Flex practice -- Demonstration of version2 in the online ordering system of pizza

In the Version1 version of pizza's online ordering system, our ordering process is very simple. We just ordered one at a time and made improvements in version2, during the ordering process, we allow the user to confirm the order quantity. when entering the order quantity, we initially set it to 1. At the same time, we also determine the user input format and only allow the user to enter numbers. User ordering process:

 

Finally, the key code for determining the order quantity format is attached: