Here is how to animate Tab bar tab switch with a CrossDissolve slide transition in UITabBarViewController!

While searching for answer on web for how to give CurlUp / CrossDissolve / FlipFromRight / FlipFromLeft / CurlDown / FlipFromTop / FlipFromBottom transition effect for UITabBar Tab Switch.

 
I found out this answer but with bug or black screen when you tap on same tab twice i.e. destination and current tab is same.

 
So I solve this issue with my logic and additional if and else statement.

 
So here is final answer without any bug.

 

Step 01: Add this two classes as Super Class to your UITabBarViewController

 

UITabBarController, UITabBarControllerDelegate

 

Step 02: Now add following code to your viewDidLoad Function in your UITabBarViewController

 

self.delegate = self

 
So your viewDidLoad function will look something like this:

 

override func viewDidLoad() {
super.viewDidLoad()

// Do any additional setup after loading the view.

self.delegate = self;
}

 

Step 03: Now add following function to your UITabBarViewController file.

 

func tabBarController(_ tabBarController: UITabBarController, shouldSelect viewController: UIViewController) -> Bool {
let fromView = selectedViewController?.view
let toView = viewController.view

if fromView !== toView {
    UIView.transition(from: fromView!, to: toView!, duration: 0.5, options: [.transitionCrossDissolve], completion: nil)
} else {
    
}

return true
}

 
Now hopefully if you have done everything right you should see Tab Bar transition on Tab Bar switch.

 
Hope it helps,

 
Thanks & Regards
Mandar Apte