Question

I have not done much animation, and I need some help with this. I have a tabBarController as my root controller, and I want to have another tabBarController, and I want to bring it up as a Modal View Controller, and I have a problem with the animation.

There are currently four animations for modalViewControllers, namely

typedef enum {
UIModalTransitionStyleCoverVertical = 0,
UIModalTransitionStyleFlipHorizontal,
UIModalTransitionStyleCrossDissolve,
UIModalTransitionStylePartialCurl,
} UIModalTransitionStyle;

I want a different animation – slide from the right to the left. – How can I do this animation?

Any help with this?

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Edit:

My idea to push a tabBarController onto the navigation stack sucks! Apple’s comment on this approach:

You never want to push a tab bar controller onto the navigation stack of a navigation controller. Doing so creates an unusual situation whereby the
tab bar appears only while a specific view controller is at the top of the navigation stack. Tab bars are designed to be persistent, and so this transient approach can be confusing to users.

I am out of ideas. Someone help me with the animation for modal view controllers.

Answer 1

You could write the animation code manually. Here are the general steps:

• Create a subclass of UIViewController (essentially a dud controller to house your UITabBarController) – I usually call this ShellViewController.
• In the ShellViewController‘s init method (whichever one you would use), set its frame outside of the screen to the right, e.g. [self.view setFrame:CGRectMake(320, 0, 320, 480)];
• Create two methods within ShellViewController
  • - (void)presentSelf
  • - (void)dismissSelf
• Create an instance of ShellViewController when you want to present your UITabBarController
• Place your UITabBarController instance inside of the ShellViewController instance
• Call [currentView addSubview:shellViewController.view];
• Use the custom methods above to present and dismiss the ShellViewController housing your UITabBarController
• Deal with memory management as your business logic dictates

Here is the code for animating-in (e.g. the - (void)presentSelf method):

[UIView beginAnimations:nil context:nil];
[UIView setAnimationDuration:0.15]; //the double represents seconds
[UIView setAnimationDelegate:self];
[UIView setAnimationCurve:UIViewAnimationCurveEaseOut];
[[self view] setFrame:CGRectMake(0, 0, 320, 480)];
[UIView commitAnimations];

Here is the code for animating-out (e.g. the - (void)dismissSelf method):

[UIView beginAnimations:nil context:nil];
[UIView setAnimationDuration:0.15];
[UIView setAnimationDelegate:self];
[UIView setAnimationCurve:UIViewAnimationCurveEaseOut];
[[self view] setFrame:CGRectMake(320, 0, 320, 480)];
[UIView commitAnimations];

Keep in mind that these animation methods do only that: animate. They don’t disable interaction with the current view nor with the ShellViewController‘s view/subviews which are being animated in/out. You’ll need to manually disable user interaction during animation and then reinstate it after the animation is finished. There is a UIView method that performs a selector when animation is finished:

[UIView setAnimationDidStopSelector:@selector(enableUserInteraction)];

You can put this right after the [UIView setAnimationDelegate:self] in each animation block above. Of course, you would need to write the enableUserInteraction method yourself… and disableUserInteraction method for that matter.

It is a hassle to go this route, but it works. Once you get the ShellViewController written up, it makes for a nice reusable snippet.