限制uitextview中的字符数 [英] Limit number of characters in uitextview

问题描述

我提供了一个文本视图来推特一些字符串。

我正在应用以下方法将字符数限制为140个。

   - （BOOL）textView：（UITextView *）textView shouldChangeTextInRange：（NSRange）range replacementText：（NSString *）text {
 
 
 if（[text isEqualToString：@\ b]）{
 DLog（@Ohoooo）; 
返回YES; 
}否则if（[[textView text] length]> 140）{
 
返回NO; 
} 
 
返回YES; 
} 
  

除了退格不起作用的第一个条件外，代码运行良好。
假设我已达到140个字符的限制，因此该方法将给我假，用户无法插入更多字符，但在此之后，当我尝试删除某些字符时，文本视图的行为与禁用时一样。 / p>

那么问题是如何从 textview.text 中删除​​字符或重新启用文本视图。

解决方案

你应该寻找一个空字符串，作为 apple reference 说

如果用户按下Delete键，则范围的长度为1，空字符串对象将替换该单个字符。

I认为你实际想要的支票是 [[textView text] length] - range.length + text.length> 140 ，用于计算剪切/粘贴操作。

I am giving a text view to tweet some string .

I am applying the following method to restrict the number of characters to 140 in length.

- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text{


    if([text isEqualToString:@"\b"]){
        DLog(@"Ohoooo");
        return YES;
    }else if([[textView text] length] > 140){

        return NO;
    }

    return YES;
}

The code is working nicely except the first condition that backspace is not working. suppose that I have reached the limit of 140 characters so that the method will give me false and the user can not insert more characters but after that when I try to delete some characters the text view behave as it is disabled .

So the question how do delete characters from textview.text or re-enable the text view .

解决方案

You should be looking for an empty string instead, as the apple reference says

If the user presses the Delete key, the length of the range is 1 and an empty string object replaces that single character.

I think the check you actually want to make is something like [[textView text] length] - range.length + text.length > 140, to account for cut/paste operations.

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