Question

After the program running，click the send button，then pop-up dialog said the program has already exited。

I don‘t know what is the problem，how can I fix it？
Is there anybody has the same issue，can you help me？

package com.secion9.clienttest;

import android.os.Bundle;
import android.app.Activity;
import android.widget.*;
import java.net.Socket;
import java.io.IOException;
import java.io.OutputStream;
import android.view.View;
import android.view.View.OnClickListener;
public class ClientActivity extends Activity {

Button btSend;
EditText etMsg;
  @Override
  public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_client);
  btSend=(Button)this.findViewById(R.id.button1);
  etMsg=(EditText)this.findViewById(R.id.EditText1);
  btSend.setOnClickListener(
  new OnClickListener(){
  public void onClick(View v)
  {
try
{

Socket socket=new Socket("127.0.0.1",5050);
OutputStream outputStream=socket.getOutputStream();
byte[] buffer=etMsg.getText().toString().getBytes();
outputStream.write(buffer);
outputStream.flush();

}
catch(IOException e)
{
e.printStackTrace();
}
  }
  });
  }
}

logcat

09-02 08:24:31.189: E/Trace(627): error opening trace file: No such file or directory (2)
09-02 08:24:32.259: D/gralloc_goldfish(627): Emulator without GPU emulation detected.
09-02 08:24:32.598: I/Choreographer(627): Skipped 40 frames! The application may be doing too much work on its main thread.
09-02 08:25:04.471: D/AndroidRuntime(627): Shutting down VM
09-02 08:25:04.471: W/dalvikvm(627): threadid=1: thread exiting with uncaught exception (group=0x40a13300)
09-02 08:25:04.539: E/AndroidRuntime(627): FATAL EXCEPTION: main
09-02 08:25:04.539: E/AndroidRuntime(627): android.os.NetworkOnMainThreadException
09-02 08:25:04.539: E/AndroidRuntime(627): at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1117)
09-02 08:25:04.539: E/AndroidRuntime(627): at libcore.io.BlockGuardOs.connect(BlockGuardOs.java:84)
09-02 08:25:04.539: E/AndroidRuntime(627): at libcore.io.IoBridge.connectErrno(IoBridge.java:127)
09-02 08:25:04.539: E/AndroidRuntime(627): at libcore.io.IoBridge.connect(IoBridge.java:112)
09-02 08:25:04.539: E/AndroidRuntime(627): at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:192)
09-02 08:25:04.539: E/AndroidRuntime(627): at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172)
09-02 08:25:04.539: E/AndroidRuntime(627): at java.net.Socket.startupSocket(Socket.java:566)
09-02 08:25:04.539: E/AndroidRuntime(627): at java.net.Socket.tryAllAddresses(Socket.java:127)
09-02 08:25:04.539: E/AndroidRuntime(627): at java.net.Socket.<init>(Socket.java:177)
09-02 08:25:04.539: E/AndroidRuntime(627): at java.net.Socket.<init>(Socket.java:149)
09-02 08:25:04.539: E/AndroidRuntime(627): at com.secion9.clienttest.ClientActivity$1.onClick(ClientActivity.java:31)
09-02 08:25:04.539: E/AndroidRuntime(627): at android.view.View.performClick(View.java:4084)
09-02 08:25:04.539: E/AndroidRuntime(627): at android.view.View$PerformClick.run(View.java:16966)
09-02 08:25:04.539: E/AndroidRuntime(627): at android.os.Handler.handleCallback(Handler.java:615)
09-02 08:25:04.539: E/AndroidRuntime(627): at android.os.Handler.dispatchMessage(Handler.java:92)
09-02 08:25:04.539: E/AndroidRuntime(627): at android.os.Looper.loop(Looper.java:137)
09-02 08:25:04.539: E/AndroidRuntime(627): at android.app.ActivityThread.main(ActivityThread.java:4745)
09-02 08:25:04.539: E/AndroidRuntime(627): at java.lang.reflect.Method.invokeNative(Native Method)
09-02 08:25:04.539: E/AndroidRuntime(627): at java.lang.reflect.Method.invoke(Method.java:511)
09-02 08:25:04.539: E/AndroidRuntime(627): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
09-02 08:25:04.539: E/AndroidRuntime(627): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
09-02 08:25:04.539: E/AndroidRuntime(627): at dalvik.system.NativeStart.main(Native Method)
09-02 08:25:07.079: I/Process(627): Sending signal. PID: 627 SIG: 9

Answer 1

It sounds like you’re doing networking on the main thread. That’s a no-no:

• http://developer.android.com/reference/android/os/NetworkOnMainThreadException.html

SOLUTION:

Modify your app so that it spawns off a thread or async task to do the network I/O.

Here’s a good link that discusses how:

• http://www.vogella.com/articles/AndroidPerformance/article.html