我需要在iPad上调整音量，使用了以下代码：
[[MPMusicPlayerController applicationMusicPlayer] setVolume:0];
但是这会改变音量并在iPad上显示系统音量条。 如何在不显示音量条的情况下更改声音？
我知道，setVolume:已经被弃用了，大家都说要使用MPVolumeView。如果这是解决我的问题的唯一方法，那么如何使用MPVolumeView更改音量呢？我没有看到MPVolumeView中任何可以更改音量的方法。
我应该与MPVolumeView一起使用其他类吗？
但最好使用MPMusicPlayerController。
谢谢您的建议！
在2018年，我们正在使用iOS 11.4系统。
您需要稍微延迟后更改slider.value。
extension MPVolumeView {
static func setVolume(_ volume: Float) {
let volumeView = MPVolumeView()
let slider = volumeView.subviews.first(where: { $0 is UISlider }) as? UISlider
DispatchQueue.main.asyncAfter(deadline: DispatchTime.now() + 0.01) {
slider?.value = volume
}
}
}
使用方法：
MPVolumeView.setVolume(0.5)
MPVolumeView时，就会出现此警告。目前看来，即使有这个警告，它仍然可以正常工作，并且没有人能够解决在这种情况下避免警告的问题。 - trungducDispatchQueue.main.asyncAfter？我重写了这个扩展程序而没有使用它，它仍然可以工作...除非我漏掉了什么。 - daspianistMPVolumeView UI对象。我猜异步等待是必要的，因为系统可能需要一段时间来初始化这个新对象。我建议在启动时只创建一次MPVolumeView - 然后随时使用它，无需等待和浪费电池。 - Robin StewartMPVolumeView有一个滑块，通过改变滑块的值，可以改变设备音量。我编写了一个MPVolumeView扩展，以便轻松访问滑块:
extension MPVolumeView {
var volumeSlider:UISlider {
self.showsRouteButton = false
self.showsVolumeSlider = false
self.hidden = true
var slider = UISlider()
for subview in self.subviews {
if subview.isKindOfClass(UISlider){
slider = subview as! UISlider
slider.continuous = false
(subview as! UISlider).value = AVAudioSession.sharedInstance().outputVolume
return slider
}
}
return slider
}
}
extension UIViewController {
func setVolumeStealthily(_ volume: Float) {
guard let view = viewIfLoaded else {
assertionFailure("The view must be loaded to set the volume with no UI")
return
}
let volumeView = MPVolumeView(frame: .zero)
guard let slider = volumeView.subviews.first(where: { $0 is UISlider }) as? UISlider else {
assertionFailure("Unable to find the slider")
return
}
volumeView.clipsToBounds = true
view.addSubview(volumeView)
DispatchQueue.main.asyncAfter(deadline: DispatchTime.now() + 0.1) { [weak slider, weak volumeView] in
slider?.setValue(volume, animated: false)
DispatchQueue.main.asyncAfter(deadline: DispatchTime.now() + 0.1) { [weak volumeView] in
volumeView?.removeFromSuperview()
}
}
}
}
使用方法：
// set volume to 50%
viewController.setVolume(0.5)
这里提供一个Swift的解决方案。可能有点靠不住，如果我发布后被苹果批准了，我会让你知道的。与此同时，这个方法对我来说完全有效：
Define an MPVolumeView and an optional UISlider in your View Controller
private let volumeView: MPVolumeView = MPVolumeView()
private var volumeSlider: UISlider?
In the storyboard, define a view that's hidden from the user (height=0 should do the trick), and set an outlet for it (we'll call it hiddenView here). This step is only good if you want NOT to display the volume HUD when changing the volume (see note below):
@IBOutlet weak var hiddenView: UIView!
In viewDidLoad() or somewhere init-y that runs once, catch the UISlider that actually controls the volume into the optional UISlider from step (1):
override func viewDidLoad() {
super.viewDidLoad()
...
hiddenView.addSubview(volumeView)
for view in volumeView.subviews {
if let vs = view as? UISlider {
volumeSlider = vs
break
}
}
}
When you want to set the volume in your code, just set volumeSlider?.value to be anywhere between 0.0 and 1.0, e.g. for increasing the volume:
func someFunc() {
if volumeSlider?.value < 0.99 {
volumeSlider?.value += 0.01
} else {
volumeSlider?.value = 1.0
}
}
重要提示： 这个解决方案将防止iPhone音量界面出现，无论是在您的代码中更改音量还是用户点击外部音量按钮时。如果确实希望显示音量界面，则跳过所有隐藏视图内容，并且不要将MPVolumeView添加为子视图。这会导致iOS在音量更改时显示音量界面。
Swift 5 / iOS 13
以下是我发现的最可靠的访问系统音量级别的方法。该方法基于其他答案，但不会浪费能源，也不需要异步等待。
在初始化期间（例如在viewDidLoad中），创建一个离屏的MPVolumeView：
var hiddenSystemVolumeSlider: UISlider!
override func viewDidLoad() {
let volumeView = MPVolumeView(frame: CGRect(x: -CGFloat.greatestFiniteMagnitude, y:0, width:0, height:0))
view.addSubview(volumeView)
hiddenSystemVolumeSlider = volumeView.subviews.first(where: { $0 is UISlider }) as? UISlider
}
然后使用隐藏的滑块，在需要时获取或设置系统音量：
var systemVolume:Float {
get {
return hiddenSystemVolumeSlider.value
}
set {
hiddenSystemVolumeSlider.value = newValue
}
}
我认为没有办法在不刷音量控制的情况下改变音量。你应该像这样使用MPVolumeView：
MPVolumeView* volumeView = [[MPVolumeView alloc] init];
// Get the Volume Slider
UISlider* volumeViewSlider = nil;
for (UIView *view in [volumeView subviews]){
if ([view.class.description isEqualToString:@"MPVolumeSlider"]){
volumeViewSlider = (UISlider*)view;
break;
}
}
// Fake the volume setting
[volumeViewSlider setValue:1.0f animated:YES];
[volumeViewSlider sendActionsForControlEvents:UIControlEventTouchUpInside];
@udjat在Swift 3中的回答
extension MPVolumeView {
var volumeSlider: UISlider? {
showsRouteButton = false
showsVolumeSlider = false
isHidden = true
for subview in subviews where subview is UISlider {
let slider = subview as! UISlider
slider.isContinuous = false
slider.value = AVAudioSession.sharedInstance().outputVolume
return slider
}
return nil
}
}
版本：Swift 3 和 Xcode 8.1
extension MPVolumeView {
var volumeSlider:UISlider { // hacking for changing volume by programing
var slider = UISlider()
for subview in self.subviews {
if subview is UISlider {
slider = subview as! UISlider
slider.isContinuous = false
(subview as! UISlider).value = AVAudioSession.sharedInstance().outputVolume
return slider
}
}
return slider
}
}
self.volumeSlider.value = 1 // 获取最大音量
顺便说一下，self表示MPVolumeView实例。希望能帮到你。 - Jeromeimport UIKit
import MediaPlayer
class UIVolumeSlider: UISlider {
private let keyVolume = "outputVolume"
func activate(){
updatePositionForSystemVolume()
guard let view = superview else { return }
let volumeView = MPVolumeView(frame: .zero)
volumeView.alpha = 0.000001
view.addSubview(volumeView)
try? AVAudioSession.sharedInstance().setActive(true, options: .notifyOthersOnDeactivation)
AVAudioSession.sharedInstance().addObserver(self, forKeyPath: keyVolume, options: .new, context: nil)
addTarget(self, action: #selector(valueChanged), for: .valueChanged)
}
func deactivate(){
AVAudioSession.sharedInstance().removeObserver(self, forKeyPath: keyVolume)
removeTarget(self, action: nil, for: .valueChanged)
superview?.subviews.first(where: {$0 is MPVolumeView})?.removeFromSuperview()
}
func updatePositionForSystemVolume(){
try? AVAudioSession.sharedInstance().setActive(true, options: .notifyOthersOnDeactivation)
value = AVAudioSession.sharedInstance().outputVolume
}
override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
if keyPath == keyVolume, let newVal = change?[.newKey] as? Float {
setValue(newVal, animated: true)
}
}
@objc private func valueChanged(){
guard let superview = superview else {return}
guard let volumeView = superview.subviews.first(where: {$0 is MPVolumeView}) as? MPVolumeView else { return }
guard let slider = volumeView.subviews.first(where: { $0 is UISlider }) as? UISlider else { return }
DispatchQueue.main.asyncAfter(deadline: DispatchTime.now() + 0.01) {
slider.value = self.value
}
}
}
@IBOutlet private var volumeSlider:UIVolumeSlider!
volumeSlider.updatePositionForSystemVolume()
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
volumeSlider.activate()
}
override func viewWillDisappear(_ animated: Bool) {
volumeSlider.deactivate()
super.viewWillDisappear(animated)
}
MediaPlayer 使用 AVPlayer）等等。 - Gargo import MediaPlayer
class CusomViewCOntroller: UIViewController
// could be IBOutlet
var customSlider = UISlider()
// in code
var systemSlider = UISlider()
override func viewDidLoad() {
super.viewDidLoad()
let volumeView = MPVolumeView()
if let view = volumeView.subviews.first as? UISlider{
systemSlider = view
}
}
接下来在代码中写入：
systemSlider.value = customSlide.value