An easy to implement simple swift class working on AVAudioPlayer depicting various features like play, pause and stop.

// creating single instance of class
    static let sharedInstance = MyAudioPlayer()
    
    var myAudioPlayer:AVAudioPlayer?
    
    //MARK: Player Key Functions
    
    // checking if playing is running/playing or not
    func isRunningAudio()->Bool{
        
        if let audioPlayer = myAudioPlayer{
            
            return audioPlayer.playing
        }
        return false;
    }
    
    // funtion to play audio
    func playAudio(audio:String, type:String){
        
        if(myAudioPlayer != nil){
            
            myAudioPlayer?.play()
        }
        else{
            
            do{
                
                try myAudioPlayer = AVAudioPlayer(contentsOfURL: NSURL(string: NSBundle.mainBundle().pathForResource(audio, ofType: type)!)!)
                myAudioPlayer?.delegate = self
                myAudioPlayer?.prepareToPlay()
                myAudioPlayer?.play()
            } catch {
                print(error)
            }
        }        
    }
    
    // will pause the current playing audio
    func pauseAudio(){
        
        myAudioPlayer?.pause()
    }
    
    // will stop the player
    func stopAudio(){
        
        if let audioPlayer = myAudioPlayer{
            
            audioPlayer.stop()
            myAudioPlayer = nil
        }
    }
    
    //MARK: Player Delegate
    // delegate method, will be called when audioplayer is finished playing audio
    func audioPlayerDidFinishPlaying(player: AVAudioPlayer, successfully flag: Bool){
        
        if(flag){
        
            myAudioPlayer = nil
        }
    }

    // delegate method, will be called when audioplayer encounters any interruption(like call) while playing audio
    func audioPlayerBeginInterruption(player: AVAudioPlayer){
        
        myAudioPlayer?.pause()
    }
    
    // delegate method, will be called when interruption ends.
    func audioPlayerEndInterruption(player: AVAudioPlayer, withOptions flags: Int){
        
        myAudioPlayer?.play()
    }