CODEWITHSUNDEEP
androidandroid-fragmentsandroid-viewpagerandroid-recyclerview
usernotnull
usernotnull

Reputation: 3628

ViewPager fragments handling a change

When viewpager displays one fragment, it will automatically load the fragment pages around it for performance reasons. In my fragments, i have recycleviews with a popup menu to delete one item in the list.

I am facing a problem of deleting one item from one fragment, but that item still exists in the other preloaded fragments after I scroll to them. It works only if I force the viewpager to reload the contents of its fragments by manually scrolling back and forth the fragments.

Is there a way to force reload the preloaded fragments by viewpager?

Upvotes: 1

Views: 289

Answers (5)

usernotnull
usernotnull

Reputation: 3628

The answers helped me find the solution.

For future reference, I used a callback every time I used deleteItem(), and took a list of the loaded frags by using the method [FragmentHostingViewPager].getChildFragmentManager().getFragments()

Then I iterated through each fragment as long as each fragment was not null, and called a refresh() method on them.

Upvotes: 0

savepopulation
savepopulation

Reputation: 11921

First create an interface to detect changes in your RecyclerView:

public interface MyRecyclerViewChangeListener(){
   void onRecyclerViewDataChanged(int id);
}

Create a static variable in your Fragment or Activity which contains your viewpager:

public static List<MyRecyclerViewChangeListener> mListeners = new ArrayList();

Implement your interface to your ViewPagerFragments and do what you want in method you implemented.

In your fragment's onResume register your listener to mListeners like blow to detect changes:

MyFragmentOrActivity.mListeners.add(this);

And in your fragment's onPause unregister your listener:

MyFragmentOrActivity.mListeners.remove(this);

Finally notify your listeners when your recyclerview data changed:

for(MyRecyclerViewChangeListener listener : mListeners){
    listener.onRecyclerViewDataChanged(id);
}

Edit : If you are changing your recyclerview's data after an async task result such as a web api call, you can register your listener in fragment's onCreateView method and un register in onDestroyView method. So you can catch changes in your fragments.

Upvotes: 1

dex
dex

Reputation: 5240

Try setting mViewPager.setOffscreenPageLimit(1) such that it will not pre-cache any fragment or you could use FragmentStatePagerAdapter inside viewPager to achieve what you want.

Edit 1: So Conclusion is : 1) Use local broadcast mechanism to update the fragments present in ViewPager adapter

2) Use handler mechanism to refresh these fragments

3) if you want to blindly update these fragments once they are visible to users then do it inside onPageChangeListener of view pager method.

Upvotes: 0

Jithin Sunny
Jithin Sunny

Reputation: 3402

Your problem can be solved by using Interface. Google suggest using callbacks\listeners that are managed by your main Activity for communicating between fragments.You can use Interface which tells the other fragment to refresh its listview when you delete an item in current fragment.

For an overview http://developer.android.com/training/basics/fragments/communicating.html

Also a good question about this How to pass data between fragments

Upvotes: 1

Dolan
Dolan

Reputation: 103

I am not sure if i'm getting your question right but i think this should do it.

YourViewpager.setOffscreenPageLimit(0);

Now the fragment should be destroyed if it is not active and will be recreated if you open it again.So the data change should be recognized.

Hope I could help

Upvotes: 0

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