使用KVO更改属性时发送通知 [英] Send Notification When a Property is Changed Using KVO

问题描述

我的课程中有一个名为 myName 的属性，例如：

I had a property named myName in my class, like:

@property (nonatomic, strong) NSString *myName;

我需要在 myName 属性值已更改。

I need to send a notification when the myName property's value is changed.

现在我正在做类似的事情：

Now I'm doing something like:

- (void)setMyName:(NSString *)name
{
  _myName = name;
  [[NSNotificationCenter defaultCenter] postNotificationName:CHANGE_NOTIFICATION object:nil];
}

我知道有类似 键值观察 。但我不知道如何实现它，我阅读了整个文档，但无法理解。

I know there is something like Key-Value Observing in iOS. But I don't know how to implement it, I read the entire document, but couldn't get a good understanding.

请帮助我理解如何实现相同而不使用自定义setter。

Please help me to understand how to implement the same without using custom setter.

推荐答案

试试这个：

MyClass *var = [MyClass new];
[var addObserver:self forKeyPath:@"myName" options:NSKeyValueChangeOldKey context:nil];

并实施

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
{

}

当myName属性发生变化时，将随时调用此方法

this method will be called anytime when myName property changes

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