Swift中的7种界面传值方式总结(属性传值,构造器传值,通知传值,单例传值,协议传值,闭包传值,NSUserDefaults传值)

//第一个界面ViewController
import UIKit
class ViewController: UIViewController {
fileprivate var tf:UITextField = UITextField()
  override func viewDidLoad() {
    super.viewDidLoad()

    setUpUI()

  }
 //点击进入第二个界面的按钮进行跳转操作
 @objc fileprivate func btnAction()  {
    let vc = DetailViewController()
    navigationController?.pushViewController(vc, animated: true)
  }

  }

//设置界面
extension ViewController{
 fileprivate func setUpUI() {
    let btn = UIButton(frame: CGRect(x: 0, y: 0, width: 100, height: 30))
    btn.center = self.view.center
    btn.backgroundColor = UIColor.cyan
    btn.addTarget(self, action: #selector(btnAction), for: .touchUpInside)
    btn.setTitle("进第二个界面", for: UIControlState.normal)
    self.view .addSubview(btn)
    tf = UITextField(frame: CGRect(x: 0, y: 0, width: 100, height: 30))
    tf.center = self.view.center
    tf.frame.origin.y = 200
    tf.backgroundColor = UIColor.blue
    self.view.addSubview(tf)
  }

}


 //第二个界面DetailViewController

import UIKit

class DetailViewController: UIViewController {
    var tf:UITextField!

override func viewDidLoad() {
    super.viewDidLoad()
    self.view.backgroundColor = UIColor.white
    setUpUI()
}

//点击按钮返回上一界面
func btnAction()  {
 navigationController?.popViewController(animated: true)

}


extension DetailViewController{

fileprivate func setUpUI() {
  
    let btn = UIButton(frame: CGRect(x: 0, y: 0, width: 100, height: 30))
    btn.center = self.view.center
    btn.backgroundColor = UIColor.cyan
    btn.addTarget(self, action: #selector(btnAction), for: .touchUpInside)
    btn.setTitle("返回第一个界面", for: UIControlState.normal)
    self.view .addSubview(btn)
    tf = UITextField(frame: CGRect(x: 0, y: 0, width: 100, height: 30))
    tf.center = self.view.center
    tf.frame.origin.y = 200
    tf.text = tfStr
    tf.backgroundColor = UIColor.blue
    self.view.addSubview(tf)
}
}

import UIKit
class DetailViewController: UIViewController {
var tf:UITextField!
 //String类型的tfStr属性
var tfStr:String!
  
 override func viewDidLoad() {
    super.viewDidLoad()
  }
}

func btnAction()  {
let vc = DetailViewController()
    vc.tfStr = tf.text
 navigationController?.popViewController(animated: true)

}

 tf.text = tfStr

class DetailViewController: UIViewController {
var tfStr:String!
var tf:UITextField!
override func viewDidLoad() {
    super.viewDidLoad()
    self.view.backgroundColor = UIColor.white
    setUpUI()
    
}

 // 析构器

deinit {
    print(#function)
}
// 自定义构造器
init(text:String) {
    print(#function)
    print(text)
    tfStr = text
    // 指定构造器必须调用它最近父类的指定构造器
    super.init(nibName: nil, bundle: nil)
}
// init(coder aDecoder: NSCoder) 方法是来自父类的指定构造器, 因为这个构造器是 required, 必须要实现。但是因为我们已经重载了 init(), 定义了一个指定构造器, 所以这个方法不会被继承, 需要要手动覆写。

required init?(coder aDecoder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
}



func btnAction()  {

 navigationController?.popViewController(animated: true)

  }

}

@objc fileprivate func btnAction()  {
    let vc = DetailViewController(text: tf.text!)
    navigationController?.pushViewController(vc, animated: true)
    
}

//1.    open func addObserver(_ observer: Any, selector aSelector: Selector, name aName: NSNotification.Name?, object anObject: Any?)

//2.    open func post(name aName: NSNotification.Name, object anObject: Any?, userInfo aUserInfo: [AnyHashable : Any]? = nil)

 NotificationCenter.default.addObserver(forName: NSNotification.Name?, object: Any?, queue: OperationQueue?) { (Notification) in
        //拿到Notification内容进行逻辑处理....
    }

open func post(name aName: NSNotification.Name, object anObject: Any?, userInfo aUserInfo: [AnyHashable : Any]? = nil)

 func btnAction()  {

    NotificationCenter.default.post(name: NSNotification.Name(rawValue: "notifyName"), object: nil, userInfo: ["text": self.tf.text])
     navigationController?.popViewController(animated: true)

}

 class ViewController: UIViewController {
  fileprivate var tf:UITextField = UITextField()
  override func viewDidLoad() {
    super.viewDidLoad()

    NotificationCenter.default.addObserver(forName: NSNotification.Name(rawValue: "notifyName"), object: nil, queue: OperationQueue.main) { (text) in
//这里拿到通知传来的数据text,然后进行逻辑处理,我们这里是为tf.text 赋值
        self.tf.text = "\(text.userInfo?["text"])"
    }
    setUpUI()
 
}

deinit {
    NotificationCenter.default.removeObserver(self)
}

import Foundation
class Singleton{
 // 单例属性，用于传值；
var text : String!
static let singleton = Singleton()
// 获取单例实例方法
func share() -> Singleton {
    return .singleton
}

// 私有化init初始化方法，防止通过此方法创建对象
private init(){
  }

}

//第一个界面赋值
 override func viewDidLoad() {
    super.viewDidLoad()

    setUpUI()
    let singleton = Singleton.singleton.share()
    singleton.text = "我叫MangoJ"
    
}
//第二个界面任意位置都可获取单例属性的值本例在viewDidLoad中
 override func viewDidLoad() {
    super.viewDidLoad()
    self.view.backgroundColor = UIColor.white
    tfStr = Singleton.singleton.share().text
    print(tfStr)
    setUpUI()
}

import UIKit

//1.声明协议
@objc protocol DetailViewControllerDelegate {
//2.设置协议中的方法
  @objc optional func viewController(viewController:DetailViewController,popWithValue:String)->Void
}

class DetailViewController: UIViewController {
//3.声明协议属性
 // 代理属性delegate值为实现了DetailViewControllerDelegate协议的任意对象，weak关键字主要为了防止循环引用导致对象无法释放。
weak var delegate : DetailViewControllerDelegate!
  

var tfStr:String!
var tf:UITextField!

override func viewDidLoad() {
    super.viewDidLoad()
    self.view.backgroundColor = UIColor.white
   
    setUpUI()
}

func btnAction()  {

 navigationController?.popViewController(animated: true)

  }

}

func btnAction()  {

    if let delegate = self.delegate {
        delegate.viewController!(viewController: self, popWithValue: "MangoJ")
    }
    
 navigationController?.popViewController(animated: true)
    
}

  //点击进入第二个界面的按钮进行跳转操作
 @objc fileprivate func btnAction()  {
  
    let vc = DetailViewController()
    //设置代理
    vc.delegate = self
    
    navigationController?.pushViewController(vc, animated: true)
    
}

 // MARK:- DetailViewControllerDelegate -  
 func viewController(viewController: DetailViewController, popWithValue: String) {
    tf.text = popWithValue
}

import UIKit

class DetailViewController: UIViewController {
 // 1、声明闭包类型
typealias ClosureName = (String)->()
// 2、声明闭包属性
var closure : ClosureName!

var tfStr:String!
var tf:UITextField!

override func viewDidLoad() {
    super.viewDidLoad()
    self.view.backgroundColor = UIColor.white
   
    setUpUI()
}

 3.设置闭包传值调用方法
func callBack(closure:@escaping ClosureName)  {
    self.closure = closure
}

func btnAction()  {
  
      5、可选绑定：判断closure属性是否不为nil，如果不为nil，则通过closure将文本信息回调到调用closure方法所在的控制器中；
    guard (self.closure != nil) else {
        return
    }

    closure(tf.text!)
    
 navigationController?.popViewController(animated: true)

  }

}

 //第一个界面的如下方法中
@objc fileprivate func btnAction()  {
  
    let vc = DetailViewController()
 
    vc.callBack { (value) in
        self.tf.text = value
    }
    navigationController?.pushViewController(vc, animated: true)
    
}

 @objc fileprivate func btnAction()  {
  
    // 获取defaults单例实例
 let defaults = UserDefaults.standard
    //设值
    defaults.setValue(tf.text, forKey: "text")
    // 同步数据
    defaults.synchronize()
    
    let vc = DetailViewController()
 
    navigationController?.pushViewController(vc, animated: true)
    
}

override func viewDidLoad() {
    super.viewDidLoad()
    self.view.backgroundColor = UIColor.white
    
   let defalts = UserDefaults.standard
    
    guard let text = defalts.object(forKey: "text") as! String? else {
        return
    }
    tfStr = text
    setUpUI()
}