I'd like to make an app that plays audio on a certain event occurring while the user is on a phone call.
in the info.plist i set the uibackgroundModes to audio but will it be rejected if the audio is not continuous ? I've read the docs that the audio should be continuous but i'm not sure how to interpret this.
to be more through, here is my end goal: when user is on a phone call i will listen for a new notification and then play a sound, this is the end goal. Can someone help me to figure out if this is possible or will it be rejected in the approval process.
Since you're trying to do something which is related to the Operating System (ie have interaction with a call), you cannot do that. AudioBackgroundMode should only be used to keep playing music / audio when the user leaves the app. If the app stopped playing music/audio, then it couldn't start playing sounds through this mode.
There is a new feature on iOS 7 and 8 which is background services. You should check on that. Services such as Google maps still go on even on background mode, if allowed by the user.