Swift 2 AVAudioSession setCategory extra argument 'error'

问题

When I set up to record audio, I get an error.

if (session.respondsToSelector("requestRecordPermission:")) {
    AVAudioSession.sharedInstance().requestRecordPermission({(granted: Bool)-> Void in
        if granted {
            print("granted")
            session.setCategory(AVAudioSessionCategoryPlayAndRecord, error: nil)
            session.setActive(true, error: nil)
            self.recorder ()
        } else{
            print("not granted")
        }
   })
}

Why do I get an error for having error: nil?

回答1:

Like this:

try! session.setCategory(AVAudioSessionCategoryPlayAndRecord)

Let's see if you can figure out for yourself, from that model, how to fix the next line...

来源：https://stackoverflow.com/questions/32878965/swift-2-avaudiosession-setcategory-extra-argument-error