iOS UITextField 禁止输入空格

-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string{

NSString *temp = [[string componentsSeparatedByCharactersInSet:[NSCharacterSet whitespaceCharacterSet]]componentsJoinedByString:@""];
if (![string isEqualToString:temp]) {
    return NO;
    
}
return YES;
}