gcm_id.java

new Thread(new Runnable() {
          @Override
          public void run() {
              try {
                  InstanceID instanceID = InstanceID.getInstance(getApplicationContext());
                  final String token = instanceID.getToken(getApplicationContext().getString(com.asus.robotrtcsdk.R.string.gcm_defaultSenderId),
                          GoogleCloudMessaging.INSTANCE_ID_SCOPE, null);
                  runOnUiThread(new Runnable() {
                      @Override
                      public void run() {
                          Toast.makeText(getApplicationContext(), token, Toast.LENGTH_LONG).show();
                      }
                  });
              } catch (IOException e) {
                  e.printStackTrace();
              }
          }
      }).start();