If you are using the iOS 12+ version on your device, you can add products to your lists in the Buy Me a Pie! app via Siri by adding a shortcut.
Open the Shortcuts app on your iOS-based device and tap "Create Shortcut":
Tap "Add Action":
Tap "Apps" and choose the Buy Me a Pie! app:
Choose the action "Add New Product":
You can specify a product name (or product names) if you would like to add it (or them) each time you launch the shortcut or leave the field blank if you would prefer Siri to ask you which product to add.
Tap "Show more" if you would like to specify the list name:
And tap "Choose" to choose a shopping list:
Please, note that if there are no lists in your Buy Me a Pie! app, you will not be able to choose a list and, therefore, products will not be added. So, you have to create at least one list in the app first.
You can choose one of your lists if you would like products to be added to the same list each time you launch the shortcut or you can select "Ask each time" or leave the field blank if you prefer Siri to ask you which list to use.
Add a name to the shortcut (for example, "Buy Me a Pie"). From now on, once you tell Siri this name, the shortcut will be automatically launched:
You can also add a set of related actions to the shortcut. Tap the "+" symbol to add a new action, select "Apps" and the Buy Me a Pie! app and then tap "Add New Product".
Let us suppose that we would like to add 2 different products to the same list with the help of a shortcut. Tap "Show more" in the second action and then "Choose" to choose a shopping list. In order to use the same list as in the first action, tap "Select Magic Variable":
Tap "Current List":
As a result, the second product will be added to the same list as the first one: