Navigation Component Playground

This is a sample project where I experimented with different aspects of the Android Navigation Component.

What's implemented?

• single Activity with Fragments
• navigation graph in XML
• handling of notifications (explicit deep links)
• custom handling of implicit deep links (more on that later)
• passing arguments between Fragments via Safe Args
• starting Fragments for result and waiting for that result (similar to Activity's startActivityForResult and onActivityResult)
• transitions between fragments with shared Toolbar
• a simple Toolbar navigation icon morphing ("<-" -> "X")
• base Dagger setup with a FragmentFactory used to create Fragments with non-default constructors

There's no MVP/MVVM/MVI here - just the Navigation Component to make the sample simple.

How does it look like?

App

Graph

What's custom in deep link handling?

Normally deep links would clear the entire back stack and start fresh. There are some differences between explicit and implicit deep links as well whether Intent.FLAG_ACTIVITY_NEW_TASK was provided or not.

In the sample app, regardless of Intent.FLAG_ACTIVITY_NEW_TASK I wanted to show the Fragment on top of the existing stack if the app was in the background or and start a new stack only if it was killed.

Also, this deep link when opened would pop specific Fragments from the back stack.

Handling Fragments results

My approach is based on Using Navigation Architecture Component in a large banking app article with some tweaks added to be able to pop the back stack further than the previous screen e.g. 2 screens back.

In the sample app this happens when e.g. we have the following stack:

Offer Fragment --> Collective login Fragment -> Login with password Fragment

Now, what we would like to do is go back to Offer Fragment and in there handle this result and e.g. start Apply Fragment.