#pragma mark - tf代理
-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string{
    if (self.step==1) {
        if (textField == self.mobileOrNameView.tf) {
            if (textField.text.length>=11&&string.length>0) {
                return NO;
            }
            return YES;
            
        }else if (textField == self.codeOrIDCardNumView.tf){
            if (textField.text.length>=6&&string.length>0) {
                return NO;
            }
            return YES;
        }
    }else if (self.step == 2){
        //姓名 身份证号
        if (textField == self.mobileOrNameView.tf) {
            return YES;
            
        }else if (textField == self.codeOrIDCardNumView.tf){
            if (textField.text.length==18&&!([string isEqualToString:@"x"]||[string isEqualToString:@"X"]||[string isEqualToString:@""])) {
                return NO;
            }else if (textField.text.length==17&&([string isEqualToString:@"➒"])){
                return YES;
            }else if (textField.text.length==18&&([string isEqualToString:@"x"]||[string isEqualToString:@"X"])){
                return YES;
            }
        }
    }
    return YES;
}