swift3中代理和闭包的用法

swift 3 中代理和闭包(Block)的用法

其实Swift中不管是代理还是闭包，个人感觉和OC都差不多

代理，闭包:

1.新建一个类，使其继承自UIView

import UIKit
//定义一个代理
protocol MainViewDelegate {
    func getTextFieldString(string:String);
}
//定义一个block
typealias GetTextFieldBlock = (_ textField:String) -> Void

class MainView: UIView {
    var delegate : MainViewDelegate!
    var textField : UITextField!
    var textFieldBlock : GetTextFieldBlock!
    
    
    func initWithFrame(frame:CGRect) -> MainView {
        self.frame = frame
        CreateUI()
        return self
    }
    
    func CreateUI() -> Void {
        let button1 = UIButton();
        button1.addTarget(self, action:#selector(buttonAction1), for: UIControlEvents.touchUpInside);
        button1.frame = CGRect(x:10,y:100,width:100,height:50)
        button1.backgroundColor = UIColor.red
        self.addSubview(button1)
        
        textField = UITextField()
        textField.frame = CGRect(x:10,y:200,width:100,height:50)
        textField.backgroundColor = UIColor.white
        textField.textColor = UIColor.purple
        self.addSubview(textField)
        
        
        let button2 = UIButton()
        button2.addTarget(self, action: #selector(buttonAction2), for: .touchUpInside)
        button2.frame = CGRect(x:10,y:300,width:100,height:50)
        button2.backgroundColor = UIColor.darkGray
        self.addSubview(button2)
        
    }
    
    func buttonAction1(){
        delegate.getTextFieldString(string: textField.text!)//传值
    }
    
    func buttonAction2() {
        if textFieldBlock != nil {
            textFieldBlock(textField.text!)//传值
        }
    }
    //该方法在外部使用
    func getStringAction(_ getStringBlock:@escaping GetTextFieldBlock) {
        textFieldBlock = getStringBlock
    }
    
    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
        self.endEditing(true)
    }
}

2.在外部调用时：

import UIKit

class ViewController: UIViewController,MainViewDelegate {//遵循代理
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        view.backgroundColor = UIColor.orange;
        createUI()
    }
    
    func createUI() {
        let mainView = MainView().initWithFrame(frame: self.view.bounds)
        mainView.delegate = self
        self.view.addSubview(mainView)
        
        mainView.getStringAction { (string) in
            print("+++ \(string) +++")
        }
    }
    
    func getTextFieldString(string: String) {
        print("=== \(string) ====")
    }
    
   
    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
}