通过点击 OUTSIDE 弹出窗口，有几篇关于如何解除警报控制器弹出窗口的帖子。但我想通过点击 INSIDE 弹出窗口来关闭警报控制器弹出窗口。
我见过一些＆＃34; Toast＆＃34;喜欢GitHub上的解决方案，但我想用原生iOS代码来做这件事。
我已经在SO周围徘徊，并在几秒钟之后获得了解除警报的代码（如Android Toast）：
class ViewController: UIViewController {
let alertController = UIAlertController(title: "Alert", message: "SO Awesome!", preferredStyle: .alert)
@IBOutlet var alertButton: UIButton!
@IBAction func displayAlert(_ sender: UIButton) {
self.present(alertController, animated: true, completion: {
self.perform(#selector(self.dismissAlert), with: self.alertController, afterDelay: 3)
})
}
// dismiss (close) the alert popup
@objc func dismissAlert(_ alert: UIAlertController) {
alert.dismiss(animated: true, completion: nil)
}
override func viewDidLoad() {
super.viewDidLoad()
}
}
但是，如果我不想等待3秒钟让弹出警报关闭怎么办？我希望能够点击弹出警报来关闭它。 （并且还保留超时功能）
我发现了一些很接近但不完全符合我要求的东西。所以......经过一些工作，我自己回答了这个问题，并在下面提供了完整的答案。
答案 0 :(得分：1)
我在SO上找到的最简单的技巧似乎是添加一个带有动作目标的UIControl，它可以解决任何触摸事件中的AlertController。但是UIControl需要一个框架CGRect才能正常运行。
以下是UIControl的重点：
let dismissControl = UIControl()
// make the dismissControl execute dismissAlert for all touch events
dismissControl.addTarget(self, action: #selector(self.dismissAlert), for: .allTouchEvents)
// NOTE: must use the bounds, not the frame for it to work
self.dismissControl.frame = self.alertController.view.bounds
// add the UIControl on top of the UIAlertControl view
self.alertController.view.addSubview(self.dismissControl)
我探索了4种不同的可能性：
这是一个完整的ViewController （Xcode 9.2，Swift 4），它可以处理所有4种情况：
//
// ViewController.swift
// AlertDemo - Display and dismiss UIAlertControllers with UIControl (no action buttons)
// (similar to Toast on Android OS)
//
// 4 different ways to close a UIAlertController popup window:
//
// 1) Timeout - dismiss an Alert Window after a number of seconds (like Android Toast)
// 2) Tap outside the Alert Window (tap on Alert Window DOES NOT close it)
// 3) Tap the Alert Window (tap anywhere else DOES NOT close it)
// 4) Tap anywhere on the screen (on Alert Window or outside of it) to close it
//
// Created by ByteSlinger on 2018-01-19.
// Copyright © 2018 ByteSlinger. All rights reserved.
//
import UIKit
class ViewController: UIViewController {
let alertController = UIAlertController(title: "Alert", message: "SO Awesome!", preferredStyle: .alert)
let timeoutController = UIAlertController(title: "Timeout", message: "That Alert timed out!", preferredStyle: .actionSheet)
let dismissControl = UIControl()
@IBOutlet var alertButton1: UIButton!
@IBOutlet var alertButton2: UIButton!
@IBOutlet var alertButton3: UIButton!
@IBOutlet var alertButton4: UIButton!
// display a modal popup in the middle, wait for timeout to close
@IBAction func displayAlert1(_ sender: UIButton) {
alertController.message = "You must wait for this Alert to timeout"
self.present(alertController, animated: true, completion: {
self.perform(#selector(self.timeoutAlert), with: self.alertController, afterDelay: 3)
})
}
// display a modal popup in the middle, tap outside popup to close
@IBAction func displayAlert2(_ sender: UIButton) {
alertController.message = "Tap outside this Alert to close"
self.present(alertController, animated: true, completion: {
self.dismissControl.frame = self.alertController.view.superview?.bounds ?? CGRect.zero
self.alertController.view.superview?.insertSubview(self.dismissControl, belowSubview: self.alertController.view)
self.perform(#selector(self.timeoutAlert), with: self.alertController, afterDelay: 3)
})
}
// display a modal popup in the middle, tap on or outside popup to close
@IBAction func displayAlert3(_ sender: UIButton) {
alertController.message = "Tap anywhere to close"
self.present(alertController, animated: true, completion: {
self.dismissControl.frame = self.alertController.view.superview?.bounds ?? CGRect.zero
self.alertController.view.superview?.addSubview(self.dismissControl)
self.perform(#selector(self.timeoutAlert), with: self.alertController, afterDelay: 3)
})
}
// display a modal popup in the middle, tap on popup to close
@IBAction func displayAlert4(_ sender: UIButton) {
alertController.message = "Tap on this Alert to close"
self.present(alertController, animated: true, completion: {
// important - use bounds: alertController.view.frame WILL NOT WORK
self.dismissControl.frame = self.alertController.view.bounds
self.alertController.view.addSubview(self.dismissControl)
self.perform(#selector(self.timeoutAlert), with: self.alertController, afterDelay: 3)
})
}
// close the current alert popup (middle) and display the timeout alert (bottom)
@objc func timeoutAlert(_ alertController: UIAlertController) {
if (alertController == UIApplication.shared.keyWindow?.rootViewController?.presentedViewController) {
timeoutController.message = alertController.message!
alertController.view.willRemoveSubview(self.dismissControl)
alertController.dismiss(animated: true, completion: {
self.present(self.timeoutController,animated: true, completion: {
self.perform(#selector(self.dismissTimeout), with: self.timeoutController, afterDelay: 2)
})
})
}
}
// dimiss (close) the alert popup
@objc func dismissAlert() {
// make sure there are no timeoutAlert calls waiting
NSObject.cancelPreviousPerformRequests(withTarget: self)
alertController.view.willRemoveSubview(self.dismissControl)
alertController.dismiss(animated: true, completion: nil)
}
// dimiss (close) the timeout popup
@objc func dismissTimeout(_ alert: UIAlertController) {
alert.dismiss(animated: true, completion: nil)
}
override func viewDidLoad() {
super.viewDidLoad()
// make the dismissControl execute dismissAlert for all touch events
dismissControl.addTarget(self, action: #selector(self.dismissAlert), for: .allTouchEvents)
// make the buttons a little prettier
alertButton1.layer.cornerRadius = 32
alertButton2.layer.cornerRadius = 32
alertButton3.layer.cornerRadius = 32
alertButton4.layer.cornerRadius = 32
}
}
要使用它，只需在IB中创建4个UIButtons并将它们连接到@IBOutlet变量和函数。
注意：我必须取消执行请求，或者有时警报会被先前的超时取消。 dismissAlert()中的这一行做了诀窍：
NSObject.cancelPreviousPerformRequests(withTarget: self)
以下是GitHub上的完整Xcode项目：AlertDemo
感谢 @Apoc 以及此帖中UIControl的灵感：UIAlertController handle dismiss upon click outside (IPad)。从UIAlertController边界设置UIControl帧是最终使它工作的原因。