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。为此我使用这段代码

- (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;
    }
}

但它不工作....它有什么问题？

Answer 1

问题是

string == @" "

错了。字符串的相等性使用:

[string isEqualToString:@" "]

:).