Swift 4带有AVPlayer的UISlider不会滑动

Question

I am trying to control the audio with the UISlider , the print() statement prints the correct value and the app doesn't crash, however when I try to grab it and move the slider (the thumb tint), the UISlider doesn't slide but just moves a bit when I try to slide it ( like a tap ). When I comment the 6th row the slider response correctly (But of course nothing happens).

var playerItem : AVPlayerItem?
var player : AVPlayer?    
@IBAction func adjustSongProgress(_ sender: UISlider) {
    player?.pause()
    let floatTime = Float(CMTimeGetSeconds(player!.currentTime()))
    sliderProgressOutlet.value = floatTime
    print(floatTime)
    player?.play()
}

Answer 1

iOS Slider takes value between 0 to 1. if CMTimeGetSeconds return value outside from 0 to 1 it will not set properly.

therefor you have to convert your Time range to slider range.

for ex : your video/audio length is 120 second and you want to move slider to 30 second.than you can calculate new value using below function.

OldRange = (OldMax - OldMin)
NewRange = NewMax - NewMin

NewValue = (((OldValue - OldMin) * NewRange) / OldRange) + NewMin

oldRange = 120 - 0
newRange = 1 - 0
New value = (30-0)*1/120+0 = 0.25

Answer 2

Fixed it by deleting AVPlayer and changing AVPlayerItem to AVAudioPlayer , then putting the song URL into data : `

    //DOWNLOADS THE SONG IN THE URL AND PUTS IT IN DATA
    var task: URLSessionTask? = nil

    if let songUrl = songUrl {
        task = URLSession.shared.dataTask(with: songUrl, completionHandler: { data, response, error in
            // SELF.PLAYER IS STRONG PROPERTY
            if let data = data {
                self.playerItem = try? AVAudioPlayer(data: data)
                self.playPause()
                DispatchQueue.main.async {
                    self.sliderProgress()
                }
            }
        })
        task?.resume()`

Then I changed UISlider IBAction Value Changed to Touch Down and Touch Up Inside when I connected it to the ViewController :

    // TOUCH DOWN
@IBAction func SliderTouchDown(_ sender: UISlider) {
    playerItem?.pause()
}

//TOUCH UP INSIDE
@IBAction func SliderTouchUpInside(_ sender: UISlider) {
    playerItem?.currentTime = TimeInterval(sliderProgressOutlet.value)
    playerItem?.play()
}