iPhone限制用户在文本字段中输入空格

Question

我想限制用户在UITextField中输入空格.为此我使用此代码

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
    if ( string == @" " ){
        UIAlertView *error = [[UIAlertView alloc] initWithTitle:@"Error" message:@"You have entered wrong input" delegate:self cancelButtonTitle:nil otherButtonTitles:@"OK", nil];
        [error show];
        return NO;
    }
    else {
        return YES;
    }
}

但它没有用......它有什么问题？

Answer 1

问题是

string == @" "

是错的.字符串的平等使用:

[string isEqualToString:@" "]

:).

Answer 2

这将搜索您的替换字符串是否包含空格,如果是,则它会抛出错误消息,如果不是,则返回YES.

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string 
{
    NSRange spaceRange = [string rangeOfString:@" "];
    if (spaceRange.location != NSNotFound)
    {
        UIAlertView *error = [[UIAlertView alloc] initWithTitle:@"Error" message:@"You have entered wrong input" delegate:self cancelButtonTitle:nil otherButtonTitles:@"OK", nil];
        [error show];
        return NO;
    } else {
        return YES;
    }
}