說明

原本想直接用ＡＩ但發現結果錯誤百出且點作用都沒有，所以再加上一些設定。

程式

增加protocol及部分宣告
Btn:

    var delegate:  btnViewDelegate?
 var delegate:  btnViewDelegate?
    var stringTag: Int?
    
    var buttonTapped: ((Int) -> ())? = nil
    
protocol btnViewDelegate : AnyObject {
    func didTapButton(tag: Int)
}

tarbar:

 var buttonTappen: ((Int) -> ())? = nil
    let item = BottomItems.allCases
    
extension tarbarViewController: btnViewDelegate {
    func didTapButton(tag: Int) {
        buttonTappen?(item[tag].rawValue)
        print("Button tapped with tag: \(tag)")
    }
}

Main:

 private var onev = oneViewController()
        private var twov = twoViewController()
        private var threev = threeViewController()
        var vc: [UIViewController] = []
        var nowVC: Int = BottomItems.oneViewController.rawValue