text#crollanimation#tabbar#tabbarcontroller

https://stackoverflow.com/questions/5161730/iphone-how-to-switch-tabs-with-an-animation
// DELEGATE
UICollectionViewController {
self.delegate = self
}
ViewController {
collectionView.delegate = self
}
// EXTENSION
extension TabBarViewController: UITabBarControllerDelegate {

public func tabBarController(_ tabBarController: UITabBarController, shouldSelect viewController: UIViewController) -> Bool {
if let nextVCIndex = tabBarController.viewControllers?.index(of: viewController) {
guard let fromView = tabBarController.selectedViewController?.view else {
return false
}

guard let toView = viewController.view else {
return false
}

if fromView == toView {
return false
}

let isCrollRight = selectedIndex
fromView.superview!.addSubview(toView)
let width = fromView.frame.width
let height = fromView.frame.height

toView.frame = CGRect(x: (isCrollRight ? width : -width), y: fromView.frame.origin.y, width: width, height: height)

UIView.animate(withDuration: 0.3, animations: {() -> Void in
fromView.frame.origin = CGPoint(x: (isCrollRight ? -width : width), y: fromView.frame.origin.y)
toView.frame.origin = CGPoint(x: 0, y: fromView.frame.origin.y)
}) {(finished) -> Void in
fromView.removeFromSuperview()

// Nếu kh&＃244;ng th&＃234;m line n&＃224;y app sẽ bị crash khi user change tab qu&＃225; nhanh v&＃224; nhiều lần li&＃234;n tiếp
self.selectedIndex = nextVCIndex
}
}
return true
}

}