Swift 使用代理和闭包(closure)反向传值

时间:2022-11-12 22:48:11

FirstViewController的代码

Swift 使用代理和闭包(closure)反向传值
import UIKit
class FirstViewController: UIViewController, SecondViewControllerDelegate { @IBOutlet weak var showTextLabel: UILabel! @IBOutlet weak var showDelegateTextLabel: UILabel! override func viewDidLoad() { super.viewDidLoad() // Do any additional setup after loading the view. } //点击按钮跳转到SecondViewController @IBAction func tapGoSecondViewController(sender: UIButton) { //从storyboard上加载SecondViewController let secondVC = UIStoryboard(name: "Main", bundle: NSBundle.mainBundle()).instantiateViewControllerWithIdentifier("secondViewController") as! SecondViewController //实现回调,获取回调回来的值 (闭包) secondVC.backClosure = { (backStr: String) -> Void in self.showTextLabel.text = backStr } secondVC.delegate = self //跳转到SecondViewController self.navigationController?.pushViewController(secondVC, animated: true) } //MARK: - SecondViewControllerDelegate(代理) func fetchBackString(str: String) { self.showDelegateTextLabel.text = str } override func didReceiveMemoryWarning() { super.didReceiveMemoryWarning() // Dispose of any resources that can be recreated. } }

SecondViewController的代码

Swift 使用代理和闭包(closure)反向传值
import UIKit

//定义闭包类型(特定的函数类型函数类型)
typealias InputClosureType = (String) -> Void

protocol SecondViewControllerDelegate: NSObjectProtocol{
    func fetchBackString(str: String)
}

class SecondViewController: UIViewController {
    
    @IBOutlet weak var inputTextField: UITextField!
    //接收上个页面传过来的闭包块
    var backClosure: InputClosureType?
    weak var delegate: SecondViewControllerDelegate?
    
    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view.
    }

    @IBAction func tapBackButton(sender: UIButton) {
        if self.backClosure != nil {
            if let tempString = self.inputTextField.text {
                self.backClosure!(tempString)
            }
        }
        self.navigationController?.popViewControllerAnimated(true)
    }
    
    @IBAction func delegateBackMethod(sender: UIButton) {
        if self.delegate != nil {
            if let tempString = self.inputTextField.text {
                delegate!.fetchBackString("代理返回数据:\(tempString)")
            }
        }
        self.navigationController?.popViewControllerAnimated(true)
    }
    
    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
}

效果视图:

Swift 使用代理和闭包(closure)反向传值 Swift 使用代理和闭包(closure)反向传值