I have a viewpager and a pagerAdapter which inflates a custom view and adds it to the collection. After setting up the viewpager and pageradapter, I proceed to get some data which I now want to display in one of the custom views. However I observed that the pagerAdapter.instantiateItem is not being called by that time. How can I get the viewpager to start instantiateItem right away?
instantiateItem is called when the viewPager calls the getItem method. When the viewPager is first displayed, getItem is called for the currently displayed tab and the following tab.
Could you provide a code snippet for further details ?
Related
I have 4 fragments attached with a viewpager. The 1st fragment has a spinner that has an item selected listener in onCreateView() method. Each time an item is picked from the spinner, a list adds that data.
Now when I swipe right to get to the other fragments, the 1st fragment is paused. Then if I come back to the 1st fragment the onCreateView() method runs again and loads the item selected listener again and adds the previosly added data again.
To avoid the situation I've taken the item selected listener inside an on touch listener. Now It's working as expected. But it just does not feel right. Any advice or help will be appreciated.
Thanks in advance.
Use this like this:
viewPager = (ViewPager) findViewById(R.id.viewpager);
viewPager.setOffscreenPageLimit(4); // 4 used for number of fragments like you are using 4 fragments using viewpager.
This setOffscreenPageLimit will not refresh your fragment again and again.
I'm displaying an Activity containing a ViewPager. In one of the Pager Fragment I have a ListView with a ContextMenu.
Long pressing on a List item displays the ContextMenu (onCreateContextMenu() is called), but selecting an entry in the ContextMenu doesn't call onContextItemSelected()
Using the same fragment outside the ViewPager works fine.
Is there something special to do in case the Fragment is embedded in a ViewPager ?
I hacked some code together and had a similar problem. I registered the ListView in Fragment 2 for context menu and unregistered Fragment 1. Yet somehow onContextItemSelected() was being called on Fragment 1.
Turns out that when the FragmentManager dispatches a ContextItemSelected event, it calls onContextItemSelected() on every single Fragment it knows about until one of them returns true. So in your onContextItemSelected(), you have to check if the fragment is the current page in the ViewPager; if it isn't, return false. This can be one source of problems.
See this SO question: Wrong fragment in ViewPager receives onContextItemSelected call
Hope that's helpful
I implemented View Pager with fragment child A/B/C. To get selection of default Fragment(say A) I use mViewPager.setCurrentItem(position) and it work fine. But on this Second Fragment (B) view methods onViewCreated and setUserVisibleHint calling automatically.
Is there any way to prevent this !
You can try invoking ViewPager.setOffscreenPageLimit(0), which will no longer pre-load non-visible Fragments. The default value for the off-screen page limit is 1, so that should be the reason why the onViewCreated() and setUserVisibleHint() methods are being called for your other fragments.
I have a view pager inside a fragment. Inside the inner fragment i have to show animation when the fragment is visible. i checked this answer and tried setUserVisibleHint and OnPageChangeListener both this are called before onCreateView and gives null pointer exception. how can i find when Fragment becomes visible in ViewPager so that i can start animation.
#bill gates, viewpager is the thing, in that both page (Current page and next or previous page) both are prepare simultaneously itself, so when you slide the current page two pages are visible to user. that a awesome function of viewpager. thanks.
I have ViewPager and FragmentStatePagerAdapter. I want to change dynamically content of ViewPager. For add page I use simple increase counter on 1 then call FragmentStatePagerAdapter.notifyDataSetChanged(). But if I want removing page:
destroyItem(viewPager, position, myAdapter.getItem(position));
getting error:
java.lang.IllegalStateException: Fragment MyPanel{40e80930} is not
currently in the FragmentManager
There is no destroyItem() method on ViewPager.
There is a destroyItem() method on PagerAdapter, but that is to be called by ViewPager, not by you.