How to make sure text field enters a number

To ensure a text field only accepts numbers, you can use various techniques depending on the platform and framework you are working with. Here are some relevant methods from the WWDC sessions:

1. Using Formatters in Localization:

   • In the session Build multilingual-ready apps, it is mentioned that you can use formatters to ensure numbers follow locale-specific rules. This can be useful if you want to ensure that the text field respects the user's language and region settings.

2. Text Entry Suggestions in AppKit:

   • The session What’s new in AppKit introduces a new API for text entry suggestions. While this is more about providing custom suggestions, it can be adapted to ensure that only numeric suggestions are provided, thus guiding the user to enter numbers.

3. SwiftUI Text Field Enhancements:

   • In the session What’s new in SwiftUI, there are enhancements to text fields, including programmatic control of text selection and suggestions. You can use these features to restrict input to numbers by validating the input and providing appropriate feedback or suggestions.

4. Custom Text Views:

   • The session Get started with Writing Tools discusses how to handle custom text views. You can implement delegate methods to validate the input and ensure only numbers are entered.

For a more specific implementation, you might need to combine these techniques with platform-specific APIs to restrict input to numeric values. If you need a detailed code example or further assistance, please specify the platform (iOS, macOS, etc.) and framework (UIKit, SwiftUI, etc.) you are working with.