UIKit provides UIAlertController, but it is sometimes annoying to use. You have to get the top UIViewController. I will introduce an easier way to handle UIAlertController.
// AlertController.swift
UIKit
class AlertController: UIAlertController {
private lazy var alertWindow: UIWindow = {
let window = UIWindow(frame: UIScreen.main.bounds)
window.rootViewController = ClearViewController()
window.backgroundColor = UIColor.clear
window.windowLevel = UIWindow.Level.alert
return window
}()
/// Shows a custom alert controller.
func show(animated flag: Bool = true, completion: (() -> Void)? = nil) {
guard let rootVC = alertWindow.rootViewController else { return }
alertWindow.makeKeyAndVisible()
rootVC.present(self, animated: flag, completion: completion)
}
}
private class ClearViewController: UIViewController {
override var preferredStatusBarStyle: UIStatusBarStyle {
return UIApplication.shared.statusBarStyle
}
override var prefersStatusBarHidden: Bool {
return UIApplication.shared.isStatusBarHidden
}
}
You can use AlertController like following. This alert will allow you to show an alert view from anywhere easily. I mean, You don't have to call present(viewControllerToPresent: UIViewController>, animated: Bool, completion: (() -> Void)?) from UIViewController anymore.
func displayAlert() {
let alert = AlertController(title: "Error", message: "Something happened", preferredStyle: .alert)
let action = UIAlertAction(title: "OK", style: .default)
alert.addAction(action)
alert.show()
}
You might want to extend Error like below. You can show an error alert like error.displayAlert(). It's easy, isn't it?
extension Error {
func displayAlert(completion: (() -> Void)? = nil) {
let alert = AlertController(title: "Error", message: localizedDescription, preferredStyle: .alert)
let action = UIAlertAction(title: "OK", style: .default)
alert.addAction(action)
alert.show(completion: completion)
}
}
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