即使UITextField为空，我还能检测到删除键吗？ [英] Can I detect the delete key even if the UITextField is empty?
问题描述
当UITextField什么都不包含时，按键盘的删除键不会调用任何UITextFieldDelegate的方法。
When UITextField contains nothing, pressing the delete key of keyboard won't call any of UITextFieldDelegate's methods.
如何检测它？
编辑：
似乎没有琐碎的方法来做到这一点。我能找到的最有用的链接是：
There seems no trivial way to do it. The most useful links I can find are:
How to get the actual key pressed in a UITextField
简而言之，我的解决方案是在文本字段的开头放置一个永久的SPACE。并进行其他必要的更改（textFieldShouldReturn：，textField：shouldChangeCharactersInRange：replacementString：等。）。
In short, my solution is to put a permanent SPACE at the start of the text field. And make other nesessary changes(textFieldShouldReturn:, textField:shouldChangeCharactersInRange:replacementString:, etc.).
推荐答案
可以放一个按钮在它上面，但是有点脆弱，因为键盘布局可能会随着不同的iOS版本而改变，并且肯定有不同语言的不同键盘布局。
Its possible to put a button over it, but that's a bit fragile since keyboard layout could change with different iOS versions and there certainly are different keyboard layouts for different languages.
查看管理文本字段和文本视图Apple文档。我确定有办法做到这一点。它类似于UITextField实现了一个获取keyevents的协议。其中一个关键事件可能是删除键，因此您可以覆盖接收这些键的任何方法并以此方式获取。
Look at the "Managing Text Fields and Text Views" Apple doc. Im sure there is a way to do this. Its something like a UITextField implements a protocol to get keyevents. One of those key events will probably be a delete key, so you could override whatever method receives these and get it that way.
这篇关于即使UITextField为空，我还能检测到删除键吗？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
