---
title: MFMessageComposeViewControllerTextMessageAvailabilityDidChangeNotification
framework: messageui
role: symbol
role_heading: Global Variable
path: messageui/mfmessagecomposeviewcontrollertextmessageavailabilitydidchangenotification
---

# MFMessageComposeViewControllerTextMessageAvailabilityDidChangeNotification

Posted when the value returned by the canSendText() class method has changed.

## Declaration

```occ
extern NSString * const MFMessageComposeViewControllerTextMessageAvailabilityDidChangeNotification;
```

## Discussion

Discussion Upon receiving this notification, query its userInfo dictionary with the MFMessageComposeViewControllerTextMessageAvailabilityKey key. If the availability of text message sending has changed, your app should invalidate caches and update its user interface as appropriate.

## See Also

### Handling notifications

- [MFMessageComposeViewControllerTextMessageAvailabilityKey](messageui/mfmessagecomposeviewcontrollertextmessageavailabilitykey.md)