NSUnknownKeyException:被发送到与“播放器"不兼容的KVC的对象.财产 [英] NSUnknownKeyException : was sent to an object that is not KVC-compliant for the "player" property

问题描述

我已将代码更新为在Xcode 9中快速运行4.在此之前，它可以正常工作.但是现在AVplayer崩溃了，下面是崩溃的代码.

I have updated my code to swift 4 in Xcode 9. Before that it was working fine. But now AVplayer is crashing at observers below is the code where it is crashing.

addObserver(self, forKeyPath: "player.currentItem.duration", options: [.new, .initial], context: &playerViewControllerKVOContext)

日志是

由于未捕获的异常而终止应用程序 'NSUnknownKeyException'，原因:'[addObserver:forKeyPath:@"player.currentItem.duration"选项:5 context:0x10ff74ac8]已发送到不符合KVC的对象 玩家"属性."

Terminating app due to uncaught exception 'NSUnknownKeyException',reason: '[ addObserver: forKeyPath:@"player.currentItem.duration" options:5 context:0x10ff74ac8] was sent to an object that is not KVC-compliant for the "player" property.'

推荐答案

Swift没有自己的键值观察器，因此对于Swift 4，我们必须添加:

Swift does not have the Key value observer of its own so for Swift 4 we have to add:

@objc dynamic

位于需要观察其值的属性之前.在您的情况下，它将是AVPlayer实例.例如:

before the property whose value you need to observe. In your case it will be the AVPlayer instance. e.g.:

class MyPlayerCustomView: UIView {

@objc dynamic var myPlayer: AVPlayer?

}

希望这可以解决您的问题.它确实解决了我的问题！

Hope this solves your problem. It did solve mine!

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