Swift - UIAlertController

 let alertView = UIAlertController(title: "系统提示", message: "你确定要退出", preferredStyle: .alert)
        let cancelAction = UIAlertAction(title: "取消", style: .cancel, handler: nil)
        let okAction = UIAlertAction(title: "好的", style: .default, handler: {
            action in
            print("点击了确定")
        })
        alertView.addAction(cancelAction)
        alertView.addAction(okAction)
        self.present(alertView, animated: true, completion: nil)

let alertView = UIAlertController(title: "系统提示", message: "你确定要退出", preferredStyle: .actionSheet)
        let cancelAction = UIAlertAction(title: "取消", style: .cancel, handler: nil)
        let doNotAction = UIAlertAction(title: "不确定", style: .destructive, handler: nil)
        let okAction = UIAlertAction(title: "好的", style: .default, handler: {
            action in
            print("点击了确定")
        })
        alertView.addAction(cancelAction)
        alertView.addAction(okAction)
        alertView.addAction(doNotAction)
        self.present(alertView, animated: true, completion: nil)

 

 let alertController = UIAlertController(title: "登录", message: "请输入用户名和密码", preferredStyle:.alert)
        
        alertController.addTextField { (textFeild:UITextField!) in
            textFeild.placeholder = "用户名"
        }
        alertController.addTextField { (textFeild:UITextField!) in
            textFeild.placeholder = "密码"
            textFeild.isSecureTextEntry = true
        }
        
        let cancel = UIAlertAction(title: "取消", style:.cancel, handler: nil)
        let ok = UIAlertAction(title: "确定", style: .default) { (action:UIAlertAction) in
            
            let login = alertController.textFields!.first!
            let password = alertController.textFields!.last!
            print("用户名：\(login.text) 密码：\(password.text)")
        }
        
        alertController.addAction(cancel)
        alertController.addAction(ok)
        self.present(alertController, animated: true, completion: nil)

let alertController = UIAlertController(title: "保存成功", message: nil, preferredStyle: .alert)
      self.present(alertController, animated: true, completion: nil)
        
        DispatchQueue.main.asyncAfter(deadline: DispatchTime.now() + 2) {
            self.presentedViewController?.dismiss(animated: false, completion: nil)
        }

 

UIAlertController扩展（UIAlertExtension.swift）

import UIKit
 
extension UIAlertController {
    //在指定视图控制器上弹出普通消息提示框
    static func showAlert(message: String, in viewController: UIViewController) {
        let alert = UIAlertController(title: nil, message: message, preferredStyle: .alert)
        alert.addAction(UIAlertAction(title: "确定", style: .cancel))
        viewController.present(alert, animated: true)
    }
     
    //在根视图控制器上弹出普通消息提示框
    static func showAlert(message: String) {
        if let vc = UIApplication.shared.keyWindow?.rootViewController {
            showAlert(message: message, in: vc)
        }
    }
     
    //在指定视图控制器上弹出确认框
    static func showConfirm(message: String, in viewController: UIViewController,
                            confirm: ((UIAlertAction)->Void)?) {
        let alert = UIAlertController(title: nil, message: message, preferredStyle: .alert)
        alert.addAction(UIAlertAction(title: "取消", style: .cancel))
        alert.addAction(UIAlertAction(title: "确定", style: .default, handler: confirm))
        viewController.present(alert, animated: true)
    }
     
    //在根视图控制器上弹出确认框
    static func showConfirm(message: String, confirm: ((UIAlertAction)->Void)?) {
        if let vc = UIApplication.shared.keyWindow?.rootViewController {
            showConfirm(message: message, in: vc, confirm: confirm)
        }
    }
}

 调用

//弹出普通消息提示框
UIAlertController.showAlert(message: "保存成功!")
 
//弹出确认选择提示框
UIAlertController.showConfirm(message: "是否提交?") { (_) in
    print("点击了确认按钮!")
}