单击按钮时如何打开电话设置？

使用

UIApplication.openSettingsURLString

Swift 5.1更新

 override func viewDidAppear(_ animated: Bool) {    let alertController = UIalertController (title: "Title", message: "Go to Settings?", preferredStyle: .alert)    let settingsAction = UIalertAction(title: "Settings", style: .default) { (_) -> Void in        guard let settingsUrl = URL(string: UIApplication.openSettingsURLString) else { return        }        if UIApplication.shared.canOpenURL(settingsUrl) { UIApplication.shared.open(settingsUrl, completionHandler: { (success) in     print("Settings opened: (success)") // Prints true })        }    }    alertController.addAction(settingsAction)    let cancelAction = UIalertAction(title: "Cancel", style: .default, handler: nil)    alertController.addAction(cancelAction)    present(alertController, animated: true, completion: nil)}

斯威夫特4.2

override func viewDidAppear(_ animated: Bool) {    let alertController = UIalertController (title: "Title", message: "Go to Settings?", preferredStyle: .alert)    let settingsAction = UIalertAction(title: "Settings", style: .default) { (_) -> Void in        guard let settingsUrl = URL(string: UIApplicationOpenSettingsURLString) else { return        }        if UIApplication.shared.canOpenURL(settingsUrl) { UIApplication.shared.open(settingsUrl, completionHandler: { (success) in     print("Settings opened: (success)") // Prints true })        }    }    alertController.addAction(settingsAction)    let cancelAction = UIalertAction(title: "Cancel", style: .default, handler: nil)    alertController.addAction(cancelAction)    present(alertController, animated: true, completion: nil)}