fix(back button): do not animate back button transition if the title …

…doesn't change. Fixes #1858

js/angular/controller/navBarController.js

@@ -16,6 +16,10 @@ function($scope, $element, $attrs, $ionicViewService, $animate, $compile, $ionic
 
   $scope.$on('$destroy', deregisterInstance);
 
+  $scope.$on('$viewHistory.historyChange', function(e, data) {
+    backIsShown = !!data.showBack;
+  });
+
   var self = this;
 
   this.leftButtonsElement = jqLite(
@@ -60,6 +64,10 @@ function($scope, $element, $attrs, $ionicViewService, $animate, $compile, $ionic
 
   this.changeTitle = function(title, direction) {
     if ($scope.title === title) {
+      // if we're not animating the title, but the back button becomes invisible
+      if(typeof backIsShown != 'undefined' && !backIsShown && $scope.backButtonShown){
+        jqLite($element[0].querySelector('.back-button')).addClass('ng-hide');
+      }
       return false;
     }
     this.setTitle(title);