Android TCP Client TextView doesn't Update

Question

I'm trying to come up with an android client app that talks with a C#server. I want to update my TextView simultaneously with the server reply message. I'm receiving message with this code

public class LogedInActivity extends ActionBarActivity  {
private Spinner meterBrands;
private EditText sayacNo,plcNo;
private String serverMessage="Message is";
private TextView serverStatus; 
private String messageID="120";
private String messageEnd="*?/";
private Thread clientThread;
private static final int SERVERPORT = sss;
private static final String SERVER_IP = "sss";

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_loged_in);
     serverStatus= (TextView) findViewById(R.id.serverStatus); 

    if (savedInstanceState == null) {
        getSupportFragmentManager().beginTransaction()
        .add(R.id.container, new PlaceholderFragment()).commit();
    }

} 
public void sendMessage(View view) {

     hideSoftKeyboard(this);
    meterBrands= (Spinner) findViewById(R.id.brandsSpinner);
    String temp=String.valueOf(meterBrands.getSelectedItem()); 
    if(isValidMeterAndPLC()){
        new Thread(new Runnable() {
            public void run() {
                connectSocket(messageToSend());

                }
            }).start();

    } else {
        new Thread(new Runnable() {
            public void run() {
                connectSocket("1");
                    }
            }).start();
    }


} 


private String connectSocket(String message){ 

String finalText = "";
try { 
    InetAddress serverAddr = InetAddress.getByName(SERVER_IP); 
    Log.d("TCP", "C: Connecting..."); 
    Socket socket = new Socket(serverAddr, SERVERPORT); 



    PrintWriter out = null;
    BufferedReader in = null;

    try { 
        Log.d("TCP", "C: Sending: '" + message + "'"); 
        out = new PrintWriter( new BufferedWriter( new      OutputStreamWriter(socket.getOutputStream())),true); 
        in = new BufferedReader(new InputStreamReader(socket.getInputStream()));                
        out.println(message);
        String text = "";
        while ((text = in.readLine()) != null) {
            finalText += text; 
            serverStatus.setText(finalText);
           }


        Log.d("TCP", "C: Sent."); 

        Log.d("TCP", "C: Done.");               

    } catch(Exception e) { 
        Log.e("TCP", "S: Error", e); 
    } finally { 
        socket.close(); 
    } 

} catch (UnknownHostException e) { 
    // TODO Auto-generated catch block 
    Log.e("TCP", "C: UnknownHostException", e); 
    e.printStackTrace(); 
} catch (IOException e) { 
    // TODO Auto-generated catch block 
    Log.e("TCP", "C: IOException", e); 
    e.printStackTrace(); 
}       
return finalText;
} 


public String messageToSend(){
    String infoString;
    sayacNo= (EditText) findViewById(R.id.sayacNoTextBox);
    plcNo= (EditText) findViewById(R.id.plcNoTextBox);

    infoString= messageID+"-"+sayacNo.getText()+"-"+meterBrands.getSelectedItem().toString()+"-"+plcNo.getText()+ "-" +messageEnd+"-" ;
    infoString+=checkSum(infoString);

    return infoString;

}
public int checkSum(String str){
    int checkSum=0;
    char [] strChars= str.toCharArray();
    for(int i=0;i<strChars.length;i++){
        checkSum+= (int) strChars[i];

    }


    return checkSum;
}
public void messageDisplay(String servermessage){
    serverStatus= (TextView) findViewById(R.id.serverStatus);
    serverStatus.setText(servermessage);

}  


private boolean isValidMeterAndPLC(){
    boolean check=true;
    int sayacNoInt=0;
    sayacNo=(EditText) findViewById(R.id.sayacNoTextBox);
    plcNo=(EditText) findViewById(R.id.plcNoTextBox);

    sayacNoInt=Integer.parseInt(sayacNo.getText().toString());
    if(sayacNoInt<100 || sayacNoInt>65530){
        alertbox("Yanlış Sayaç Numarası","Yanlış sayaç numarası girdiniz. Lütfen tekrar deneyin.");
        check=false;

    }
    if(plcNo.getText().toString().length()!=8){
        alertbox("Yanlış PLC Numarası","Yanlış PLC numarası girdiniz. Lütfen tekrar deneyin.");
        check=false;
    }
    return check;

}
protected void alertbox(String title, String mymessage)
{

    AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(
            this);

    // set title
    alertDialogBuilder.setTitle(title);

    // set dialog message
    alertDialogBuilder
    .setMessage(mymessage)
    .setCancelable(false)
    .setPositiveButton("Okay",new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog,int id) {
            // if this button is clicked, close
            // current activity

        }
    });

    // create alert dialog
    AlertDialog alertDialog = alertDialogBuilder.create();

    // show it
    alertDialog.show();
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();
    if (id == R.id.action_settings) {
        return true;
    }
    return super.onOptionsItemSelected(item);
}

/**
 * A placeholder fragment containing a simple view.
 */
public static class PlaceholderFragment extends Fragment {

    public PlaceholderFragment() {
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.fragment_loged_in,
                container, false);
        return rootView;
    }
}
@Override
public boolean onTouchEvent(MotionEvent event) {

    hideSoftKeyboard(this);

    return false;
}

/*back button override.
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
    if (keyCode == KeyEvent.KEYCODE_BACK) {
        alertbox("asasda","5333434");
        return true;
    }

    return super.onKeyDown(keyCode, event);
}
 */
public static void hideSoftKeyboard(Activity activity) {

    InputMethodManager inputMethodManager = (InputMethodManager)  activity.getSystemService(Activity.INPUT_METHOD_SERVICE);
    inputMethodManager.hideSoftInputFromWindow(activity.getCurrentFocus().getWindowToken(), 0);
}

}

However, I can't update my TextView since it's in a thread

      new Thread(new Runnable() {
            public void run() {
                connectSocket(messageToSend());

                    }
            }).start();

Answer 1

Simply wrap the sentence where you update with the runOnUiThread() statement. For instance:

your_context.runOnUiThread(new Runnable() {
  public void run() {
    myTextView.setText("...");
  }
});

Anything wrapped in the runOnUiThread() statement will actually be run in the main UI Thread, so be careful to not add some expensive operations here.

---- EDIT ----

new Thread(new Runnable() {
  public void run() {
    connectSocket(messageToSend());

    // Do whatever you need
    ...

    // Once you want to update your TextView...
    final myTextView tv = (TextView) your_context.findViewById(R.id.myTextView);
    final String myText = "whatever";

    your_context.runOnUiThread(new Runnable() {
      public void run() {
        myTextView.setText(myText);
      }
    });
  }
}).start();