Java 尝试访问网页时，应用程序为FC

我的应用程序中有以下代码：

DefaultHttpClient httpClient = new DefaultHttpClient();
HttpGet httpGet = new HttpGet("http://www.pagesbyz.com");
ResponseHandler<String> resHandler = new BasicResponseHandler();
try {
    String page = httpClient.execute(httpGet, resHandler);
    Toast.makeText(getApplicationContext(), "SUCCESS", 2000).show();
} catch (ClientProtocolException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
} catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
}

---

你知道怎么解决吗？谢谢

您面临的问题是，正如NetworkOnMainThreadException所述，您正在主线程上运行网络代码

查看此问题的答案，了解如何使用AsyncTask避免这种情况：

这篇博文深入解释了这一例外情况：

最后，官方NetworkOnMainThreadException文档可以在这里找到：

这是解释。您应该使用用于网络访问的线程或HandlerThread。自API 11以来，禁止在主（UI）线程上进行网络访问

您可以尝试以下方法：

private class HttpTask extends AsyncTask<String, Void, Void>{
    @Override
    protected Void doInBackground(String... params) {
        String url = params[0];
        DefaultHttpClient httpClient = new DefaultHttpClient();
        HttpGet httpGet = new HttpGet(url);
        ResponseHandler<String> resHandler = new BasicResponseHandler();
        try {
            String page = httpClient.execute(httpGet, resHandler);
        } catch (ClientProtocolException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return null;
    }

    @Override
    protected void onPostExecute(Void result) {
        super.onPostExecute(result);
        Toast.makeText(getApplicationContext(), "SUCCESS", 2000).show();
    }
}

---

您必须从非UI线程发出请求，例如使用AsyncTask或？扩展线程

您正试图直接从活动中从服务器获取结果。这是允许的，直到2.x。从蜂巢开始，它就被引入了。由于此操作可能需要很长时间，它将阻塞UI线程，并且可能会显示。对于任何耗时的操作，应使用单独的线程

你可以用。它与您的活动在不同的线程上运行

---

在AsyncTask中，您可以执行所需的操作，并将其结果传递给该类的成员，根据该类，您可以显示要在应用程序中显示的Toast消息

在Google上搜索android.os.NetworkOnMainThreadException在读取android堆栈跟踪时，请始终查找“原因：”。可能有任何数字。如果存在，那么堆栈跟踪的实际有用位将从最后一个开始。谢谢。我使用了AsyncTask，它解决了这个问题。问题，如果我不想访问网站，而是想从web服务器上的文件中检索一些数据，并使用这些数据在我的应用程序中创建某种图表，该怎么办。你能帮我吗？或者给我指出正确的方向吗？很高兴我能帮上忙。如果您需要广泛的帮助，您应该为您的请求创建一个单独的问题，或者使用谷歌搜索它，但是为了开始，您可能正在考虑使用类似HttpClient的东西来发出请求（），并使用客户端的execute方法获取HttpResponse。快乐编码；-）

11-04 11:59:14.137: E/AndroidRuntime(11052): FATAL EXCEPTION: main
11-04 11:59:14.137: E/AndroidRuntime(11052): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.test.testing/com.test.testing.AndroidFragmentation}: android.os.NetworkOnMainThreadException
11-04 11:59:14.137: E/AndroidRuntime(11052):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2306)
11-04 11:59:14.137: E/AndroidRuntime(11052):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2356)
11-04 11:59:14.137: E/AndroidRuntime(11052):    at android.app.ActivityThread.access$600(ActivityThread.java:150)
11-04 11:59:14.137: E/AndroidRuntime(11052):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1244)
11-04 11:59:14.137: E/AndroidRuntime(11052):    at android.os.Handler.dispatchMessage(Handler.java:99)
11-04 11:59:14.137: E/AndroidRuntime(11052):    at android.os.Looper.loop(Looper.java:137)
11-04 11:59:14.137: E/AndroidRuntime(11052):    at android.app.ActivityThread.main(ActivityThread.java:5195)
11-04 11:59:14.137: E/AndroidRuntime(11052):    at java.lang.reflect.Method.invokeNative(Native Method)
11-04 11:59:14.137: E/AndroidRuntime(11052):    at java.lang.reflect.Method.invoke(Method.java:511)
11-04 11:59:14.137: E/AndroidRuntime(11052):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:795)
11-04 11:59:14.137: E/AndroidRuntime(11052):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:562)
11-04 11:59:14.137: E/AndroidRuntime(11052):    at dalvik.system.NativeStart.main(Native Method)
11-04 11:59:14.137: E/AndroidRuntime(11052): Caused by: android.os.NetworkOnMainThreadException
11-04 11:59:14.137: E/AndroidRuntime(11052):    at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1117)
11-04 11:59:14.137: E/AndroidRuntime(11052):    at java.net.InetAddress.lookupHostByName(InetAddress.java:385)
11-04 11:59:14.137: E/AndroidRuntime(11052):    at java.net.InetAddress.getAllByNameImpl(InetAddress.java:236)
11-04 11:59:14.137: E/AndroidRuntime(11052):    at java.net.InetAddress.getAllByName(InetAddress.java:214)
11-04 11:59:14.137: E/AndroidRuntime(11052):    at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:137)
11-04 11:59:14.137: E/AndroidRuntime(11052):    at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164)
11-04 11:59:14.137: E/AndroidRuntime(11052):    at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119)
11-04 11:59:14.137: E/AndroidRuntime(11052):    at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:360)
11-04 11:59:14.137: E/AndroidRuntime(11052):    at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:555)
11-04 11:59:14.137: E/AndroidRuntime(11052):    at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:653)
11-04 11:59:14.137: E/AndroidRuntime(11052):    at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:627)
11-04 11:59:14.137: E/AndroidRuntime(11052):    at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:616)
11-04 11:59:14.137: E/AndroidRuntime(11052):    at com.test.testing.AndroidFragmentation.onCreate(AndroidFragmentation.java:36)
11-04 11:59:14.137: E/AndroidRuntime(11052):    at android.app.Activity.performCreate(Activity.java:5104)
11-04 11:59:14.137: E/AndroidRuntime(11052):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
11-04 11:59:14.137: E/AndroidRuntime(11052):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2260)

private class HttpTask extends AsyncTask<String, Void, Void>{
    @Override
    protected Void doInBackground(String... params) {
        String url = params[0];
        DefaultHttpClient httpClient = new DefaultHttpClient();
        HttpGet httpGet = new HttpGet(url);
        ResponseHandler<String> resHandler = new BasicResponseHandler();
        try {
            String page = httpClient.execute(httpGet, resHandler);
        } catch (ClientProtocolException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return null;
    }

    @Override
    protected void onPostExecute(Void result) {
        super.onPostExecute(result);
        Toast.makeText(getApplicationContext(), "SUCCESS", 2000).show();
    }
}

HttpTask task = new HttpTask();
task.execute(url);