switchRootViewController

switchRootViewController

- (void)switchRootViewController:(UIViewController *)viewController
                        animated:(BOOL)animated
                      completion:(void (^)())completion
{
    UIWindow *window = self.appDelegate.window;

    if (animated) {
        [UIView transitionWithView:window
                          duration:0.3
                           options:UIViewAnimationOptionTransitionCrossDissolve
                        animations:^
         {
             BOOL oldState = [UIView areAnimationsEnabled];
             [UIView setAnimationsEnabled:NO];
             window.rootViewController = viewController;
             [UIView setAnimationsEnabled:oldState];
         } completion:^(BOOL finished) {
             if (completion) completion();
         }];
    } else {
        window.rootViewController = viewController;
        if (completion) completion();
    }
}