When should a Fragment's onActivityCreated be called?

Question

I have a few Fragments in a ViewPager, and I've found the Fragment's onActivityCreated and onCreateView are both being called on the page before I expect.

For example, when the ViewPager transitions from page 2 to 3, then the Fragment at page 4's onCreateView and onActivityCreated are being called.

I'm intending to initiate a network request in onActivityCreated but it is starting one screen too soon. According to the Android docs , onActivityCreated is called "when the fragment's activity has been created and this fragment's view hierarchy instantiated." which leads me to believe I'm using the method correctly.

Answer 1

For smooth loading of data view pager will load the fragments in advance. 1. If you are at 1st position(first fragment),so its automatically loads the next 2 fragments 2.Or if you are at 2 or later,then it will load previous one fragment and next fragment

Answer 2

ViewPager loads the next fragment for smooth transition between fragments, and that's why your next fragment's onCreate() , onCreateView() and onResume() is getting called. So, add onPageChangeListener on your viewPager like:

yourViewPager.addOnPageChangeListener(new OnPageChangeListener{
    @Override
        public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {}
        @Override
        public void onPageSelected(int position) {
        switch(position){
            //your code for network operation
        }
    }
    @Override
        public void onPageScrollStateChanged(int state) {}

});     

Answer 3

As others have mentioned, this is done for smooth loading of data in a view pager. What you can do though is call your code in onAattach() or when your fragment is visible to the user in onStart() . Android docs gives more details on lifecycle methods.