Creating the Attachment Pager

Having modularized the category picker, it's time to turn your attention to the attachments. When you implemented the file selection, you left a Toast in place to show where the code would normally attach the selected file to the ClaimItem being captured. This next stage will be to create a Fragment that will encapsulate the previewing of the Attachment objects. You'll also move much of the attachment logic into this Fragment. Although the code to connect to other applications and request permissions is commonly placed in an Activity class, Fragment classes are also capable of performing the same actions, and the attachment pager is a perfect opportunity to show this off.

This Fragment will show a pattern where the Fragment interacts with the Activity that it belongs to without directly sending events upward. The instinct of most developers when encountering a Fragment for the first time is to use the pattern in the template where the Fragment can send events...