Android 9 Development Cookbook - Third Edition

Passing data between Fragments

Often, the need arises to pass information between Fragments. An email application serves as a classic example. It's common to have the list of emails in one Fragment and show the email details in another Fragment (this is commonly referred to as a Master/Detail pattern). Fragments make creating this pattern easier because we only have to code each Fragment once, then include them in different layouts. We can easily have a single Fragment in a portrait layout with the ability to swap out the master Fragment with the detail Fragment when an email is selected. We can also create a two-panel layout where both the list and detail Fragments are side by side. Either way, when the user clicks the email in the list, ...