Android Fragment with ViewPager and SectionsPageAdapter method executed on user clicks tab name to display it or swipes to it

Question

I have been trying to determine why the onPause() and the onResume() methods were not fired when the user switches the the tab to be displayed when using a ViewPager and sectionsPageAdapter.

I assumed that when the user changes the tab being displayed, the onPause() or the onDestroy() methods would be called. Then, if the user returns to the tab, the onResume() method would be called, but it seems it is not the functionality...

is there any way to determine when the user switces a tab and to know to which tab it has been switched? Something like onFragmentBeingDisplayed() or similar.

Thanks!

EDIT: Answer from Suraj Vaishnav

By editing the constructor from the FragmentPageAdapter like this super(fm, FragmentPagerAdapter.BEHAVIOR_RESUME_ONLY_CURRENT_FRAGMENT); I could use the desired behaviour on the app

Answer 1

That's because ViewPager loads some fragments on the left side and on the right side of the current fragment. By default, ViewPager loads one on the left side and one on the right side of the fragment. You can change the number via: viewpager.setOfScreenPageLimit(int);

What you thinking is working exactly the same way in androidx's Fragment. Means onPause and onResume will call accordingly. So the first suggestion is to use androix. Check this answer: https://stackoverflow.com/a/57886441/7682257

For some reason, If you do not want to use androidx then in your Fragment, override setUserVisibleHint method, which gives you isVisibleToUser as a parameter.