## NSAlertController
NSAlertController is a class that provides a modern and customizable way to display alerts and modal dialogs in macOS applications. It was introduced in macOS 10.11 as a replacement for the deprecated `NSAlert` class.
### Features
#### 1. Customizable Appearance
NSAlertController offers extensive customization options for the appearance of alerts and dialogs. Developers can specify the style, font, background color, and border color to match the application’s design guidelines.
#### 2. Multiple Alert Styles
NSAlertController supports different alert styles to accommodate various types of messages. The available styles include:
1. Informational: Presents information to the user.
2. Warning: Alerts the user about potential issues.
3. Error: Indicates critical errors and problems.
4. Success: Confirms successful operations.
#### 3. Action Buttons and Completion Handlers
NSAlertController allows developers to add action buttons with customizable titles and styles. Completion handlers can be assigned to each button to specify actions to be performed when the button is clicked. This makes it easy to implement interactive alerts that respond to user actions.
#### 4. Text Fields and Secure Text Fields
Developers can include text fields and secure text fields in NSAlertController to prompt users for input. This is useful when collecting user input for tasks such as authentication, form completion, or data entry.
#### 5. Accessibility Support
NSAlertController is designed to provide excellent accessibility support out-of-the-box. It supports VoiceOver and other assistive technologies, ensuring that alerts and dialogs are accessible to all users, including those with disabilities.
### Usage
To use NSAlertController in your macOS application, follow these steps:
#### 1. Import the Required Framework
“`objective-c
import Cocoa
import NSAlertController
“`
#### 2. Creating and Presenting an Alert
“`objective-c
// Create an instance of NSAlertController
let alertController = NSAlertController(title: “Alert Title”, message: “This is an alert message.”)
// Set the alert style (e.g., .warning, .informational)
alertController.alertStyle = .warning
// Add action buttons (optional)
alertController.addActionButton(withTitle: “OK”, style: .default) {
// Perform action when OK button is clicked
}
alertController.addActionButton(withTitle: “Cancel”, style: .destructive) {
// Perform action when Cancel button is clicked
}
// Present the alert
alertController.present()
“`
### Example
“`objective-c
import Cocoa
import NSAlertController
class ViewController: NSViewController {
override func viewDidLoad() {
super.viewDidLoad()
// Create an instance of NSAlertController
let alertController = NSAlertController(title: “Welcome!”, message: “Thank you for using our app.”)
// Set the alert style
alertController.alertStyle = .informational
// Add an action button
alertController.addActionButton(withTitle: “Continue”, style: .default) {
// Perform action when Continue button is clicked
}
// Present the alert
alertController.present()
}
}
“`
### Compatibility
NSAlertController is compatible with macOS 10.11 and later.
### Conclusion
NSAlertController provides a flexible and visually appealing way to present alerts and modal dialogs in macOS applications. Its customizable appearance, multiple alert styles, and support for action buttons make it a powerful tool for enhancing the user experience. By using NSAlertController, developers can ensure their alerts align with the application’s design guidelines and provide a seamless user interaction.