Loop vibration in Swift - ios

Question

I'm playing a sound using AVPlayer. I'm trying to let the iPhone vibrate during this sound.
I'm able to create a vibration with:
AudioServicesPlayAlertSound(kSystemSoundID_Vibrate)
But I'm having problems trying to loop this vibration if I use:
vibrationTimer = Timer.scheduledTimer(timeInterval: 2.0, target: self, selector: #selector(ViewController.loopVibration), userInfo: nil, repeats: true)
#objc func loopVibration() {
AudioServicesPlayAlertSound(kSystemSoundID_Vibrate);
}
The func loopVibration() gets called every two seconds but it doesn't vibrate.

Answer 1

Not sure why this isn't working for you--the following sample works for me on my test device (iPhone X, iOS 11.2).
The ViewController sample below includes outlets for playing single sounds, playing single vibrations, looping sounds and looping vibrations. The "Chirp" sound is a 1s wav file.
Note that since this is a sample, the code below doesn't dispose of the system sounds, nor invalidate timers if the ViewController is hidden. Make sure to manage your system resources appropriately if you adapt this.
//
// ViewController.swift
//
import UIKit
import AudioToolbox
class ViewController: UIViewController {
static let soundId: SystemSoundID? = {
guard let soundURL = Bundle.main.url(forResource: "Chirp", withExtension: "wav") else {
return nil
}
var soundId: SystemSoundID = 0
AudioServicesCreateSystemSoundID(soundURL as CFURL, &soundId)
return soundId
}()
static let timerInterval: TimeInterval = 2
var soundTimer: Timer?
var vibrationTimer: Timer?
var playCount = 0 {
didSet {
playCountLabel.text = String(playCount)
}
}
func invalidateTimers() {
if let vibrationTimer = vibrationTimer {
vibrationTimer.invalidate()
}
if let soundTimer = soundTimer {
soundTimer.invalidate()
}
}
#IBOutlet weak var playCountLabel: UILabel!
#IBAction func playSound(_ sender: Any) {
if let soundId = ViewController.soundId {
AudioServicesPlaySystemSound(soundId)
playCount += 1
}
}
#IBAction func loopSound(_ sender: Any) {
invalidateTimers()
soundTimer = Timer.scheduledTimer(timeInterval: ViewController.timerInterval, target: self, selector: #selector(playSound(_:)), userInfo: nil, repeats: true)
}
#IBAction func vibrate(_ sender: Any) {
AudioServicesPlaySystemSound(kSystemSoundID_Vibrate)
playCount += 1
}
#IBAction func loopVibrate(_ sender: Any) {
invalidateTimers()
soundTimer = Timer.scheduledTimer(timeInterval: ViewController.timerInterval, target: self, selector: #selector(vibrate(_:)), userInfo: nil, repeats: true)
}
#IBAction func cancelAll(_ sender: Any) {
invalidateTimers()
}
}

Answer 2

It's not permitted to use continuous vibration, your app might be rejected. If you still want to do it you can try something like this:
func vibrate() {
for i in 0...13 {
DispatchQueue.main.asyncAfter(deadline: DispatchTime.now() + Double(Int64(Double(i) * 0.1 * Double(NSEC_PER_SEC))) / Double(NSEC_PER_SEC), execute: {
AudioServicesPlayAlertSound(kSystemSoundID_Vibrate)
self.vibrate()
})
}
}