iOS Swift – 如何以编程方式为所有按钮指定默认操作

那么你想要实现的目标是什么.我已经使用UIViewController扩展并添加了一个闭包作为没有目标的按钮的目标.如果按钮没有动作,则会显示警报.

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        self.checkButtonAction()
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)

    }
    @IBACtion func btn_Action(_ sender: UIButton) {

    }

}

extension UIViewController{
    func checkButtonAction(){
        for view in self.view.subviews as [UIView] {
            if let btn = view as? UIButton {
                if (btn.allTargets.isEmpty){
                    btn.add(for: .touchUpInside,{
                        let alert = UIAlertController(title: "Test 3",message:"No SELEctor",preferredStyle: UIAlertControllerStyle.alert)

                        // add an action (button)
                        alert.addAction(UIAlertAction(title: "OK",style: UIAlertActionStyle.default,handler: nil))

                        // show the alert
                        self.present(alert,animated: true,completion: nil)
                    })
                }
            }
        }

    }
}
class ClosureSleeve {
    let closure: ()->()

    init (_ closure: @escaping ()->()) {
        self.closure = closure
    }

    @objc func invoke () {
        closure()
    }
}

extension UIControl {
    func add (for controlEvents: UIControlEvents,_ closure: @escaping ()->()) {
        let sleeve = ClosureSleeve(closurE)
        addTarget(sleeve,action: #SELEctor(ClosureSleeve.invokE),for: controlEvents)
        objc_setAssociatedObject(self,String(format: "[%d]",arc4random()),sleeve,objc_AssociationPolicy.oBJC_ASSOCIATION_RETAIN)
    }
}

我测试了它.希望这可以帮助.快乐的编码.