key-value-observing

问题 I have a cell that takes up the entire screen so there is only 1 visible cell at a time. Inside the cell I have an AVPlayer. Inside the cell's parent vc I have a KVO observer that listens to the "timeControlStatus" . When the player stops playing I call a function stopVideo() inside the cell to stop the player and either show a replay button or a play button etc. 3 problems: 1- When the video stops/reaches end if I don't use DispatchQueue inside the KVO the app crashes when the cell's

问题 I have a cell that takes up the entire screen so there is only 1 visible cell at a time. Inside the cell I have an AVPlayer. Inside the cell's parent vc I have a KVO observer that listens to the "timeControlStatus" . When the player stops playing I call a function stopVideo() inside the cell to stop the player and either show a replay button or a play button etc. 3 problems: 1- When the video stops/reaches end if I don't use DispatchQueue inside the KVO the app crashes when the cell's

问题 I have a cell that takes up the entire screen so there is only 1 visible cell at a time. Inside the cell I have an AVPlayer. Inside the cell's parent vc I have a KVO observer that listens to the "timeControlStatus" . When the player stops playing I call a function stopVideo() inside the cell to stop the player and either show a replay button or a play button etc. 3 problems: 1- When the video stops/reaches end if I don't use DispatchQueue inside the KVO the app crashes when the cell's

来源： https://stackoverflow.com/questions/44827613/how-can-i-use-key-value-observing-with-smart-keypaths-in-swift-4

来源： https://stackoverflow.com/questions/44827613/how-can-i-use-key-value-observing-with-smart-keypaths-in-swift-4

问题 I am having trouble with the new observe API in Swift 4. player = AVPlayer() player?.observe(\.currentItem.status, options: [.new], changeHandler: { [weak self] (player, newValue) in if let status = AVPlayer.Status(rawValue: (newValue as! NSNumber).intValue) { } } But I get an error Type of expression is ambiguous without more context. How do I fix it? Not sure about keyPath syntax. There is also a warning in extracting AVPlayerStatus in the closure above Cast from 'NSKeyValueObservedChange'

问题 For the life of me I can't get KVO working with UISwitch. I have a custom UITableViewCell with a UISwitch added through Interface Builder. I created an IBOutlet for the UISwitch and linked it to theSwitch variable. - (id)initWithCoder:(NSCoder *)coder { self = [super initWithCoder:coder]; if (self) { [theSwitch addObserver:self forKeyPath:@"on" options:NSKeyValueObservingOptionNew context:NULL]; } return self; } - (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:

问题 For the life of me I can't get KVO working with UISwitch. I have a custom UITableViewCell with a UISwitch added through Interface Builder. I created an IBOutlet for the UISwitch and linked it to theSwitch variable. - (id)initWithCoder:(NSCoder *)coder { self = [super initWithCoder:coder]; if (self) { [theSwitch addObserver:self forKeyPath:@"on" options:NSKeyValueObservingOptionNew context:NULL]; } return self; } - (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:

问题 For the life of me I can't get KVO working with UISwitch. I have a custom UITableViewCell with a UISwitch added through Interface Builder. I created an IBOutlet for the UISwitch and linked it to theSwitch variable. - (id)initWithCoder:(NSCoder *)coder { self = [super initWithCoder:coder]; if (self) { [theSwitch addObserver:self forKeyPath:@"on" options:NSKeyValueObservingOptionNew context:NULL]; } return self; } - (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:

问题 For the life of me I can't get KVO working with UISwitch. I have a custom UITableViewCell with a UISwitch added through Interface Builder. I created an IBOutlet for the UISwitch and linked it to theSwitch variable. - (id)initWithCoder:(NSCoder *)coder { self = [super initWithCoder:coder]; if (self) { [theSwitch addObserver:self forKeyPath:@"on" options:NSKeyValueObservingOptionNew context:NULL]; } return self; } - (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change: