title: Show alert in present activity by other device using a Bluetooth chat example
body: <p>I am developing a Bluetooth chat application with the help of the Bluetooth chat application on the Android developer site.</p>
  
  <p>I did some modifications in existing code as when I send Bluetooth chat requests to another device (assume we are paired previously) and request receiving device resides in any activity.</p>
  
  <p>I want to display an alert to the current displaying screen, but I am getting an alert at a particular activity only. So I am getting stuck. My code is below for the sender and receiver side:</p>
  
  <pre><code>if (FaceCardList.requestConnection &amp;&amp;
      FaceCardList.deviceSelected) {
  
      String authorization = "messagetype:startChat,"
                              + FaceCardList.ScreenName;
      FaceCardList.this.sendMessage(authorization);
  }
  </code></pre>
  
  <p>On the receiving side:</p>
  
  <pre><code>if (readMessage.indexOf("messagetype:startChat") != -1) {
  
      AlertDialog.Builder builder =
          new AlertDialog.Builder(FaceCardList.this);
      builder.setMessage(
          FaceCardList.screennmname + " wants to chat with you")
          .setCancelable(false)
          .setPositiveButton("Yes",
              new DialogInterface.OnClickListener() {
  
                  public void onClick(DialogInterface arg0, int arg1) {
                      Intent serverIntent = new Intent(
                              FaceCardList.this,
                              BluetoothChat.class);
                      startActivity(serverIntent);
  
                      String authorization = "messagetype:initiatechat";
                      FaceCardList.this
                              .sendMessage(authorization);
                  }
              })
          .setNegativeButton("No",
              new DialogInterface.OnClickListener() {
  
                  public void onClick(
                          DialogInterface diaLog,
                          int which) {
                      // TODO Auto-generated method stub
  
                      String authorization = "messagetype:stopservice";
                      FaceCardList.this
                              .sendMessage(authorization);
  
                      FaceCardList.mChatService.stop();
                      FaceCardList.mChatService.start();
                  }
              });
      alert = builder.create();
      alert.show();
  </code></pre>