate( MapActivity.java:48) 07-11 11:26:31.110: E/AndroidRuntime(9259): 在 android.app.Activity.performCreate(Activity.java:5250) 07-11 11:26:31.110: E/AndroidRuntime(9259): 在 android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1097) 07-11 11:26: 31.110: E/AndroidRuntime(9259): 在 android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2210) 07-11 11:26:31.110: E/AndroidRuntime(9259): ... 11 更多

4

1 回答 1

4

NetworkOnMainThreadException

您创建了自己的 doInBackground 方法，但 Internet 连接必须仅在后台，请将您的代码放入覆盖的方法 doInbackground！请参见下面的示例：

在后台实现获取数据，在 opPostExecute 方法中 - 将数据设置为视图。

private class MyAsyncTask extends AsyncTask<Void, Void, Void>{

    @Override
    protected Void doInBackground(Void... arg0) {
       URL url = null;
       try {
           url = new URL("URL is in here");

           BufferedInputStream bis = new BufferedInputStream(url.openStream());
           byte[] buffer = new byte[1024];
           StringBuilder sb = new StringBuilder();
           int bytesRead = 0;
           while((bytesRead = bis.read(buffer)) > 0) {
               String text = new String(buffer, 0, bytesRead);
               sb.append(text);
           }
           bis.close();

       } catch (MalformedURLException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (IOException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       }

       return yourResult;
    }
}

或者

private class MyAsyncTask extends AsyncTask<Void, Void, Void>{

    @Override
    protected Void doInBackground(Void... arg0) {
        doInBackground();   //your methods
        return null;
    }

    protected void doInBackground() {
        URL url = null;
        try {
            url = new URL("URL is in here");

            BufferedInputStream bis = new BufferedInputStream(url.openStream());
            byte[] buffer = new byte[1024];
            StringBuilder sb = new StringBuilder();
            int bytesRead = 0;
            while((bytesRead = bis.read(buffer)) > 0) {
               String text = new String(buffer, 0, bytesRead);
               sb.append(text);
            }
           bis.close();


       } catch (MalformedURLException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (IOException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       }

   }

}

希望，我帮助你。

于 2013-07-11T15:45:08.860 回答