This project must be done in Java. I use Android Studio. This program is a business situation.

This project needs to be a traditional shopping cart app for an online store. This will be a shopping cart that also handles inventory.

It will also change the inventory as user$$s shop and have the inventory change as the user selects items. It will have to be a database app to be able to do this. I would like to see a multiple table design of the system. To keep it simple we are only going to have size as a table holding a common detail. There should be an Inventory Table $($with ID$,$ Description, Price$),$ a Size Table $($with ID and SizeNumber$)$ and a table joining them InventorySizeinStock $($with ID$,$ InventoryTableID, SizeID, and QuantityInStock$)$ to hold the records.

Here is the current inventory for this online store

Red Shirt Price $$12$ Size $10($starting$)$ Quantity in Stock $6$

Red Shirt Price $$12$ Size $12($starting$)$ Quantity in Stock $4$

Red Shirt Price $$12$ Size $14($starting$)$ Quantity in Stock $3$

Blue Shirt Price $$14$ Size $10($starting$)$ Quantity in Stock $1$

Blue Shirt Price $$14$ Size $12($starting$)$ Quantity in Stock $3$

Blue Shirt Price $$14$ Size $14($starting$)$ Quantity in Stock $2$

Green Shirt Price $$16$ Size $10($starting$)$ Quantity in Stock $4$

Green Shirt Price $$14$ Size $12($starting$)$ Quantity in Stock $2$

Green Shirt Price $$14$Size $14($starting$)$ Quantity in Stock $1$

The app itself needs to be multi$-$screen and have controls allow the user to show by choosing a product $($like red shirt$)$ or to shop by size while choosing the size to shop by $($like size $12.)$

The second screen should show the product the user chose on the first screen to see here, and show the sizes to choose to add to their cart if they want. It should only show items in stock though, so if a previous person using this app had chosen the $1$ Blue Shirt size $10$ it should not show up here to choose at all. It should allow the user to select items and add them to their shopping cart. This screen should also have navigation tools to go back to the first screen or to go to their cart.

The second screen should show the products in the size the user chose on the first screen to see here $($so if they chose to shop by size and chose size $10$ then the red, blue, and green shirts in this one size should show on this screen$)$ and show these items to choose to add to their cart if they want. It should only show items in stock though, so if a previous person using this app had chosen the $1$ Blue Shirt size $10$ it should not show up here to choose at all. It should allow the user to select items and add them to their shopping cart. This screen should also have navigation tools to go back to the first screen or to go to their cart.

There should be a Shopping Cart Screen or Checkout Screen where there are controls to keep shopping $($and shows the first screen again$)$ or to checkout their order. It should also show what the current items in the shopping cart are and the current order total. If the user chooses to checkout their order it should change the database quantities down by the items being sold.