问题
I am playing a small .wav file using the AudioToolBox.
AudioServicesPlaySystemSound (soundFileObject);
But sometimes it is not playing.
What is the reason?
回答1:
If you're in the Simulator, make sure that in System Prefrences → Sound, that "Play user interface sound effects" is not turned off. If you're on the device, check that the ringer switch is not set to silent.
回答2:
Maybe it's this issue? AudioServicesDisposeSystemSoundID() will stop the sound work before playing.
回答3:
System Preferences → Sound → [x] Play user interface sound — this checkbox helped for me too, it solved the AudioServicesPlaySystemSound(_) issue. But worth noting was that the sample Apple Xcode project "SysSound" worked just fine without checking this box. I'm using the Xcode 4.4.1 for creating own app from scratch. Could there be differencies between projects created with older and newer Xcode tools?
回答4:
Building on user1056521's answer, use the following code:
AudioServicesPlaySystemSoundWithCompletion(soundID, ^{
AudioServicesDisposeSystemSoundID(soundID);
});
where soundID is the SystemSoundID value you got when you called AudioServicesCreateSystemSoundID().
The completion block ensures the sound was played and completed playing before it is disposed of.
回答5:
On the device, go into settings and turn up the volume on Sounds->Ringer and Alerts
回答6:
For those who visit this question later,
AudioServicesPlaySystemSoundID()'s volume is based on system Ringer in range of 0.1 ~ 1.0, not mediaVolume
AudioServicesPlayAlertSoundID()'s volume is based on system Ringer in range of approximately 0.3 ~ 1.0
来源：https://stackoverflow.com/questions/2720623/audioservicesplaysystemsound-not-playing-sounds