Table of Contents

typedef AKRESULT( * AK::SoundEngine::iOS::AudioInterruptionCallbackFunc)(bool in_bEnterInterruption,void *in_pCookie)

iOS-only callback function prototype used for handling audio session interruption. It is mandatory to implement this callback to respond to audio interruptions such as phone calls or alarms according to the application logic. The examples of such responses include calling relevant sound engine API to suspend the device or wake up the device from suspend, and enabling certain UI elements when an interruption happens.

Remarks:
  • Under interruptible (non-mixable) audio session categories, the app needs to respond to audio interruptions such as phone calls, alarms, or the built-in music player control from various remote control interfaces, according to app's own policy. Such a policy may include pausing and resuming the sound engine pipeline, pausing and resuming the entire game, and updating UI elements either as the feedback to users about the interruption status, or as a means for the users to restore the audio manually if the application requires the user intervention.
  • There is no need to call AK::SoundEngine::Suspend() and AK::SoundEngine::WakeupFromSuspend() in this callback. The sound engine call them internally depending on the interruption status.
  • When in_bEnterInterruption is true, this callback is called before the sound engine calls AK::SoundEngine::Suspend(), where user can take actions to prepare for the suspend, e.g., posting global pause events or switching to a special user interface; when in_bEnterInterruption is false, this callback is called after the sound engine calls AK::SoundEngine::WakeFromSuspend() and only when waking up succeeds, so that user can restore suspended resources, e.g., post global resume events or switching back to default user interface. This is useful for games in which audio is essential to the gameplay.
  • Under the AkAudioSessionCategorySoloAmbient audio session category, to avoid remote-control-related audio loss, any pause event posted in this callback when entering interruption needs to be paired with a resume event in the AudioSourceChangeCallbackFunc's conditional branch for when other app's audio is not playing. This is because by Apple's design, under this category, the end of interruption will trigger the source change callback instead of the interruption callback if the interruption source is the user music.
  • Starting from iOS 7, under the AkAudioSessionCategorySoloAmbient audio session category, this callback will be triggered with an end-of-interruption flag when app returns to the foreground from previous backgrounding, e.g., after a home-screen-and-back cycle, or a locking-unlocking cycle. It is triggered after the applicationDidBecomeActive: call. This means that the background music decisions made within applicationDidBecomeActive: can be overriden by the interruption callback.
See also:

Definition at line 149 of file AkiOSSoundEngine.h.