正常号转银行卡号 － 增加4位间的空格

-(NSString *)normalNumToBankNum:(NSString*)number
{
    NSString *tmpStr = number;
    
    NSInteger size = (tmpStr.length / 4);
    
    NSMutableArray *tmpStrArr = [[NSMutableArray alloc] init];
    for (int n = 0;n < size; n++)
    {
        [tmpStrArr addObject:[tmpStr substringWithRange:NSMakeRange(n*4, 4)]];
    }
    
    [tmpStrArr addObject:[tmpStr substringWithRange:NSMakeRange(size*4, (tmpStr.length % 4))]];
    
    tmpStr = [tmpStrArr componentsJoinedByString:@" "];
    
    return tmpStr;
}

输入框每4位加一个空格

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
    
    if (textField == numTF) {
        //只允许数字输入
        NSUInteger lengthOfString = string.length;
        for (NSInteger loopIndex = 0; loopIndex < lengthOfString; loopIndex++) {//只允许数字输入
            unichar character = [string characterAtIndex:loopIndex];
            if (character < 48) return NO; // 48 unichar for 0
            if (character > 57) return NO; // 57 unichar for 9
        }
        
       // 四位加一个空格
       NSString *temp = [textField.text stringByReplacingCharactersInRange:range withString:string];
        if ([string isEqualToString:@""]) { // 删除字符
            if ((textField.text.length - 2) % 5 == 0) {
                textField.text = [textField.text substringToIndex:textField.text.length - 1];
            }
            return YES;
        } else {
            if (textField.text.length % 5 == 0) {
                textField.text = [NSString stringWithFormat:@"%@ ", textField.text];
                if (temp.length > 25) {
                    textField.text = [temp substringToIndex:25];
                    [self.view.window makeToast:@"最多25个字符"];
                    return NO;
                }else{
                    return YES;
                }
            }
        }
        
        return YES;
}
}