Navigation bar gets adjusted after calling completeTransition: in custom transition

Question

My goal is to provide zooming modal transition from for the user from a view similar as springboard icons zoom in when launching apps.

The presented view controller

Answer 1

The problem is that you are setting the transform before inserting the destination view controller's view into the container.

Switching the order should fix it:

if (self.reverse) {
    [container insertSubview:toViewController.view belowSubview:fromViewController.view];
} else {
    [container addSubview:toViewController.view];
    toViewController.view.transform = transform;
}

See point 4 here. Since you've applied a transform prior to inserting the navigation controller's view as a subview, the layout engine doesn't think the navigation bar is at the top edge of the window, and therefore doesn't need to be adjusted to avoid the status bar.

Answer 2

I've found a solution, although pretty hacky. I have to manually adjust the navigation bar frame before the animation starts:

if (self.reverse) {
    [container insertSubview:toViewController.view belowSubview:fromViewController.view];
} else {
    toViewController.view.transform = transform;
    [container addSubview:toViewController.view];

    // fix navigation bar position to prevent jump when completeTransition: is called
    if ([toViewController isKindOfClass:[UINavigationController class]]) {
        UINavigationController* navigationController = (UINavigationController*) toViewController;
        UINavigationBar* bar = navigationController.navigationBar;
        CGRect frame = bar.frame;
        bar.frame = CGRectMake(frame.origin.x, frame.origin.y + 20.0f, frame.size.width, frame.size.height);
    }
}

Answer 3

This is still a hack, based on Ondřej Mirtes' one but it works better if you have an in-call status bar and you're on iOS8

if([toViewController isKindOfClass:[UINavigationController class]]) { 
  UINavigationController *navCtrl = (UINavigationController *)toViewController;
  UINavigationBar *navBar = navCtrl.navigationBar;
  if(navBar.frame.origin.y == 0 && navBar.frame.size.height == 44) {
    navBar.frame = CGRectMake(0, 0, navBar.frame.size.width, fmin(44 + [UIApplication sharedApplication].statusBarFrame.size.height, 64)); 
  }
}

Remains ugly though :/

Answer 4

Add the toViewControllerView first to the ContainerView, then set the toViewControllerView transform as given below.

[container addSubview:toViewController.view];

toViewController.view.transform = transform;

This will solve the problem.