ViewPager - fragment seems to be not visible

[Máté Rémiás]

Hi,

I have a ViewPager, and 3 fragments inside. the ViewPager's onPageChangeListener calls each fragment's onResume to refresh its content when they get visible. in onResume I check if fragment isVisible() to only call refresh if fragment was added to the activity, and it works if I newly start the app, but sometimes when I come back to the app after it was sent to background, than the onresume returns false to isVisible() (and fragment content is not shown), which is really strange, since the fragment's menu is populated and if I call the refresh from the fragment's menu than it is loading and refreshing the UI content. So my question is if this behaviour is normal and I implemented something wrong, or this is a bug?

could you please help?

thanks in advance

rm

[Máté Rémiás]

let me be more specific:

I have 3 fragments in a viewpager, the first one is shown when the app loads.

the 2nd and 3rd pages are a bit CPU intensive, so I would like to load their content only when user swipes to them first.

for this I have implemented ViewPager.OnPageChangeListener

and overrode onPageSelected to call an onResume in the Fragment

public void onPageSelected(int position) {

getItem(viewPager.getCurrentItem()).onResume();

}

in the Fragments onResume is the following:

@Override

public void onResume() {

super.onResume();

if ((MainActivity) getActivity() != null && ((MainActivity) getActivity()).pager != null && ((MainActivity) getActivity()).pager.getCurrentItem() == 1) {

doCpuIntensiveLoading();

}

}

to prevent it from loading when instantiated and not visible, but to load when pager's getCurrentItem() returns the fragment's id.

but! when I scroll to the page getActivity() returns null although the fragment's menu is populated and calling load from menu is working.

please let me know if you need more details.

[Jake Wharton]

This kind of question is really better suited for the official Android developer mailing list or StackOverflow. Even though ViewPager is bundled with ActionBarSherlock its part of the compatibility library and not specifically this library. You will reach a much wider audience with either one of the two linked resources as the people on this mailing list are usually only concerned with the action bar functionality that has been added.

---
Jake Wharton
http://about.me/jakewharton

[Máté Rémiás]

thanks http://stackoverflow.com/q/8596231/310078 this is the posted issue if anyone wants to follow