Ios swift 3:如何添加UISlider?
我有Ios swift 3:如何添加UISlider?,ios,swift,slider,avaudioplayer,core-audio,Ios,Swift,Slider,Avaudioplayer,Core Audio,我有ViewController和AVAudioPlayer。现在我有了这个代码 import UIKit import AVFoundation var audioPlayer = AVAudioPlayer() class ViewController: UIViewController { @IBOutlet weak var slider: UISlider! @IBOutlet weak var playButton: UIButton! var index = 0 var ti
ViewController
和AVAudioPlayer
。现在我有了这个代码
import UIKit
import AVFoundation
var audioPlayer = AVAudioPlayer()
class ViewController: UIViewController {
@IBOutlet weak var slider: UISlider!
@IBOutlet weak var playButton: UIButton!
var index = 0
var timer: Timer?
override func viewDidLoad() {
super.viewDidLoad()
if index == 0{
let url = Bundle.main.url(forResource: "1", withExtension: "mp3")!
do {
audioPlayer = try AVAudioPlayer(contentsOf: url)
audioPlayer.prepareToPlay()
//audioPlayer.play()
//play(sender:AnyObject.self as AnyObject)
} catch let error {
print(error.localizedDescription)
}
}
}
@IBAction func slide(_ slider: UISlider) {
audioPlayer.currentTime = TimeInterval(slider.value)
}
@IBAction func play(sender: AnyObject) {
if !audioPlayer.isPlaying{
audioPlayer.play()
// **** The line below is the new line ****
timer = Timer(timeInterval: 1.0, target: self, selector: #selector(self.updateSlider), userInfo: nil, repeats: true)
RunLoop.main.add(timer!, forMode: .commonModes)
} else {
audioPlayer.pause()
playButton.setImage(UIImage(named: "pause.png"), for: UIControlState.normal)
timer?.invalidate()
}
}
func updateSlider(_ timer: Timer) {
slider.value = Float(audioPlayer.currentTime)
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
}
我想添加UISlider,通过音频文件更改拖动。如何操作?首先,您必须从滑块添加一个新的iAction,以确保在滑块值更改时通知您的类(在此处查找“响应用户交互”: 在此事件处理程序中,您必须设置音频当前时间
@IBAction func slide(_ slider: UISlider) {
audioPlayer.currentTime = TimeInterval(slider.value)
}
要确保滑块根据当前时间更新其值,必须在启动播放器时添加计时器,该播放器调用更新滑块值的自定义方法
@IBAction func play(sender: AnyObject) {
if !audioPlayer.isPlaying{
audioPlayer.play()
// **** The line below is the new line ****
timer = Timer(timeInterval: 1.0, target: self, selector: #selector(self.updateSlider), userInfo: nil, repeats: true)
RunLoop.main.add(timer, forMode: .commonModes)
} else {
audioPlayer.pause()
playButton.setImage(UIImage(named: "pause.png"), for: UIControlState.normal)
timer.invalidate()
}
}
之后,您必须创建更新滑块值的方法
func updateSlider(_ timer: Timer) {
slider.value = Float(audioPlayer.currentTime)
}
然后您必须设置滑块的最大值
override func viewDidLoad() {
super.viewDidLoad()
if index == 0{
let url = Bundle.main.url(forResource: "1", withExtension: "mp3")!
do {
audioPlayer = try AVAudioPlayer(contentsOf: url)
audioPlayer.prepareToPlay()
// **** These two lines below are new ****
slider.maximumValue = Float(audioPlayer.duration)
slider.value = 0.0
} catch let error {
print(error.localizedDescription)
}
}
}
最后,您必须在IBOutlets下面创建一个属性,用于保存计时器
var timer: Timer?
您想更改音量还是擦洗音频文件?@0x6368我想更改擦洗音频文件但要小心可能的保留周期,重复
定时器
会保留self
,而self
似乎会保留定时器
。invalidate()
应该会打破这个循环,但是在复制音频时离开屏幕可能需要一些清理。这是正常工作。但是,当我擦洗我的滑块是冻结。如何修复?编辑:我已经更新了的答案,将计时器
包含在运行循环常见模式中,以修复滚动时滑块的冻结。我有一个问题类“ViewController”没有初始值设定项
如何修复?我想你应该添加一个“?”到计时器:var timer:timer?
否则不允许为nil