我的片段不会同时创建

Question

I really don't get it.

Here is my situation :

I have one activity and three fragments. My fragments are organised with ViewPager, so I can swipe between them easily (horizontaly) :

Fragment 1 (main, left) - Fragment 2 (middle) - Fragment 3 (right)

When I launch my app. I'm at Fragment 1 (left), and when I read my Logcat, it's indicated that my Fragment 1 and Fragment 2 has been created and onResume() has been called (for both of them). But not the Fragment 3. So, I swipe to the right (to go at the Fragment 2) and only at this moment I can read : onCreateView() Fragment 3 and onResume() Fragment 3

I go back to Fragment 2 and it says : onResume() Fragment 1 . And I go back to the Fragment 1 (Left), and It says : onPause() Fragment 3

Another weird thing : My fragment 2 (middle) absolutely never calls onPause() or onResume() except when I leave the application...

It makes no sense right ?

EDIT

I followed this tutorial to realise my pageviewer : https://www.javacodegeeks.com/2013/04/android-tutorial-using-the-viewpager.html

EDIT 2

When I display ScanFragment scanfragment = (ScanFragment) getSupportFragmentManager().getFragments().get(0); it returns me "Fragment 1", but after few swipes, it returnes me "Fragment 2"

Does someone understands ?

Answer 1

This is is the expected behaviour of ViewPager. It will only create views/fragments when required. Here you can read more about ViewPager .