use a slider while pressing button swift - swift

Question

Using Xcode 8, Swift 3 and Interface Builder with Storyboards and a very basic view controller featuring only a button (Play) and a slider (volume).
I'm trying to use my NSSlider while pressing a button at the same time. For instance, I need to be able to keep pressing "Play" while slowly lowering the volume. What happens instead is that only one button can be in use at a time. So, as long as I am pressing "Play" using the return key, I can't adjust the volume and vice versa.
In this example, the Play button is triggered by the "return" key.
Here is the code in ViewController.swift. This is just an example app I created quickly to study the problem.
Is there an Interface Builder setting on the NSSLider that I am missing, or can I do something in my code to achieve what I am trying to do?
import Cocoa
import AVFoundation
class ViewController: NSViewController {
var audioPlayer = AVAudioPlayer()
var sliderValue: Float = 0
#IBOutlet weak var volumeSliderOutlet: NSSlider!
override func viewDidLoad() {
super.viewDidLoad()
do{
audioPlayer = try AVAudioPlayer(contentsOf: URL.init(fileURLWithPath: Bundle.main.path(forResource: "bell ding", ofType: "wav")!))
}
catch {
print(error)
}
audioPlayer.prepareToPlay()
// Do any additional setup after loading the view.
}
#IBAction func playButtonAction(_ sender: NSButton) {
if audioPlayer.isPlaying {
audioPlayer.currentTime = 0.0
audioPlayer.play()
} else {
audioPlayer.prepareToPlay()
audioPlayer.play()
}
}
#IBAction func volumeSliderAction(_ sender: NSSlider) {
if audioPlayer.isPlaying {
sliderValue = self.volumeSliderOutlet.floatValue
audioPlayer.volume = sliderValue
} else {
return
}
}
override var representedObject: Any? {
didSet {
// Update the view, if already loaded.
}
}
}
I've also tried this, based on advice from #inspector_60, but it doesn't work either. Still can't handle the slider while continuing to press the shortcut key for the button "return".
override func keyDown(with event: NSEvent) {
if (event.keyCode == 36) {
self.playButtonAction(nil)
}
else {
return
}
}
func playButtonAction(_ sender: NSButton?) {
if audioPlayer.isPlaying {
audioPlayer.currentTime = 0.0
audioPlayer.play()
} else {
audioPlayer.prepareToPlay()
audioPlayer.play()
}
}

Answer 1

IBAction are UI events so not suitable for multiple simultaneous clicks (you have only one mouse pointer). Use handling key events in order to handle keyboard events for simultaneous actions.
You need to also implement the mouse events, these links should help:
Apple document about mouse events and specifically Filtering Out Key Events During Mouse-Tracking Operations
This stack overflow answer on how to implement this approach
This post that will give you more information and example - Ron's answer links to a question not that different from yours