I'm doing easy chat for android. I'm using this tutorial to do so. I have simple android client and java client.
I'm starting in few steps:
- Start server || message server: "Waiting client to connect"
- Start client || no message in server
- Click button || message server: "Client connected" and "Message from client: Connected" and "Server has ended."
- Android client crash with NetworkOnMainThreadException
Message of step 3 will appear onCreate client, so when I start app. When I click button it should send message to server. It crash with this error:
01-10 10:31:26.892 27458-27458/com.example.rachel.testapp E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.rachel.testapp, PID: 27458
java.lang.IllegalStateException: Could not execute method for android:onClick
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:293)
at android.view.View.performClick(View.java:5637)
at android.view.View$PerformClick.run(View.java:22429)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6119)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Method.invoke(Native Method)
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288)
at android.view.View.performClick(View.java:5637)
at android.view.View$PerformClick.run(View.java:22429)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6119)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)
Caused by: android.os.NetworkOnMainThreadException
at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1303)
at java.net.SocketOutputStream.socketWrite(SocketOutputStream.java:111)
at java.net.SocketOutputStream.write(SocketOutputStream.java:157)
at sun.nio.cs.StreamEncoder.writeBytes(StreamEncoder.java:221)
at sun.nio.cs.StreamEncoder.implFlushBuffer(StreamEncoder.java:291)
at sun.nio.cs.StreamEncoder.implFlush(StreamEncoder.java:295)
at sun.nio.cs.StreamEncoder.flush(StreamEncoder.java:141)
at java.io.OutputStreamWriter.flush(OutputStreamWriter.java:229)
at java.io.BufferedWriter.flush(BufferedWriter.java:254)
at com.example.rachel.testapp.MainActivity.sendMessage(MainActivity.java:88)
at java.lang.reflect.Method.invoke(Native Method)
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288)
at android.view.View.performClick(View.java:5637)
at android.view.View$PerformClick.run(View.java:22429)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6119)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)
I have android app like so
public class MainActivity extends AppCompatActivity
{
private static final String hostname = "localhost";
private static final int portnumber = 60125;
private static final String debugString = "debug";
private Socket socket = null;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
new Thread()
{
@Override
public void run()
{
try
{
Log.i(debugString, "Attempting to connect to server");
socket = new Socket(hostname, portnumber);
Log.i(debugString, "Connection established");
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()));
bw.write("Connected");
bw.newLine();
bw.flush();
BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream()));
System.out.println("Message from server:" + br.readLine());
} catch (IOException e)
{
Log.e(debugString, e.getMessage());
//e.printStackTrace();
}
}
}.start();
}
public void sendMessage(View view)
{
Toast.makeText(getApplicationContext(), "Klik", Toast.LENGTH_LONG).show();
EditText editText = (EditText) findViewById(R.id.editText);
BufferedWriter bw =null;
try
{
bw = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()));
bw.write(editText.getText().toString());
bw.newLine();
bw.flush();
}
catch (IOException e)
{
Log.e(debugString, e.getMessage());
}
}
}
And java server
public class main
{
private static final int portnumber = 60125;
public static void main(String[] args)
{
ServerSocket serverSocket = null;
try
{
System.out.println("Serwer port: "+ portnumber);
serverSocket = new ServerSocket(portnumber);
System.out.println("Waiting to connect");
Socket socket = serverSocket.accept();
System.out.println("Client connected");
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()));
bw.write("Message from server");
bw.newLine();
bw.flush();
BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream()));
String data;
while((data = br.readLine()) != null)
System.out.println("Message from client:"+data);
System.out.println("Server has ended.");
}
catch(IOException e)
{
e.printStackTrace();
}
}
}
