如何將自我設置為代表？

Question

當用戶在ViewController1中按下按鈕時，我希望它在ViewController2中調用一個函數。 我認為我唯一缺少的是將ViewController2分配為其自己的委托，但是如何將self聲明為委托？

ViewController1

protocol VC1Delegate {
    func pushThisButton(_ sender: UIButton)
}

class ViewController1: UIViewController {

    var delegate: VC1Delegate!
    var theButton = UIButton()

    override func viewDidLoad() {
        super.viewDidLoad()

        buildButton()

    }

    func pushButton(_ sender: UIButton) {
        delegate.pushThisButton(theButton)
    }

    func buildButton() {
        theButton = UIButton(frame: CGRect(x: 100, y: 100, width: 200, height: 50))
        theButton.backgroundColor = UIColor.black
        theButton.addTarget(self, action: #selector(pushButton), for: .touchUpInside)
        self.view.addSubview(theButton)
    }

}

視圖控制器2

class ViewController2: UIViewController, VC1Delegate {

    // I'm guessing somewhere here I need to declare myself as the delegate?

    override func viewDidLoad() {
        super.viewDidLoad()

    }

    func pushThisButton(_ sender: UIButton) {
        print("Damnit, Jack! Push the damn button!")
    }

}

Answer 1

實例化VC2時，應為其分配委托。 例如：

 protocol VC1Delegate: class {
     func pushThisButton(_ sender: UIButton)
 }

 class ViewController1: UIViewController {

     weak var delegate: VC1Delegate?

...

let vc2 = ViewController2() 
self.delegate = vc2 // we are in the VC1 context 
self.navigationController.pushViewController(vc2, animated: true)