Swift AVAudioPlayer's playing status always be true? - ios

Question

Here's my code:
#objc func playSmusic1() {
guard let url = Bundle.main.url(forResource: "Snote6", withExtension: "wav") else { return }
do {
try AVAudioSession.sharedInstance().setCategory(AVAudioSessionCategoryPlayback)
try AVAudioSession.sharedInstance().setActive(true)
player = try AVAudioPlayer(contentsOf: url, fileTypeHint: AVFileType.wav.rawValue)
guard let player = player else { return }
while (true) {
player.play()
player.enableRate = true;
player.rate = playrate
if !player.isPlaying {
break
}
}
} catch let error {
print(error.localizedDescription)
}
}
I found player.isPlaying properties always be true, so sometimes a tone will be play for 2 or 3 times. How to fix this bug? Thanks a lot!

Answer 1

First: Don't use while(true) for checking because it blocks the main thread!
You should add KVO observer to check this property asynchronously e.g.:
class YourController : UIViewController {
var player: AVAudioPlayer?
//...
deinit {
player?.removeObserver(self, forKeyPath: #keyPath(AVAudioPlayer.isPlaying))
}
func play() {
//...
player?.addObserver(self,
forKeyPath: #keyPath(AVAudioPlayer.isPlaying),
options: .new,
context: nil)
player?.play()
}
override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
if keyPath == #keyPath(AVAudioPlayer.isPlaying) {
if let isPlaying = player?.isPlaying {
print(isPlaying)
}
}
else {
self.observeValue(forKeyPath: keyPath, of: object, change: change, context: context)
}
}
}