单击按钮时，UIView自定义委托不会调用

Question

我有一个有一个按钮的视图控制器。当我单击该按钮时，我想将自定义视图（xib）作为子视图添加到视图控制器。在我的自定义视图（xib）中，我还有一个自定义委托和一个按钮。但是当我单击自定义视图（xib）中的按钮时，视图控制器中的委托方法永远不会被调用。

//View Controller
class BusinessMainViewController: UIViewController,BusinessSettingViewDelegate {
//MARK: - business setting view delegate
func businessSettingViewAction(settingView: BusinessSettingView, button: UIButton) {
    switch button.tag {
    case 100:
        break
    default:
        break
    }
    settingView.removeFromSuperview()
}

//MARK: - Button action

@IBAction func settingAction(_ sender: UIButton) {
    let settingView = BusinessSettingView.init(parentView: self.view)
    settingView.delegate = self
    settingView.showSetting()

} 
}

//自定义视图+ xib：

+ xib name : BusinessSettingView.xib
+ custom view class: BusinessSettingView.swift

protocol BusinessSettingViewDelegate {
func businessSettingViewAction (settingView : BusinessSettingView, button : UIButton)
}

class BusinessSettingView: UIView {

var parentView : UIView!
var delegate : BusinessSettingViewDelegate?

override init(frame: CGRect) {
    super.init(frame: frame)
}

required init?(coder aDecoder: NSCoder) {
    super.init(coder: aDecoder)
}

convenience init(parentView : UIView) {
    self.init(frame: parentView.frame)

    let view : UIView = Bundle.main.loadNibNamed("BusinessSettingView", owner: self, options: nil)!.first as! UIView
    view.frame = self.frame
    view.alpha = 1
    self.addSubview(view)

    self.parentView = parentView
}

func showSetting() {
    DispatchQueue.main.async {
        self.parentView.addSubview(self)
    }
}

//MARK: - button action

@IBAction func historyAction(_ sender: UIButton) {
    if self.delegate != nil {
        self.delegate?.businessSettingViewAction(settingView: self, button: sender)
    }
}
}


// self.delegate is always nil