public static void popScreen() {
   DesignToolbar designToolbar = Ode.getInstance().getDesignToolbar();
   long projectId = Ode.getInstance().getCurrentYoungAndroidProjectId();
   String newScreen;
   if (pushedScreens.isEmpty()) {
     return; // Nothing to do really
   }
   newScreen = pushedScreens.removeFirst();
   designToolbar.doSwitchScreen(projectId, newScreen, View.BLOCKS);
 }
 /*
  * PushScreen -- Static method called by Blockly when the Companion requests
  * That we switch to a new screen. We keep track of the Screen we were on
  * and push that onto a stack of Screens which we pop when requested by the
  * Companion.
  */
 public static boolean pushScreen(String screenName) {
   DesignToolbar designToolbar = Ode.getInstance().getDesignToolbar();
   long projectId = Ode.getInstance().getCurrentYoungAndroidProjectId();
   String currentScreen = designToolbar.currentProject.currentScreen;
   if (!designToolbar.currentProject.screens.containsKey(
       screenName)) // No such screen -- can happen
   return false; // because screen is user entered here.
   pushedScreens.addFirst(currentScreen);
   designToolbar.doSwitchScreen(projectId, screenName, View.BLOCKS);
   return true;
 }
 /*
  * Switch to screen name in project projectId. Also switches projects if
  * necessary.
  */
 public void switchToScreen(long projectId, String screenName, View view) {
   doSwitchScreen(projectId, screenName, view);
 }