title: TextViews not update in android UI
body: <p>we have two activities one is where we make the connection via bluetooth and managing the blutooth other one is the update the UI where we want to update the GUI containing the TextViews.
  We successfully send and recieve the message within two activities and vice versa.</p>
  
  <pre><code>private OnMessageReceivedListener dataReceivedListener = new OnMessageReceivedListener() {
      public void OnMessageReceived(String device, String message) {
          //t.setText(message);
          Log.d("Message" , message);
          msg = message;
          UpdateGUI();
  
      }
  };
  </code></pre>
  
  <p>THE above function recieves the message and we did that successfully.</p>
  
  <pre><code> private void UpdateGUI() {
      //i++;
      //tv.setText(String.valueOf(i));
      myHandler.post(myRunnable);
   }
  
   final Runnable myRunnable = new Runnable() {
      public void run() {  
      btBoard.UpdateYoursBoard(mystring);
  
      }
   };
  </code></pre>
  
  <p>The above function of connection class calls the method of our GUI class and send a recieved message to it.</p>
  
  <p>In our GUI class we want this</p>
  
  <pre><code>    public void UpdateYoursBoard(String positions)
  {
      Log.d("Positions" , positions);
      tv.setText(positions);
  </code></pre>
  
  <p>};
  we successfully recieved the message in log.d but when we want to change our textview text it gives following errors.</p>
  
  <pre><code>       java.lang.NullPointerException
         at net.clc.bt.Board.UpdateYoursBoard(Board.java:3460) 
  </code></pre>
  
  <p><strong>NOTE</strong> : we are working with bluetooth and we have 3 mobile connected simultaneously and UpdateYourBoard will change the TextViews of 3 mobiles GUI's.</p>
  
  <p>kindly help me to fix the problem.
  Thanks in advance</p>