Pages and frames
The page navigation model is a hub and spoke system. This means that unless you explicitly add links to other pages within your app, users must use the Back button to navigate back to a page that they viewed. This is similar to how a web browser displays and navigates webpage history.
The system tracks each page that a user has visited and places it in what is called the back stack so that when a user pushes the Back button, the last saved page in the back stack is served. There’s no limit to the number of pages that can be placed in the back stack.
For example, this means that a user navigating from page 1 (p1) to page 2 (p2) to p1 to p2 to page 3 (p3) to p1 creates a back stack of p1, p2, p1, p2, p3, p1. If the user modified content in the second instance of p2 in the back stack, but navigates back using the Back button to the first instance of p2 in the back stack, previous changes don’t appear on that page unless the page refreshes the data; the view is a snapshot of how the user saw that page at that point in navigatio