为什么AVAsset的状态更改观察者不起作用? [英] Why does observer for status change of AVAsset not work?
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问题描述
我实现了以下来自苹果的代码.它旨在观察playerItem状态的变化.问题是由于某种原因它不起作用.准备就绪后,观察功能将无法运行.
I implemented the following code from Apple. It is meant to observe for a change in the status of a playerItem. The problem is that for some reason it does not work. The observe function does not run when ready.
所有相关代码如下:
func preloadVideo(media: Media) {
//setup code, and then:
media.playerItem1!.addObserver(self,
forKeyPath: #keyPath(AVPlayerItem.status),
options: [.old, .new],
context: &playerItemContext)
}
观察方法:
private var playerItemContext = 0
override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
// Only handle observations for the playerItemContext
print("jdslfhjkfdhaldfahjkflhajfldashkjfdshkjlas")
guard context == &playerItemContext else {
super.observeValue(forKeyPath: keyPath, of: object,change: change, context: context)
return
}
if keyPath == #keyPath(AVPlayerItem.status) {
let status: AVPlayerItem.Status
// Get the status change from the change dictionary
if let statusNumber = change?[.newKey] as? NSNumber {
status = AVPlayerItem.Status(rawValue: statusNumber.intValue)!
} else {
status = .unknown
}
print("dsfdgddgdggdgdgdgddsafdsaf434fdfdg433444343")
// Switch over the status
switch status {
case .readyToPlay:
//Stop animation, and go to p3
print("dsfdsafdsaf434433444343")
if goToVideo {
print("Runinfdsh sahkbdsfhbsadfbadsfl")
goToP3()
}
break
// Player item is ready to play.
case .failed: break
// Player item failed. See error.
case .unknown: break
// Player item is not yet ready.
@unknown default: break
//fatal error
}
}
}
此方法将首先运行:
@objc func viewHandleTap(_ sender: UITapGestureRecognizer) {
if selectedPost?.interimMedia.first?.imageURLString != nil || selectedPost?.interimMedia.first!.playerQueue?.status.rawValue == 1 {
//do something
} else {
//status is 0 (video has not loaded yet)//load animation
//this runs...
goToVideo = true
}
}
我如何使其起作用?目前,观察方法中没有任何东西可以打印.
How can I make it work? Currently nothing in the observe method is printing.
如果还有另一种方法可以完成此操作,然后发布答案.
If there is another method to accomplish this go ahead and post as answer.
推荐答案
尝试将addObserver选项更新为[.old,.new,.initial,.prior].
Try by updating addObserver options to [.old, .new, .initial, .prior].
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