[Swift 4] 경고창 (Alert) - UIAlertController

UIAlertController - Apple Developer Documentation

Swift

    // MARK: UIAlertController - Apple Developer Documentation
    let alert = UIAlertController(title: "My Alert", message: "This is an alert.", preferredStyle: .alert)
    alert.addAction(UIAlertAction(title: NSLocalizedString("OK", comment: "Default action"), style: .default, handler: { _ in
        NSLog("The \"OK\" alert occured.")
    }))
    self.present(alert, animated: true, completion: nil)

Title + OK

Swift 4

	let alert = UIAlertController(title: "Alert", message: nil, preferredStyle: .alert)
	let action = UIAlertAction(title: "OK", style: .default, handler: nil)
	alert.addAction(action)
	present(alert, animated: true, completion: nil)

Title + message + OK

Swift 4

	let alert = UIAlertController(title: "Alert", message: "message", preferredStyle: .alert)
	let action = UIAlertAction(title: "OK", style: .default, handler: nil)
	alert.addAction(action)
	present(alert, animated: true, completion: nil)

Title + message + OK + Cancel

Swift 4

	let alert = UIAlertController(title: "Alert", message: "message", preferredStyle: .alert)
	let action = UIAlertAction(title: "OK", style: .default, handler: nil)
	let cancel = UIAlertAction(title: "Cancel", style: .cancel, handler: nil)
	alert.addAction(action)
	alert.addAction(cancel)
	present(alert, animated: true, completion: nil)

Title + message + Delete + Cancel

Swift 4

    let alert = UIAlertController(title: "Alert", message: "message", preferredStyle: .alert)
    let action = UIAlertAction(title: "Delete", style: .destructive) { (action) in
        // Delete Code
    }
    let cancel = UIAlertAction(title: "Cancel", style: .cancel, handler: nil)
    alert.addAction(action)
    alert.addAction(cancel)
    present(alert, animated: true, completion: nil)

Etc

Action 버튼을 추가하지 않으면 강제종료 시켜야 하는 무서운 일이 벌어집니다. ㅋㅋ