[ios]簡易なアラートダイアログを表示する

ios-simple-alert.md

extension UIViewController {
    // 簡易なアラートダイアログを表示する
    func showSimpleAlert(title: String?, message: String?, action: ((UIAlertAction) -> Void)? = nil) {
        let alertController = UIAlertController(title: title,
                                                message: message,
                                                preferredStyle: .alert)
        let defaultAction = UIAlertAction(title: "OK",
                                          style: .default,
                                          handler: action)
        alertController.addAction(defaultAction)

        present(alertController, animated: true, completion: nil)
    }
}

// 使い方例
self.showSimpleAlert(title: "hogehoge", message: "hello")

self.showSimpleAlert(title: nil, message: "hello", action: { _ in
    self.navigationController?.popViewController(animated: true)
    })