UIAlertController

创建一个警告窗口

import UIKit

class ViewController: UIViewController {
    

    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        let button = UIButton(type: .system)
        button.frame = CGRect(x: 20, y: 120, width: 280, height: 44)
        button.setTitle("Test", for: .normal)
        button.addTarget(self, action: #selector(ViewController.showAlert), for: .touchUpInside)
        self.view.addSubview(button)
        
        
    }
    
    @objc func showAlert() {
        
        let alert = UIAlertController(title: "Information", message: "Are you a student", preferredStyle: .alert)
        
        let yes = UIAlertAction(title: "Yes", style: .default) { (UIAlertAction) in
            print("Yes I am a student ")
        }
        
        let no = UIAlertAction(title: "No", style: .destructive) { (UIAlertAction) in
            print("No I am not a student")
        }
        
        let cancel = UIAlertAction(title: "Cancel", style: .cancel, handler: nil)
        
        alert.addAction(yes)
        alert.addAction(no)
        alert.addAction(cancel)
        self.present(alert, animated: true, completion: nil)
        
    }
    
}

创建一个动作表单

import UIKit

class ViewController: UIViewController {
    

    
    override func viewDidLoad() {
        super.viewDidLoad()
        
      // 创建一个用于展示的按钮
        let button = UIButton(type: .system)
        button.frame = CGRect(x: 20, y: 120, width: 280, height: 44)
        button.setTitle("Test", for: .normal)
        button.addTarget(self, action: #selector(ViewController.showAlert), for: .touchUpInside)
        self.view.addSubview(button)
        
        
    }
    
    @objc func showAlert() {
        
        let actionSheet = UIAlertController(title: "Information", message: "What's your favourite?", preferredStyle: .actionSheet)
        
        let fishing = UIAlertAction(title: "Fishing", style: .default) { (UIAlertAction) in
            print("I like fishing")
        }
        
        let hunting = UIAlertAction(title: "Hunting", style: .destructive) { (UIAlertAction) in
            print("I like hunting")
        }
        
        let nothing = UIAlertAction(title: "Nothing", style: .destructive) { (UIAlertAction) in
            print("A life of Nonsence")
        }
        
        actionSheet.addAction(fishing)
        actionSheet.addAction(hunting)
        actionSheet.addAction(nothing)
        
        self.present(actionSheet, animated: true) {
            print("What's your favourite")
        }
    }
}