Alarm clock app in iOS
I have to create an alarm clock app for the iPhone in which user can set alarm time and sound. In doing so, I have used UILocalNotification to set off the alarm.
Now, in UILocalNotification, first we get Notification Alert with option "Close" and "View". If the user taps on "View", then my delegate receives the application:didReceiveLocalNotification: message and the alarm sound plays.
But in the system-native alarm app, we don't see a notification alert; it just directly plays the alarm sound. How can I have my app use this behavior?
Answer
I agree with David. iOS built-in alarm app gets a special treatment from Apple to sound > 30 seconds while in the background. It seems to be using some private API to make it sound for a longer time even when it is in the background or closed. This is not available to other apps built outside of Apple, so don't even try to compete with it. If you buy all Alarm clock apps in the App Store (aka: approved by Apple) and try them one by one, you will see that they lack behind the built-in alarm app in the most important function of an alarm: i.e. "Sounding for a long period, in any state the app is in (active, background, or closed)"
Your best bet to simulate a background alarm is to make use of UILocalNotification for 30 seconds. If you really want to wake up your heavy sleeper, schedule to fire up five of these notifications sixty seconds apart or something like that, in the hopes they will wake up before the 5th notification ends.
Notice that with this method, your user who misses the alarm will get 5 popups on their screen when they wake up (less if they wake up during one of the alarm popups), so they'll be spending their first seconds of their morning closing those popups - not the greatest user experience.
Conclusion: Alarm Clock apps are good for foreground use only. Best Alarm app out there that will work in any state is the built-in Clock app made by Apple.