Swift-属性传值,闭包传值,代理传值

AppDelegate.swift代码如下：

import UIKit

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?


    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
        self.window = UIWindow(frame:UIScreen.main.bounds)
        self.window?.backgroundColor = #colorLiteral(red: 0.4745098054, green: 0.8392156959, blue: 0.9764705896, alpha: 1)
        self.window?.makeKeyAndVisible()
        //1.创建导航控制器的根视图
        let rootVC = ViewController()
        //2.创建导航视图控制器，并为他制定根视图控制器
        let navigation = UINavigationController(rootViewController: rootVC)
        //3.将导航视图控制器设置为window的根视图控制器
        self.window?.rootViewController = navigation
        return true
    }

ViewController.swift代码如下：

import UIKit
//代理传值第四步:
class ViewController: UIViewController,SecondViewControllerDeleget {

    var lable:UILabel!
    var textField:UITextField!

    override func viewDidLoad() {
        super.viewDidLoad()
        self.setupViews()
        self.view.backgroundColor = #colorLiteral(red: 0.9098039269, green: 0.4784313738, blue: 0.6431372762, alpha: 1)
        self.title = "首页"
    }
    func setupViews(){
        self.lable  = UILabel(frame: CGRect(x: 107, y: 150, width: 200, height: 40))
        self.lable.backgroundColor = #colorLiteral(red: 0.9764705896, green: 0.850980401, blue: 0.5490196347, alpha: 1)
        self.view.addSubview(lable)

        self.textField = UITextField(frame: CGRect(x: 107, y: 220, width: 200, height: 40))
        self.textField.backgroundColor = #colorLiteral(red: 0.721568644, green: 0.8862745166, blue: 0.5921568871, alpha: 1)
        self.view.addSubview(textField)

        let button = UIButton(frame: CGRect(x: 107, y: 280, width: 200, height: 40))
        button.backgroundColor = #colorLiteral(red: 0.8039215803, green: 0.8039215803, blue: 0.8039215803, alpha: 1)
        button.setTitle("跳转", for: .normal)
        self.view.addSubview(button)

        button.addTarget(self, action: #selector(buttonAction), for: .touchUpInside)

    }
    //MARK:- button关联事件
    func buttonAction(sender:UIButton) {
        let secondVC = SecoundViewController()
        //属性赋值第二步:
        secondVC.content = self.textField.text
        //闭包传值第二步:
        secondVC.passValue = {
            (text:String) in
            //取出参数值，为前一个界面的控件赋值
            self.lable.text = text
        }
        //代理传值第三步
        secondVC.delegate = self
        self.navigationController?.pushViewController(secondVC, animated: true)

    }
    //代理传值第五步
    func sendValue(text: String) {
    self.lable.text = text
    }
    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
}

SecoundViewController.swift代码如下：

/*
 从前往后传值
 属性传值一共分为三步:
 1.定义一个要与传值数据类型相同的属性
 2.给属性赋值
 3.取出属性中的值
 
 从后往前传值
 闭包传值:
 1.定义一个闭包属性
 2.在前一个界面为闭包属性赋值
 3.在pop回去之前调用闭包
 
 代理传值
 1.定义协议
 2.定义代理属性
 3.代理对象所在类遵循协议
 4.代理对象所在类遵循协议
 5.代理对象所在类实现协议中的方法
 6.通知代理对象干活
 */

import UIKit
//代理传值第一步:
protocol SecondViewControllerDeleget {
    func sendValue(text:String)
}
class SecoundViewController: UIViewController {

    var lable:UILabel!
    var textField:UITextField!
    //属性传值第一步
    var content:String!
    //闭包传值第一步:
    var passValue:((String)->())!
    //代理传值第二步:
    var delegate:SecondViewControllerDeleget!


    override func viewDidLoad() {
        super.viewDidLoad()
        self.setupViews()
        //属性传值第三步:
        self.lable.text = self.content


        self.view.backgroundColor = #colorLiteral(red: 0.4745098054, green: 0.8392156959, blue: 0.9764705896, alpha: 1)
        
        
    }
    func setupViews(){
        self.lable  = UILabel(frame: CGRect(x: 107, y: 150, width: 200, height: 40))
        self.lable.backgroundColor = #colorLiteral(red: 0.9764705896, green: 0.850980401, blue: 0.5490196347, alpha: 1)
        self.view.addSubview(lable)

        self.textField = UITextField(frame: CGRect(x: 107, y: 220, width: 200, height: 40))
        self.textField.backgroundColor = #colorLiteral(red: 0.721568644, green: 0.8862745166, blue: 0.5921568871, alpha: 1)
        self.view.addSubview(textField)

        let button = UIButton(frame: CGRect(x: 107, y: 280, width: 200, height: 40))
        button.backgroundColor = #colorLiteral(red: 0.8039215803, green: 0.8039215803, blue: 0.8039215803, alpha: 1)
        button.setTitle("返回", for: .normal)
        self.view.addSubview(button)

        button.addTarget(self, action: #selector(buttonAction), for: .touchUpInside)

    }
    //MARK:- button关联事件
    func buttonAction(sender:UIButton) {
        //闭包传值第三步:
//        self.passValue(self.textField.text!)
        //代理传值第六步
        self.delegate.sendValue(text: self.textField.text!)
        
        self.navigationController?.popViewController(animated: true)


    }

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

    /*
    // MARK: - Navigation

    // In a storyboard-based application, you will often want to do a little preparation before navigation
    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        // Get the new view controller using segue.destinationViewController.
        // Pass the selected object to the new view controller.
    }
    */

}