public void onBackPressed() {
   if (startedTracking || checkTransitionAnimation() || fragmentsStack.isEmpty()) {
     return;
   }
   if (currentActionBar != null && currentActionBar.isSearchFieldVisible) {
     currentActionBar.closeSearchField();
     return;
   }
   BaseFragment lastFragment = fragmentsStack.get(fragmentsStack.size() - 1);
   if (lastFragment.onBackPressed()) {
     if (!fragmentsStack.isEmpty()) {
       closeLastFragment(true);
     }
   }
 }