SWIFT -delegate

版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/yyyyccll/article/details/90292154

参考：https://www.cnblogs.com/jige/p/swift_delegate.html

//
//  SecondVC.swift
//

import UIKit

//
protocol PassTextDelegate:class {
    func passTex(textString : String?)
}

class SecondVC: UIViewController {

    var text = UITextField()
    //
    weak var PassTextDelegate : PassTextDelegate?
    
    override func viewDidLoad() {
        super.viewDidLoad()
        title = "vc2"
        view.backgroundColor = .white
        // 输入数据，传给上个页面
        text = UITextField(frame: CGRect(x: 100, y: 200, width: 100, height: 30))
        text.backgroundColor = .gray
        view.addSubview(text)
        
        let button = UIButton(frame: CGRect(x: 100, y: 100, width: 50, height: 30))
        button.setTitle("button", for: .normal)
        button.addTarget(self, action: #selector(popAction), for: .touchUpInside)
        button.backgroundColor = .gray
        view.addSubview(button)

    }
    //
    @objc func popAction() {
        PassTextDelegate?.passTex(textString: text.text)
        self.navigationController?.popViewController(animated: true)
    }
    
    

}

//
//  ViewController.swift
//
//

import UIKit

class ViewController: UIViewController {

    var label = UILabel()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        title = "vc1"
        let button = UIButton(frame: CGRect(x: 100, y: 100, width: 50, height: 30))
        button.setTitle("button", for: .normal)
        button.addTarget(self, action: #selector(nextPageAction), for: .touchUpInside)
        view.addSubview(button)
        button.backgroundColor = .gray
        
        // 接受数据的label
        label = UILabel(frame: CGRect(x: 100, y: 200, width: 100, height: 30))
        view.addSubview(label)
        label.backgroundColor = .gray
        
    }

    @objc func nextPageAction() {
        let second = SecondVC()
        //
        second.PassTextDelegate = self
        self.navigationController?.pushViewController(second, animated: true)
    }
}

//
extension ViewController : PassTextDelegate {
    func passTex(textString: String?) {
        label.text = textString
    }
    
    
    
}