In iOS, how does one listen to the headset insertion and unplugging event?

First, import the system library

# Import <avfoundation/avfoundation. h>

// Listen to the headset event

[[Avaudiosessionsharedinstance] setdelegate: Self];

// Use this code instead to allow the app sound to continue to play when the screen is locked.

[[Avaudiosessionsharedinstance] setcategory: avaudiosessioncategoryplayback error: Nil];

// Registers the audio route change listener callback function

Audiosessionaddpropertylistener (kaudiosessionproperty_audioroutechange, audioroutechangelistenercallback, self );

Write this code to the location where you want to listen

I personally recommend

-(Bool) Application :( uiapplication *) Application didfinishlaunchingwitexceptions :( nsdictionary *) launchoption

Because it is a global solution, everything can be responded

For example

-(Bool) Application :( uiapplication *) Application didfinishlaunchingwitexceptions :( nsdictionary *) launchoptions

{

Self. Window = [[[uiappswalloc] initwithframe: [[uiscreenmainscreen] bounds] autorelease];

// Log on to VC

Loginviewcontroller * loginvc = [[loginviewcontrolleralloc] init];

Uinavigationcontroller * navnv = [[uinavigationcontrolleralloc] initwithrootviewcontroller: loginvc
];

[Navnvsetnavigationbarhidden: Yes];

[Loginvc release];

// Listen to the headset event

[[Avaudiosessionsharedinstance] setdelegate: Self];

// Use this code instead to allow the app sound to continue to play when the screen is locked.

[[Avaudiosessionsharedinstance] setcategory: avaudiosessioncategoryplayback error: Nil];

// Registers the audio route change listener callback function

Audiosessionaddpropertylistener (kaudiosessionproperty_audioroutechange, audioroutechangelistenercallback, self );

Self. Window. rootviewcontroller = navnv;

[Navnv release];

Self. Window. backgroundcolor = [uicolorwhitecolor];

[Self. windowmakekeyandvisible];

Return yes;

}

// Triggered listening event

Void audioroutechangelistenercallback (void * inuserdata, audiosessionpropertyid inpropertyid, uint32 inpropertyvaluesize, const void * inpropertyvalue
){

// Ensure that this callback was invoked for a route change

If (inpropertyid! = Kaudiosessionproperty_audioroutechange) return;

{

// Determines the reason for the route change, to ensure that it is not

// Because of a category change.

Cfdictionaryref routechangedictionary = (cfdictionaryref) inpropertyvalue;

Cfnumberref routechangereasonref = (cfnumberref) cfdictionarygetvalue (routechangedictionary, cfstr (kaudiosession_audioroutechangekey_reason ));

Sint32 routechangereason;

Cfnumbergetvalue (routechangereasonref, kcfnumbersint32type, & routechangereason );

If (routechangereason = kaudiosessionroutechangereason_olddeviceunavailable ){

// Handle headset unplugged

Dlog (@ "no headphones! ");

} Else if (routechangereason = kaudiosessionroutechangereason_newdeviceavailable ){

// Handle headset plugged in

Dlog (@ "with headphones! ");

}

}

}

OK!