处理textField中的非ASCII字符：shouldChangeCharactersInRange：replacementString： [英] Handling non-ascii characters in textField:shouldChangeCharactersInRange:replacementString:

问题描述

我试图防止中文（或其他所有非ASCII字符）被输入到UITextField。如在其他帖子中看到的，我实现了 textField：shouldChangeCharactersInRange：replacementString：，但是当我从在键盘顶部出现的word-list-thing按几个键， textField：shouldChangeCharactersInRange：replacementString：方法不会触发。

I'm trying to prevent Chinese (or otherwise, all non-ascii characters) from being input into a UITextField. As seen in other posts, I implemented textField:shouldChangeCharactersInRange:replacementString:, but when I enter Chinese words from the word-list-thing that appears on top of the keyboard after you press a few keys, the textField:shouldChangeCharactersInRange:replacementString: method does not fire.

任何想法？

推荐答案

使用：

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(textChanged:) name:UITextViewTextDidChangeNotification object:nil];

然后在您的函数中：

- (void)textChanged:(NSNotification *)notification{
  //remove observer
  [[NSNotificationCenter defaultCenter] removeObserver:self name:UITextViewTextDidChangeNotification object:nil];

  //change your textfield's value here e.g.
  myTextField.text = [MyUtils removeNonAsciiChar:myTextField.text];

  //add observer again
  [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(textChanged:) name:UITextViewTextDidChangeNotification object:nil];
}

注意，这是更昂贵的，因为你将每次更换整个字符串，但如果你不期望一个很长的字符串，它应该是好的。

Note however that this is more costly since you will be replacing the entire string everytime, but it should be okay if you're not expecting a very long string.

这篇关于处理textField中的非ASCII字符：shouldChangeCharactersInRange：replacementString：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！