在Objective c中的Button Action中执行一次计算

Question

我有一个按钮，其中我正在做一些乘法和除法并将该值传递给另一个VC。每当按下按钮时，计算再次发生，并再次递增n值。我希望每当执行按钮操作时都应该进行一次计算。我通过另一个VC中的NSUserdefault传递值。我的代码是这样的，

 paymentTotal = (grandTotal /100) * 2.5 + 0.20;
                    grandTotal = grandTotal + paymentTotal;
                   self.lblGrandTotal.text = [NSString stringWithFormat:@"£%.2f", grandTotal];
                    NSLog(@"Total: %@",self.lblGrandTotal.text);
                    NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];
                    // saving an NSString
                    [prefs setObject:self.lblGrandTotal.text forKey:@"GrandTotal"];
                    NSLog(@"Save_Order_Data: %@", self.save_order_data);
                    CardExampleViewController *exampleVC = [CardExampleViewController new];
                    exampleVC.delegate = self;
                    exampleVC.save_order_data = self.save_order_data;
                    [self.navigationController pushViewController:exampleVC animated:YES];

Answer 1

你可以试试

  if(paymentTotal != 0)
  {
      paymentTotal = (grandTotal /100) * 2.5 + 0.20;
      grandTotal = grandTotal + paymentTotal;
  }