objective c - Detecting active AVAudioSessions on iOS device -

i'm trying figure out if possible - app activates audio session initialized as:

[[[avaudiosession alloc] init] setcategory:avaudiosessioncategoryplayback withoptions:avaudiosessioncategoryoptionmixwithothers error:&error]; 

i able understand when additional audio session originated app or os playing.

i know ability implement delegate methods begininterruption: , endinterruption these won't invoked because of avaudiosessioncategoryoptionmixwithothers option i'm using.

is there way achieve without using private api?

thanks in advance.

the way manage application's audio session has had significant changes since ios 6.0, , deserves brief mention first. before ios 6.0 make use of avaudiosession , audiosessionservices classes, incorporating delegation , property listening respectively. ios 6.0 onwards use avaudiosession class , incorporate notifications.

the following ios 6.0 onwards.

to tell if other audio outside applications sandbox playing use -

// query if other audio playing bool isplayingwithothers = [[avaudiosession sharedinstance] isotheraudioplaying]; // test with... (isplayingwithothers) ? nslog(@"other audio playing") : nslog(@"no other audio playing"); 

as interruption handling you'll need observe avaudiosessioninterruptionnotification , avaudiosessionroutechangenotification. in class manages audio session put following - should called once @ start of application lifecycle , don't forget remove observer in dealloc method of same class.

// ensure have singleton object     [avaudiosession sharedinstance];     // register notifications     [[nsnotificationcenter defaultcenter] addobserver:self                                              selector:@selector(interruption:)                                                  name:avaudiosessioninterruptionnotification                                                object:nil];     [[nsnotificationcenter defaultcenter] addobserver:self                                              selector:@selector(routechange:)                                                  name:avaudiosessionroutechangenotification                                                object:nil]; 

and add following selectors interruption: , routechange: - these receive nsnotification object has property called userinfo of type nsdictionary read assist conditionals application has.

- (void)interruption:(nsnotification*)notification { // user info dictionary nsdictionary *interuptiondict = notification.userinfo; // avaudiosessioninterruptiontypekey enum dictionary nsinteger interuptiontype = [[interuptiondict valueforkey:avaudiosessioninterruptiontypekey] integervalue]; // decide based on interruption type here... switch (interuptiontype) {     case avaudiosessioninterruptiontypebegan:         nslog(@"audio session interruption case started.");         // fork handling method here...         // eg:[self handleinterruptionstarted];         break;      case avaudiosessioninterruptiontypeended:         nslog(@"audio session interruption case ended.");         // fork handling method here...         // eg:[self handleinterruptionended];         break;      default:         nslog(@"audio session interruption notification case default.");         break; } } 

and similarly...

- (void)routechange:(nsnotification*)notification {  nsdictionary *interuptiondict = notification.userinfo;  nsinteger routechangereason = [[interuptiondict valueforkey:avaudiosessionroutechangereasonkey] integervalue];  switch (routechangereason) {     case avaudiosessionroutechangereasonunknown:         nslog(@"routechangereason : avaudiosessionroutechangereasonunknown");         break;      case avaudiosessionroutechangereasonnewdeviceavailable:         // headset added or removed         nslog(@"routechangereason : avaudiosessionroutechangereasonnewdeviceavailable");         break;      case avaudiosessionroutechangereasonolddeviceunavailable:         // headset added or removed         nslog(@"routechangereason : avaudiosessionroutechangereasonolddeviceunavailable");         break;      case avaudiosessionroutechangereasoncategorychange:         // called @ start - when other audio wants play         nslog(@"routechangereason : avaudiosessionroutechangereasoncategorychange");//avaudiosessionroutechangereasoncategorychange         break;      case avaudiosessionroutechangereasonoverride:         nslog(@"routechangereason : avaudiosessionroutechangereasonoverride");         break;      case avaudiosessionroutechangereasonwakefromsleep:         nslog(@"routechangereason : avaudiosessionroutechangereasonwakefromsleep");         break;      case avaudiosessionroutechangereasonnosuitablerouteforcategory:         nslog(@"routechangereason : avaudiosessionroutechangereasonnosuitablerouteforcategory");         break;      default:         break; } } 

there no need poll long check state of applications audio session example in viewdidload of root view controller, @ start of apps lifecycle. changes there onwards applications audio session known via these 2 main notifications. replace nslog statements ever code needs based on cases contained in switch.

you can find more information avaudiosessioninterruptiontypekey , avaudiosessionroutechangereasonkey in avaudiosession class reference documentation.

my apologies long answer think audio session management in ios rather fiddly , apple's audio session programming guide, @ time of writing this, not include code examples using notifications interruption handling.