Android 不幸的是，Msger已经停止了。致命异常：主

可能重复：

当我尝试在第一个活动上从侦听器运行第二个活动时，main.xml有一个致命的异常。当我取出runTcpClient时；在TcpClient线程上，它可以正常加载

我遇到使用aSyncTask管理UI线程：

TcpClientJava.java的代码

}

LOGCAT

您正试图在主线程上执行可能较慢的网络操作，这在Android 3.0+中成为一个致命的异常。只需使用AsyncTask或Loader将runTcpClient移动到新线程

下面是一个例子：

试试这个：

class TcpClientTask extends AsyncTask<Void, Void, Void> {
    private static final int TCP_SERVER_PORT = 1234;
    private boolean error = false;

    protected Void doInBackground(Void... arg0) {
        try {
            Socket s = new Socket("10.0.2.2", TCP_SERVER_PORT);
            BufferedReader in = new BufferedReader(new InputStreamReader(s.getInputStream()));
            BufferedWriter out = new BufferedWriter(new OutputStreamWriter(s.getOutputStream()));
            //send output msg
            String outMsg = "TCP connecting to " + TCP_SERVER_PORT + System.getProperty("line.separator"); 
            out.write(outMsg);
            out.flush();
            Log.i("TcpClient", "sent: " + outMsg);
            //accept server response
            String inMsg = in.readLine() + System.getProperty("line.separator");
            Log.i("TcpClient", "received: " + inMsg);
            //close connection
            s.close();
        } catch (UnknownHostException e) {
            error = true;
            e.printStackTrace();
        } catch (IOException e) {
            error = true;
            e.printStackTrace();
        }
        return null;
    }

    protected void onPostExecute() {
        if(error) {
            // Something bad happened
        }
        else {
            // Success
        }

    }
}

---

StringBuilder在将字符串添加到一起时会产生较少的开销，只需在需要获取整个消息时使用msg.toString即可。

您不应该从主线程接触网络。 为网络操作实现异步任务

   private class MyInnerClass extends AsyncTask<String, Void, String> {
       @Override
       protected void onPreExecute() {
       super.onPreExecute();

       }

       @Override
       protected String doInBackground(String params) {

       return "Done";
       }

       @Override
       protected void onPostExecute(String result) {
       super.onPostExecute(result);
       }
   }

调用新的MyInnerClass.execute；从您的主要活动和android将自动调用onPreExecute，在您的网络访问之前，在该方法中执行您想执行的任何操作

Android随后将调用doInBackground

---

您是否在doInBackground中创建了与网络相关的内容，完成后将自动调用onPostExecute，结果将作为参数传递给此方法

试着使用一小段代码。但这不是好的做法

    StrictMode.setThreadPolicy(new StrictMode.ThreadPolicy.Builder()
   .detectNetwork()
   .permitNetwork() //permit Network access 
   .build());

您可以使用AsynTask或任何线程概念。

---

我看到了那篇文章，我试着按照他们的建议去做，但没有成功？我对Android还是个新手，我该如何在代码中实现aSyncTask呢？我也应该把所有的活动都改成那样吗？下班后我会试试，让你知道。终于让这项工作开始了，真是太激动了！山姆，你太棒了！我还没有测试过这个。因此，如果它不起作用，请让我知道，我将自己实现并修复它。当我使用此代码时，我得到描述资源路径位置类型TcpClient.TcpClientTask类型必须实现继承的抽象方法AsyncTask.doInBackgroundVoid…TcpClient.java/mesger/src/com/mesger line 32 java ProblemUse protected Void doInBackgroundVoid。。。arg0{并将returnnull；添加到doInBackground的末尾。嘿，山姆。可以在这里使用你的巧妙方法>>

class TcpClientTask extends AsyncTask<Void, Void, Void> {
    private static final int TCP_SERVER_PORT = 1234;
    private boolean error = false;

    protected Void doInBackground(Void... arg0) {
        try {
            Socket s = new Socket("10.0.2.2", TCP_SERVER_PORT);
            BufferedReader in = new BufferedReader(new InputStreamReader(s.getInputStream()));
            BufferedWriter out = new BufferedWriter(new OutputStreamWriter(s.getOutputStream()));
            //send output msg
            String outMsg = "TCP connecting to " + TCP_SERVER_PORT + System.getProperty("line.separator"); 
            out.write(outMsg);
            out.flush();
            Log.i("TcpClient", "sent: " + outMsg);
            //accept server response
            String inMsg = in.readLine() + System.getProperty("line.separator");
            Log.i("TcpClient", "received: " + inMsg);
            //close connection
            s.close();
        } catch (UnknownHostException e) {
            error = true;
            e.printStackTrace();
        } catch (IOException e) {
            error = true;
            e.printStackTrace();
        }
        return null;
    }

    protected void onPostExecute() {
        if(error) {
            // Something bad happened
        }
        else {
            // Success
        }

    }
}

StringBuilder msg = new StringBuilder();
String line;
while((line = in.readLine()) != null) // Keep reading until the end of the file is reached
    msg.append(in.readLine()).append(System.getProperty("line.separator"));

   private class MyInnerClass extends AsyncTask<String, Void, String> {
       @Override
       protected void onPreExecute() {
       super.onPreExecute();

       }

       @Override
       protected String doInBackground(String params) {

       return "Done";
       }

       @Override
       protected void onPostExecute(String result) {
       super.onPostExecute(result);
       }
   }

    StrictMode.setThreadPolicy(new StrictMode.ThreadPolicy.Builder()
   .detectNetwork()
   .permitNetwork() //permit Network access 
   .build());