How to using Idling Resource for multiple activities

[SAGARSURI]

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 ?