我试图将滑块设置为正在播放的音频文件的当前值。但是在设置滑块的值时我遇到了问题。
当我使用 ViewDidLoad 中的计时器时：
self.timer = Timer.scheduledTimer(timeInterval: 0.1, target: self, selector: #selector(PlayerViewController.audioSliderUpdate), userInfo: nil, repeats: true)
它调用我的函数：
func audioSliderUpdate() {
var currentTime : CMTime = (self.audioPlayerItem?.currentTime())!
var seconds : Float64 = CMTimeGetSeconds(currentTime)
var time : Float = Float(seconds)
self.audioSlider.value = time
}
音轨开始跳跃，滑块在跳跃，并将其返回到控制台：
[aqme] 255: AQDefaultDevice (173): skipping input stream 0 0 0x0
当我尝试使用此代码设置最大值时：
let duration : CMTime = (self.audioPlayerItem?.duration)!
let seconds : Float64 = CMTimeGetSeconds(duration)
let maxTime : Float = Float(seconds)
self.audioSlider.valueMaximum = maxTime
我收到此错误：
<Error>: Error: this application, or a library it uses, has passed an invalid numeric value (NaN, or not-a-number) to CoreGraphics API and this value is being ignored. Please fix this problem.
Jan 20 07:24:23 ParseStarterProject-Swift[2441] <Error>: If you want to see the backtrace, please set CG_NUMERICS_SHOW_BACKTRACE environmental variable.
我已经阅读了所有内容，他们都有简单的解决方案，比如
let floatTime = Float(player.currentTime)
这是行不通的。因为你不能直接将 CMT 转换为在 swift 3 中浮动？？？？
所以我的问题是如何设置滑块的值？
如果我的解释不清楚，这就是整个课程的亮点：
import UIKit
import Parse
import AVFoundation
import AVKit
class PlayerViewController: UIViewController, AVAudioPlayerDelegate {
@IBOutlet var audioSlider: MTCircularSlider!
// passed objectID from PackViewController
var selectedAudio: String!
var audioPlayer: AVPlayer?
var audioPlayerItem: AVPlayerItem?
fileprivate var timer: Timer?
fileprivate var direction: Float = 0.01
// query parse to get the file and stream it
func getAudio() {
let query = PFQuery(className: "Part")
query.whereKey("objectId", equalTo: selectedAudio)
query.getFirstObjectInBackground { (object, error) in
if error != nil || object == nil {
print("The getFirstObject request failed.")
} else {
print("There is an object now get the Audio. ")
if let audioFileURL = (object?.object(forKey: "partAudio") as! PFFile).url {
// create an item for use by notification center
self.audioPlayerItem = AVPlayerItem(url: NSURL(string: audioFileURL) as! URL)
self.audioPlayer = AVPlayer(playerItem: self.audioPlayerItem)
self.audioPlayer?.play()
var duration : CMTime = (self.audioPlayerItem?.duration)!
var seconds : Float64 = CMTimeGetSeconds(duration)
var maxTime : Float = Float(seconds)
self.audioSlider.valueMaximum = maxTime
self.timer = Timer.scheduledTimer(timeInterval: 0.1, target: self, selector: #selector(PlayerViewController.audioSliderUpdate), userInfo: nil, repeats: true)
}
}
}
}
@IBOutlet var playerButton: UIButton!
func playerButtonTapped() {
// if the player is not playing
if audioPlayer?.rate == 0 {
audioPlayer?.play()
self.playerButton.setImage(UIImage(named: "play"), for: UIControlState.normal)
} else {
audioPlayer?.pause()
self.playerButton.setImage(UIImage(named: "pause"), for: UIControlState.normal)
}
}
func finishedPlaying (myNotification: NSNotification) {
self.playerButton.setImage(UIImage(named: "play"), for: UIControlState.normal)
let stoppedPlayerItem: AVPlayerItem = myNotification.object as! AVPlayerItem
//create a CMTime for zero seconds so we can go back to the beginning
let seconds : Int64 = 0
let preferredTimeScale : Int32 = 1
let seekTime : CMTime = CMTimeMake(seconds, preferredTimeScale)
stoppedPlayerItem.seek(to: seekTime)
}
override func viewDidLoad() {
super.viewDidLoad()
self.playerButton.addTarget(self, action: #selector(PlayerViewController.playerButtonTapped), for: UIControlEvents.touchUpInside)
getAudio()
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
NotificationCenter.default.addObserver(audioPlayerItem as Any, selector: #selector(PlayerViewController.finishedPlaying), name: NSNotification.Name.AVPlayerItemDidPlayToEndTime, object: audioPlayer)
}
override func viewWillDisappear(_ animated: Bool) {
super.viewWillAppear(animated)
// remove the observer when leaving page
NotificationCenter.default.removeObserver(audioPlayer?.currentItem! as Any)
}
@IBAction func audioSliderActioned(_ sender: Any) {
audioPlayer?.pause()
//audioPlayer.currentTime() = TimeInterval(audioSlider.value)
//audioPlayer.prepareToPlay()
audioPlayer?.play()
}
func audioSliderUpdate() {
var currentTime : CMTime = (self.audioPlayerItem?.currentTime())!
var seconds : Float64 = CMTimeGetSeconds(currentTime)
var time : Float = Float(seconds)
self.audioSlider.value = time
}
}