Question

当我的应用处于iPhone/iPod/iPad模式时，我想通过我的background将我的耳机插孔设为PluggedIn或UnPlugged时通知用户。在这里，我有在foreground模式下检测到的代码。

- (void)viewDidLoad
{
    [super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.

     AudioSessionAddPropertyListener(kAudioSessionProperty_AudioRouteChange, audioSessionPropertyListener, nil);
}

BOOL isHeadsetPluggedIn() 
{
    UInt32 routeSize = sizeof (CFStringRef);
    CFStringRef route;

    OSStatus error = AudioSessionGetProperty (kAudioSessionProperty_AudioRoute,
                                          &routeSize,
                                          &route
                                          );
    NSLog(@"%@", route);
    return (!error && (route != NULL) && ([( NSString*)route rangeOfString:@"Head"].location != NSNotFound));
}

void audioSessionPropertyListener(void* inClientData, AudioSessionPropertyID inID,UInt32 inDataSize, const void* inData)
{
    UInt32 audioRouteOverride = kAudioSessionOverrideAudioRoute_Speaker;

    // Determines the reason for the route change, to ensure that it is not
    //      because of a category change.
    CFDictionaryRef routeChangeDictionary = inData;
    CFNumberRef routeChangeReasonRef = CFDictionaryGetValue (routeChangeDictionary,CFSTR (kAudioSession_AudioRouteChangeKey_Reason));

    SInt32 routeChangeReason;
    CFNumberGetValue (routeChangeReasonRef, kCFNumberSInt32Type, &routeChangeReason);

    // "Old device unavailable" indicates that a headset was unplugged, or that the
    //  device was removed from a dock connector that supports audio output.
    //    if (routeChangeReason != kAudioSessionRouteChangeReason_OldDeviceUnavailable)
    //        return;

    if (!isHeadsetPluggedIn())
    {
        AudioSessionSetProperty (kAudioSessionProperty_OverrideAudioRoute,sizeof (audioRouteOverride),&audioRouteOverride);

        NSLog(@"With out headPhone");
    }
    else
    {
        UInt32 audioRouteOverride = kAudioSessionOverrideAudioRoute_Speaker;
        AudioSessionSetProperty (kAudioSessionProperty_OverrideAudioRoute, sizeof(audioRouteOverride), &audioRouteOverride);
        NSLog(@"headPhone");
    }

}

Answer 1

您可以从Apple文档中尝试此操作：

- (void)applicationDidEnterBackground:(UIApplication *)application

{

    bgTask = [application beginBackgroundTaskWithExpirationHandler:^{

        // Clean up any unfinished task business by marking where you

        // stopped or ending the task outright.

        [application endBackgroundTask:bgTask];

        bgTask = UIBackgroundTaskInvalid;

}];



    // Start the long-running task and return immediately.

    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{



        // Do the work associated with the task, preferably in chunks.



        [application endBackgroundTask:bgTask];

        bgTask = UIBackgroundTaskInvalid;

    });

}

我认为Apple已在其文档中提供了这些数据：Background Execution and Multitasking

当我的应用程序处于后台模式时，检测从iPhone插入或拔出耳机插孔

1 个答案: