UITabBarControllerをカスタムしてUITabBarItemを動的に変化させたり移動させたりします。
（実際はUITabBarItemではなくUIButtonです）
ソース
CustomTabbarController.swift
class CustomTabbarController: UITabBarController, UITabBarControllerDelegate
{
internal var vBase: UIView!
private var btnLeft: UIButton!
private var btnMid: UIButton!
private var btnRight: UIButton!
override func viewDidLoad()
{
super.viewDidLoad()
let V1 = Vc1() // UIViewController
let V2 = Vc2() // UIViewController
let V3 = Vc3() // UIViewController
viewControllers = [V1, V2, V3]
setupButtons()
selectedIndex = 1
tabBar.isHidden = true
}
func animateToTab(toIndex: Int)
{
if let vcTabs:[UIViewController] = viewControllers,
let vcSelected = selectedViewController,
let fromInx = vcTabs.index(of: vcSelected)
{
guard fromInx != toIndex else {return}
view.isUserInteractionEnabled = false
selectedIndex = toIndex
let orgSize = CGAffineTransform(scaleX: 1, y: 1)
let tapSize = CGAffineTransform(scaleX: 1.5, y: 1.5)
UIView.animate(withDuration: 0.1, animations: {
switch toIndex {
case 0:
self.btnLeft?.transform = tapSize
self.btnMid?.transform = orgSize
self.btnRight?.transform = orgSize
case 1:
self.btnLeft?.transform = orgSize
self.btnMid?.transform = tapSize
self.btnRight?.transform = orgSize
case 2:
self.btnLeft?.transform = orgSize
self.btnMid?.transform = orgSize
self.btnRight?.transform = tapSize
default:
break
}
}, completion: { finished in
self.view.isUserInteractionEnabled = true
})
}
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
func tapLeft(sender:AnyObject){
let toIndex = 0
animateToTab(toIndex: toIndex)
}
func tapMiddle(sender:AnyObject){
let toIndex = 1
animateToTab(toIndex: toIndex)
}
func tapRight(sender:AnyObject){
let toIndex = 2
animateToTab(toIndex: toIndex)
}
internal func setupButtons()
{
let scWidth = view.bounds.size.width
let scHeight = view.bounds.size.height
let hv = 60 as CGFloat
vBase = UIView()
vBase.frame = CGRect(x: 0, y: scHeight - hv, width: scWidth, height: hv)
self.view.addSubview(vBase)
btnLeft = UIButton()
btnLeft.frame = CGRect(x: 0, y: 0, width: hv, height: hv)
btnLeft.center = CGPoint(x: scWidth / 6, y: hv / 2)
btnLeft.backgroundColor = UIColor.yellow
btnLeft.addTarget(self, action: #selector(CustomTabbarController.tapLeft), for: UIControlEvents.touchUpInside)
vBase.addSubview(btnLeft)
btnMid = UIButton()
btnMid.frame = CGRect(x: 0, y: 0, width: hv, height: hv)
btnMid.center = CGPoint(x: scWidth / 2, y: hv / 2)
btnMid.transform = CGAffineTransform(scaleX: 1.25, y: 1.25)
btnMid.backgroundColor = UIColor.yellow
btnMid.addTarget(self, action: #selector(CustomTabbarController.tapMiddle), for: UIControlEvents.touchUpInside)
vBase.addSubview(btnMid)
btnRight = UIButton()
btnRight.frame = CGRect(x: 0, y: 0, width: hv, height: hv)
btnRight.center = CGPoint(x: scWidth / 6 * 5, y: hv / 2)
btnRight.backgroundColor = UIColor.yellow
btnRight.addTarget(self, action: #selector(CustomTabbarController.tapRight), for: UIControlEvents.touchUpInside)
vBase.addSubview(btnRight)
}
}