iOS WatchKit - 将键值观察器添加到 NSUserDefaults 崩溃

Question

我正在尝试添加从 iPhone 向 Watch 发送数据的功能。我已经设置了应用程序组并且一切运行顺利，但是当我尝试将观察者添加到 Watch Extension 文件中的 NSUserDefaults 时，应用程序总是在启动时崩溃。(是的，我已验证应用组名称正确并检查了所有目标功能，并且所有配置文件都是最新的并启用了应用组)

代码:

override func willActivate() 
{
    super.willActivate()

    NSUserDefaults(suiteName: "my.suite.name")?.addObserver(self, forKeyPath: "phoneSaysHello", options: NSKeyValueObservingOptions.New, context: nil)
}

override func didDeactivate() 
{
    super.didDeactivate()

    // Remove listener for commands sent from phone
    NSUserDefaults(suiteName: "my.suite.name")?.removeObserver(self, forKeyPath: "phoneSaysHello", context: nil)
}

错误:

*** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'An instance 0x7f99534559b0 of class NSUserDefaults was deallocated while key value observers were still registered with it. Current observation info: ( Context: 0x0, Property: 0x7f9953609200> )'

Answer 1

看起来你的 NSUserDefaults 已经超出了范围。将 userDefaults 转换为实例变量应该会停止抛出异常。