我怎样才能检测的UITextField按键事件? [英] How can I detect a KeyPress event in UITextField?
问题描述
在的UITextView
有一个更改事件来处理按键。然而,的UITextField
还没有这样的事件。
In UITextView
there is a Changed event to handle keypress. However the UITextField
has not such event.
我怎样才能检测的UITextField
?
有一个方法,这里介绍 使用通知,但我有问题是,我不能从TextFieldTextDidChangeNotification退订。
There is a method described here using notifications, however the problem I have is that I cannot unsubscribe from the TextFieldTextDidChangeNotification.
推荐答案
我不知道这是你的问题。你好像是第一个回答自己,即
解决方案(从你的链接)是使用 NSNotificationCenter.DefaultCenter.AddObserver
。
I'm not sure which is your question. The first one you seem to have answered yourself, i.e.
the solution (from your link) is to use NSNotificationCenter.DefaultCenter.AddObserver
.
二是有关的退订的 - 如果你想停下来观察你应该调用以前的方法对应,即 NSNotificationCenter.DefaultCenter.RemoveObserver
。
The second is about unsubscribing - if you want to stop observing you should call the previous method counterpart, i.e. NSNotificationCenter.DefaultCenter.RemoveObserver
.
只要保持对象从的addObserver
返回,所以你可以把它提供给 RemoveObserver 。code>
Just keep the object returned from AddObserver
so you can supply it to RemoveObserver
.
注意::如果我没有正确理解你的问题,请使用修改并添加你想要什么的一些细节和/或代码来实现,我们会尽我们最大的努力帮助: - )
note: If I did not understand your question correctly please use edit and add some details and/or code of what you want to achieve and we'll do our best to help :-)
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