How to play audio, even when mute button is on? - objective-c

Question

I'm trying to play an audio file when a button is tapped.
If I step through my code it works, but if I just tap on the button no sound is played.
Here is my code:
[[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayback error:nil];
AVAudioPlayer * player;
NSString * path = [[NSBundle mainBundle] pathForResource:#"soundOne" ofType:#"mp3"];
NSURL * url = [NSURL fileURLWithPath:path];
player = [[AVAudioPlayer alloc] initWithContentsOfURL:url error:nil];
[player play];
Is this the appropriate way to play audio? Nothing is being flagged as being deprecated.
I also see this message in the debugger:
AudioQueue: request to trim 0 + 2690 = 2690 frames from buffer containing 1152 frames
EDIT:
This code works.
NSString *filePath = [[NSBundle mainBundle] pathForResource:#"soundOne"
ofType:#"mp3"];
NSURL *fileURL = [[NSURL alloc] initFileURLWithPath:filePath];
self.audioPlayer = [[AVAudioPlayer alloc]
initWithContentsOfURL:fileURL error:nil];
[self.audioPlayer prepareToPlay];
self.audioPlayer.currentTime = 0;
[self.audioPlayer play];
How can I play audio with the mute button on?
Here is the code I have tried for this:
CFStringRef state;
UInt32 propertySize = sizeof(CFStringRef);
OSStatus audioStatus = AudioSessionGetProperty(kAudioSessionProperty_AudioRoute, &propertySize, &state);
if (audioStatus == kAudioSessionNoError) {
//NSLog(#"audio route: %#", state);
return (CFStringGetLength(state) <+ 0);
}
return NO;

Answer 1

Stick this before you call play:
[[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayback error:&error];
[[AVAudioSession sharedInstance] setActive:YES error:&error];
That should do it.