How to using Idling Resource for multiple activities

I am new to android UI testing. I have `3 Activities(A,B,C)` in my project. `Activity A` has one button, on click of the button I open `B Activity` which has an `EditText` and a `Button`. On filling some text and click on the button it makes a network call and `onSuccess` goes to `Activity C`. In `Activity C` I make one more network call and `onSuccess` I show a Toast. How to test the flow from `Activity A to C` by waiting for the networks to complete ?

The issue does not name a sample, source file, or existing test. Start by locating the Android UI-testing samples and their tests for activity navigation and network synchronization, then determine whether the requested guidance belongs in an existing sample or its documentation. Done means the A-to-C flow and both network waits have a documented, reproducible testing approach.

Written by the indexing model from the issue text.