Only a few lines of iOS code limit TextField input length

There are many methods for restricting the input length of textField on the Internet, but I don’t think it is perfect. To be precise, it does not meet the actual development requirements. Therefore, here I will sort out the method for restricting the input length of textField.

What I am using is not the listening method but the most different proxy implementation method. Why not use listening???
When you see this article, you may be troubled by one thing, that is, you cannot perfectly control the input content after using monitoring to limit the input length.

Give a simple example:

You need to limit the input length to 30 characters. When you enter 30 characters, you can really control it well to prevent you from continuing to input, but the problem also comes. When you move the cursor to the middle of the input content, you can continue to input this kind of input is very distressing because when you enter, your cursor will move to the end and restrict you from continuing to input, but the Neirong you just entered is retained in the middle of the text, which is not in line with the requirements.

Therefore, using a proxy here can achieve the effect we want well, and only a few lines of code hope to help you.

 - (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
  
  if (textField == ) {
  //In order to obtain the delete operation in the if time here, if there is no such thing as the delete key will not be used after the word limit is reached.    if ( == 1 &&  == 0) {
      return YES;
    }
    //so easy
    else if ( >= 30) {
       = [ substringToIndex:30];
      return NO;
    }
  }
  return YES;
}

The above is all the content of this article. I hope it will be helpful to everyone's study and I hope everyone will support me more.