FragmentPagerAdapter getItem이 호출되지 않았습니다

FragmentPagerAdapter getItem이 호출되지 않았습니다

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FragmentPagerAdapter에서 프래그먼트를 재사용 할 수 없습니다. destroyItem () 메소드를 사용하여 프래그먼트를 삭제하고 있지만 여전히 getItem ()을 호출하지 않습니다. 2-3 이미지 만 있으므로 FragmentStatePagerAdapter 대신 FragmentPagerAdapter를 사용하고 있습니다.

public class ExamplePagerAdapter extends FragmentPagerAdapter {

    ArrayList < String > urls;
    int size = 0;
    public ExamplePagerAdapter(FragmentManager fm, ArrayList < String > res) {
        super(fm);
        urls = res;
        size = urls.size();
    }

    @Override
    public int getCount() {
        if (urls == null) {
            return 0;
        } else {
            return size;
        }

    }

    @Override
    public void destroyItem(ViewGroup container, int position, Object object) {
        FragmentManager manager = ((Fragment) object).getFragmentManager();
        FragmentTransaction trans = manager.beginTransaction();
        trans.remove((Fragment) object);
        trans.commit();
    }

    @Override
    public Fragment getItem(int position) {

        Fragment fragment = new FloorPlanFragment();
        Bundle b = new Bundle();
        b.putInt("p", position);
        b.putString("image", urls.get(position));
        Log.i("image", "" + urls.get(position));
        fragment.setArguments(b);
        return fragment;
    }
}

그리고 FragmentActivity에서

pager.setAdapter(new ExamplePagerAdapter(getSupportFragmentManager(), res2)); 

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키스 답변 :

간단한 사용 FragmentStatePagerAdapter 대신 FragmentPagerAdapter .

나는 첫째로 나는 매우 어리석은 실수를하고있는 중이 야 나는이 질문을 삭제 생각하지만이 대답은 그 대신 같은 문제에 직면하고 누군가 도움이 될 것입니다 .. 답을 가지고 FragmentPagerAdapter사용을 FragmentStatePagerAdapter.

의견에 @BlackHatSamurai가 언급했듯이 :

이것이 작동하는 이유 FragmentStatePagerAdapter는 사용되지 않는 조각으로 파괴 되기 때문 입니다. FragmentPagerAdapter하지 않습니다.

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를 사용하여 FragmentStatePagerAdapter내 문제를 완전히 해결하지 못했습니다 onCreateView. 뷰 호출기에서 하위 조각을 호출하지 않은 비슷한 문제 였습니다. 나는 실제로 내 FragmentPagerAdapter안에 다른Fragment 것을 내포하고 있기 때문에 FragmentManager모든 것들에 걸쳐 공유되어 오래된 조각의 인스턴스를 유지합니다. 수정은 대신 호스트 인스턴스의 getChildFragmentManager생성자에게 인스턴스를 공급하는 것이 었습니다 FragmentPagerAdapter. 뭔가 ...

FragmentPagerAdapter adapter = new FragmentPagerAdapter(getChildFragmentManager());

이 getChildFragmentManager()방법은 조각을 통해 액세스 할 수 FragmentManager있으며 중첩 조각이 필요한 상황에서 해당 조각에 대한 개인 정보 를 반환하기 때문에 저에게 효과적이었습니다. 나는 이것이 내가했던 것과 같은 문제를 겪고있는 누군가를 돕기를 바랍니다.

• Keep in mind however to use getChildFragmentManager() your minimum API version must be atleast 17 (4.2), so this may throw a wrench in your gears. Of course, if you are using fragments from the support library v4 you should be okay.

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I did what @kanika and @Jraco11 had posted but I still had the problem.

So, after a lot of changes, I found one that worked for me and was added to my FragmentPagerAdapter the next code:

    @Override
    public int getItemPosition(Object object) {
        return POSITION_NONE;
    }

According to what I read, getItemPosition is used to notify the ViewPager whether or not to refresh an item, and to avoid updates if the items at the visible positions haven't changed.

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There are two different scenarios : 1.) You have same layout for every pager : In that case, it will be better if you'll extend your custom adapter by PagerAdapter and return a single layout.

2.) You have different layout for every pager : In that case, it will be better if you'll extend your custom adapter by FragmentStatePagerAdapter and return different fragmets for every pager.

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Override long getItemId (int position)

FragmentPagerAdapter caches the fragments it creates using getItem. I was facing the same issue- even after calling notifyDataSetChanged() getItem was not being called.

This is actually a feature and not a bug. You need to override getItemId so that you can correctly reuse your fragments. Since you are removing fragments, your positions are changing. As mentioned in the docs:

long getItemId (int position)

Return a unique identifier for the item at the given position.

The default implementation returns the given position. Subclasses should override this method if the positions of items can change.

Just provide a unique id to each fragment and you're done.

Using a FragementStatePagerAdapter or returning POSITION_NONE in int getItemPosition (Object object) is wrong. You will not get any caching.

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method getItem() is used only to create new items. Once they created, this method will not be called. If you need to get item that is currency in use by adapter, use this method:

pagerAdapter.instantiateItem(viewPager, TAB_POS)

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I found that setting a listener on the tab-layout stopped this from being called, probably because they only have space for one listener on tabLayout.setOnTabSelectedListener instead of an array of listeners.

참고URL : https://stackoverflow.com/questions/12581896/fragmentpageradapter-getitem-is-not-called