自iOS8起，苹果就建议告警框使用UIAlertController来代替UIAlertView和UIActionSheel。下面总结了一些常见的用法（本文代码都已更新至Swift3）
1，简单的应用（同时按钮响应Handler使用闭包函数）
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import UIKitclass ViewController: UIViewController { override func viewDidLoad() { super.viewDidLoad() } override func viewDidAppear(_ animated: Bool){ super.viewDidAppear(animated) let alertController = UIAlertController(title: "系统提示", message: "您确定要离开hangge.com吗？", 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") }) alertController.addAction(cancelAction) alertController.addAction(okAction) self.present(alertController, animated: true, completion: nil) } override func didReceiveMemoryWarning() { super.didReceiveMemoryWarning() }} |
2，除了弹出，还可以使用从底部向上滑出的样式
（注意：如果上拉菜单中有“取消”按钮的话，那么它永远都会出现在菜单的底部，不管添加的次序是如何）
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let alertController = UIAlertController(title: "保存或删除数据", message: "删除数据将不可恢复", preferredStyle: .actionSheet)let cancelAction = UIAlertAction(title: "取消", style: .cancel, handler: nil)let deleteAction = UIAlertAction(title: "删除", style: .destructive, handler: nil)let archiveAction = UIAlertAction(title: "保存", style: .default, handler: nil)alertController.addAction(cancelAction)alertController.addAction(deleteAction)alertController.addAction(archiveAction)self.present(alertController, animated: true, completion: nil) |
3，按钮使用“告警”样式（文字颜色变红，用来来警示用户）
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let okAction = UIAlertAction(title: "好的", style: .destructive, handler: nil) |
4，添加任意数量文本输入框（比如可以用来实现个登陆框）
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import UIKitclass ViewController: UIViewController { override func viewDidLoad() { super.viewDidLoad() } override func viewDidAppear(_ animated: Bool){ super.viewDidAppear(animated) let alertController = UIAlertController(title: "系统登录", message: "请输入用户名和密码", preferredStyle: .alert) alertController.addTextField { (textField: UITextField!) -> Void in textField.placeholder = "用户名" } alertController.addTextField { (textField: UITextField!) -> Void in textField.placeholder = "密码" textField.isSecureTextEntry = true } let cancelAction = UIAlertAction(title: "取消", style: .cancel, handler: nil) let okAction = UIAlertAction(title: "好的", style: .default, handler: { action in //也可以用下标的形式获取textField let login = alertController.textFields![0] let login = alertController.textFields!.first! let password = alertController.textFields!.last! print("用户名：(login.text) 密码：(password.text)") }) alertController.addAction(cancelAction) alertController.addAction(okAction) self.present(alertController, animated: true, completion: nil) } override func didReceiveMemoryWarning() { super.didReceiveMemoryWarning() }} |
5，使用代码移除提示框
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self.presentedViewController?.dismiss(animated: false, completion: nil) |
6，提示框弹出后，过段时间自动移除
下面样例弹出一个不带按钮的消息提示框，过个两秒钟提示框自动消失。
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let alertController = UIAlertController(title: "保存成功!", message: nil, preferredStyle: .alert)//显示提示框self.present(alertController, animated: true, completion: nil)//两秒钟后自动消失DispatchQueue.main.asyncAfter(deadline: DispatchTime.now() + 2) { self.presentedViewController?.dismiss(animated: false, completion: nil)} |
原文出自：www.hangge.com 转载请保留原文链接：http://www.hangge.com/blog/cache/detail_651.html