我正在尝试在我的应用中实现一个小功能。我目前正在播放声音作为AVAudioPlayers并且工作正常。我想补充的是用UISlider控制声音的位置（currentTime）：有一种简单的方法吗？
我查看了一个Apple项目，但它非常混乱....你有样品或建议吗？
感谢大家提前
答案 0 :(得分：48)
应该不是问题 - 只需将滑块设置为连续，并在加载声音文件后将最大值设置为播放器的持续时间。
修改
我刚刚做了这件事，它对我有用......
- (IBAction)slide {
player.currentTime = slider.value;
}
- (void)updateTime:(NSTimer *)timer {
slider.value = player.currentTime;
}
- (IBAction)play:(id)sender {
NSURL *url = [NSURL fileURLWithPath:[[NSBundle mainBundle] pathForResource:@"sound.caf" ofType:nil]];
NSError *error;
player = [[AVAudioPlayer alloc] initWithContentsOfURL:url error:&error];
if (!player) NSLog(@"Error: %@", error);
[player prepareToPlay];
slider.maximumValue = [player duration];
slider.value = 0.0;
[NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(updateTime:) userInfo:nil repeats:YES];
[player play];
}
滑块在IB中配置，以及开始播放的按钮。
var player: AVAudioPlayer!
var sliderr: UISlider!
@IBAction func play(_ sender: Any) {
var url = URL(fileURLWithPath: Bundle.main.path(forResource: "sound.caf", ofType: nil)!)
var error: Error?
do {
player = try AVAudioPlayer(contentsOf: url)
}
catch let error {
}
if player == nil {
print("Error: \(error)")
}
player.prepareToPlay()
sliderr.maximumValue = Float(player.duration)
sliderr.value = 0.0
Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(self.updateTime), userInfo: nil, repeats: true)
player.play()
}
func updateTime(_ timer: Timer) {
sliderr.value = Float(player.currentTime)
}
@IBAction func slide(_ slider: UISlider) {
player.currentTime = TimeInterval(slider.value)
}
答案 1 :(得分：16)
要延伸paull的答案，你可以将滑块设置为连续的音频播放器的duration的最大值，然后添加你的一些对象（可能是视图控制器）作为滑块的目标UIControlEventValueChanged事件;当您收到操作消息时，您可以将AVAudioPlayer的{{1}}属性设置为滑块的值。
您可能还想使用currentTime更新滑块的值，因为音频播放器会播放; NSTimer是最简单的方法。
答案 2 :(得分：7)
我需要调整上面的答案才能让它发挥作用。问题是使用
slider.maximumValue = [player duration];
slider.value = player.currentTime;
player.currentTime = slider.value;
不能正常工作，因为滑块需要浮动，玩家currentTime和dration返回CMTime。为了使这些工作，我改编他们阅读：
slider.maximumValue = CMTimeGetSeconds([player duration]);
slider.value = CMTimeGetSeconds(player.currentTime);
player.currentTime = CMTimeMakeWithSeconds((int)slider.value,1);
答案 3 :(得分：0)
我在播放音频文件，显示开始/结束时间以及使用UISlider控制歌曲时遇到的问题。
此答案需要一些编辑，但毫无疑问会起作用。
//UISlider init
lazy var slider: UISlider = {
let progress = UISlider()
progress.minimumValue = 0.0
progress.maximumValue = 100.0
progress.tintColor = UIColor.init(named: "ApplicationColor")
return progress
}()
var audioPlayer : AVAudioPlayer?
//First I've downloaded the audio and then playing it.
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
timer = Timer.scheduledTimer(timeInterval: 1, target: self, selector: #selector(trackAudio), userInfo: nil, repeats: true)
if let audioURLString = audioURL{
let urlstring = URL(string: audioURLString)!
downloadFromURL(url: urlstring) { (localURL, response, error) in
if let localURL = localURL{
self.playAudioFile(url: localURL)
}
}
}
}
override func viewDidDisappear(_ animated: Bool) {
super.viewDidDisappear(animated)
stopTimer()
}
// Stop TimeInterval After View disappear
func stopTimer() {
if timer != nil {
timer?.invalidate()
audioPlayer?.stop()
audioPlayer = nil
timer = nil
}
}
@objc func sliderSelected(_ sender : UISlider){
if audioPlayer != nil{
if !isPlaying{
self.audioPlayer?.play()
playButton.setImage(UIImage.init(named: "AudioPause"), for: .normal)
isPlaying = true
}else{
self.audioPlayer?.currentTime = TimeInterval(Float(sender.value) * Float(self.audioPlayer!.duration) / 100.0)
if (sender.value / 100.0 == 1.0){
//Do something if audio ends while dragging the UISlider.
}
}
}
}
func downloadFromURL(url:URL,completion: @escaping((_ downladedURL: URL?,_ response :URLResponse?,_ error: Error?) -> Void)){
var downloadTask:URLSessionDownloadTask
downloadTask = URLSession.shared.downloadTask(with: url) {(URL, response, error) in
if let url = URL{
completion(url,nil,nil)
}else if let response = response{
completion(nil,response,nil)
}
if let error = error{
completion(nil,nil,error)
}
}
downloadTask.resume()
}
func playAudioFile(url:URL){
do{
self.audioPlayer = try AVAudioPlayer(contentsOf: url)
self.audioPlayer?.prepareToPlay()
self.audioPlayer?.delegate = self
self.audioPlayer?.play()
let audioDuration = audioPlayer?.duration
let audioDurationSeconds = audioDuration
minutes = Int(audioDurationSeconds!/60);
seconds = Int(audioDurationSeconds!.truncatingRemainder(dividingBy: 60))
} catch{
print("AVAudioPlayer init failed")
}
}
@objc func trackAudio() {
if audioPlayer != nil{
DispatchQueue.main.async {
print("HI")
let normalizedTime = Float(self.audioPlayer!.currentTime * 100.0 / self.audioPlayer!.duration)
self.slider.setValue(normalizedTime, animated: true)
let currentTime = self.audioPlayer?.currentTime
self.currentMinutes = Int(currentTime!/60);
self.currentSeconds = Int(currentTime!.truncatingRemainder(dividingBy: 60))
self.startTimeLabel.text = String(format: "%02i:%02i", self.currentMinutes, self.currentSeconds)
self.endTimeLabel.text = String(format: "%02i:%02i", self.minutes, self.seconds)
}
}
}
答案 4 :(得分：0)
如果有人在 UI 滑块上寻找简单的 TouchDown 和 TouchUp，那么结果很简单：
slider.addTarget(self, action: #selector(changeVlaue(_:)), for: .valueChanged)
slider.addTarget(self, action: #selector(sliderTapped), for: .touchDown)
slider.addTarget(self, action: #selector(sliderUntouched), for: .touchUpInside)
答案 5 :(得分：0)
如果您在拖动之间不需要任何数据，那么您只需设置：
mySlider.isContinuous = false
否则，请尝试以下代码来控制触摸的每个阶段。
// audio slider bar
private lazy var slider: UISlider = {
let slider = UISlider()
slider.translatesAutoresizingMaskIntoConstraints = false
slider.minimumTrackTintColor = .red
slider.maximumTrackTintColor = .white
slider.setThumbImage(UIImage(named: "sliderThumb"), for: .normal)
slider.addTarget(self, action: #selector(onSliderValChanged(slider:event:)), for: .valueChanged)
// slider.isContinuous = false
return slider
}()
@objc func onSliderValChanged(slider: UISlider, event: UIEvent) {
guard let player = AudioPlayer.shared.player else { return }
if let touchEvent = event.allTouches?.first {
switch touchEvent.phase {
case .began:
// handle drag began
// I would stop the timer when drag begin
timer.invalidate()
case .moved:
// handle drag moved
// Update label's text for current playing time
case .ended:
// update the player's currTime and re-create the timer when drag is done.
player.currentTime = TimeInterval(slider.value)
timer = Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(updateTime(_:)), userInfo: nil, repeats: true)
default:
break
}
}
}