Display CFUserNotificationDisplayAlert on iPhone Lock Screen

Question

I m creating an app that has to display CFUserNotificationDisplayAlert even if iPhone Screen is Locked, currently i am using this code

CFOptionFlags responseFlags = 0;
CFUserNotificationDisplayAlert(20.0, 3, NULL, NULL, NULL, CFSTR("Hello"), CFSTR("Hello World"), CFSTR("OK"), NULL, NULL, &responseFlags);

This works great on Home Screen but doesnt pop up if the screen is locked. Is there anything else i have to add to it to make it appear on the Lock Screen as well?

Answer 1

You need to use the kCFUserNotificationAlertTopMostKey key.

extern CFStringRef kCFUserNotificationAlertTopMostKey;
CFStringRef keys[] = {
   kCFUserNotificationAlertTopMostKey,
   kCFUserNotificationAlertHeaderKey,
   kCFUserNotificationAlertMessageKey
};
CFStringRef values[] = {
   kCFBooleanTrue,
   CFSTR("Title"),
   CFSTR("Message")
};
CFDictionaryRef dict = CFDictionaryCreate(NULL, keys, values,     
                                          sizeof(keys)/sizeof(*keys),
                                          &kCFTypeDictionaryKeyCallBacks,
                                          &kCFTypeDictionaryValueCallBacks);
SInt32 err = 0;
CFUserNotificationRef notif = CFUserNotificationCreate(NULL,
          0, kCFUserNotificationPlainAlertLevel, &err, dict);
CFRelease(dict);
...

See http://iphonedevwiki.net/index.php/CFUserNotification for all dialog description keys for iPhone OS ≤ 3.1.

(Note that while it will show on the lock screen, the phone won't wake up by itself.)

Answer 2

CFUserNotification is not supported on the iPhone OS. Push Notifications are the iPhone equivalent.