CODEWITHSUNDEEP
objective-cios4
Shingo Yabuki
Shingo Yabuki

Reputation: 43

Objective-C: volumeChanged wasn't called even add a Observer for AVSystemController_SystemVolumeDidChangeNotification?

- (void)viewDidLoad {
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(volumeChanged:) name:@"AVSystemController_SystemVolumeDidChangeNotification" object:nil];
}

- (void)volumeChanged:(NSNotification *)notification{

    float volume = [[[notification userInfo] objectForKey:@"AVSystemController_AudioVolumeNotificationParameter"] floatValue];
    //[self innerSetVolume:volume];
}

volumeChanged will not be called when I push the up/down hardware volume button on device. somebody met the question before?

PS:my test device is iPod touch with iOS 4.3, not iPhone.

Upvotes: 4

Views: 2733

Answers (1)

Michael Dautermann
Michael Dautermann

Reputation: 89549

I believe you need to start up Audio Session Services in order for those notifications to fire.

Here's the documentation for the call -- http://developer.apple.com/library/ios/documentation/AudioToolbox/Reference/AudioSessionServicesReference/Reference/reference.html#//apple_ref/c/func/AudioSessionSetActive

Upvotes: 2

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