键值观察和NSButton状态 [英] Key Value Observing and NSButton state

问题描述

我正在尝试观察复选框状态，并在复选框状态更改时在应用程序中进行适当的更改.在使用复选框管理窗口的窗口管理器中，我具有以下观察者设置:

I'm trying to observe checkbox status and make appropriate changes in the app when checkbox status changes. In a window manager that manages the window with checkbox I have following observer setup:

- (void)awakeFromNib
{
  [myCheckBox addObserver:self 
                  forKeyPath:@"state" 
                     options:(NSKeyValueObservingOptionNew | NSKeyValueObservingOptionOld) 
                     context:NULL];
}

- (void)dealloc
{
  [myCheckBox removeObserver:self forKeyPath:@"state"];
}

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
{
  NSLog(@"KeyPath: %@", keyPath);
  NSLog(@"ofObject: %@", object);
  NSLog(@"change: %@", change);
}

我还已经将myCheckBox连接到文件所有者(这是窗口控制器)并连接到窗口中的相应复选框.但是，当我运行我的应用程序时，永远不会调用observeValueForKeyPath:ofObject:change:context:方法.

I also have wired up myCheckBox to file owner (which is window controller) to appropriate checkbox in the window. However when I run my app observeValueForKeyPath:ofObject:change:context: method is never called.

我在做什么错了?

推荐答案

在-awakeFromNib中，检查myCheckbox不是零.如果为零，则说明它在IB中未正确连接.

In -awakeFromNib check that myCheckbox is not nil. If it's nil then it's not connected properly in IB.

正确的密钥路径是"cell.state".

The correct keypath is "cell.state".

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