I'm trying to build an app that shows a book in portrait and landscape mode. So obviously there's 1 page showed in portrait and 2 in landscape. Each of the mode works pretty good but when i change the orientation from portrait to landscape the viewPager try to get 2 pages from the portrait mode instead of trying to get 2 double pages from the landscape mode ... In fact FragmentStatePagerAdapter keeps The 2 fragments created in portrait and uses them before creating 2 double page for the landscape mode. If i switch again in portrait mode, FragmentStatePagerAdapter uses the 2 fragments previously created in landscape mode so i see again 1 double page instead of 1 single page etc.. if i continue switching orientation, i get an OutOfMemoryError due to the fact that FragmentStatePagerAdapter never flush it's fragments on orientation change.
Here's 2 use cases for easier understanding :
- i launch viewPager in portrait mode
- i see page 1 ok
- i swipe to right and i see page 2 ok
- i swipe to right and i see page 3 ok
- i rotate the screen to landscape mode
- i see page 3 wrong
- i swipe to right and i see page 4 wrong
i swipe to right and i see page 5 and 6 ok
i launch viewPager in portrait mode
- i see page 1 ok
- i swipe to right and i see page 2 ok
- i swipe to right and i see page 3 ok
- i swipe to right and i see page 4 ok
- i swipe to right and i see page 5 ok
- i rotate the screen to landscape mode
- i see page 5 wrong
- i swipe to left and i see page 4 wrong
i swipe to left and i see page 2 and 3 ok
public class PlayerFragmentActivity extends FragmentActivity { private Intent mIntent; private ViewPager mPortraitPager; private ViewPager mLandscapePager; private Boolean mIsLandscape; private String mKey; private int mNbPages; private int mNbDoublePages; private PageFactory mPageFactory; private DoublePageFactory mDoublePageFactory; private PagerAdapter mPagerAdapter; @Override protected void onStop(){ super.onStop(); mPagerAdapter = null; mDoublePageFactory = null; mPageFactory = null; } @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.fragment_activity_player); mIntent = getIntent(); mKey = mIntent.getStringExtra("key"); mNbPages = mIntent.getIntExtra("nbPages", 0); mNbDoublePages = DoublePageFactory.getDoublePageNumFromPageNum(mNbPages); Resources res = getResources(); mIsLandscape = (res.getConfiguration().orientation == 1) ? false : true; mPortraitPager = (ViewPager) findViewById(R.id.portraitPager); mLandscapePager = (ViewPager) findViewById(R.id.landscapePager); mPagerAdapter = new MyPagerAdapter(getSupportFragmentManager()); if (mIsLandscape) { mDoublePageFactory = new DoublePageFactory(this, mKey, mNbPages, res.getInteger(R.integer.nb_page_columns), res.getInteger(R.integer.nb_page_columns)); mPortraitPager.setVisibility(View.GONE); mLandscapePager.setAdapter(mPagerAdapter); mPortraitPager.setAdapter(null); } else { mPageFactory = new PageFactory(this, mKey, this.mNbPages, res.getInteger(R.integer.nb_page_columns), res.getInteger(R.integer.nb_page_columns)); mLandscapePager.setVisibility(View.GONE); mPortraitPager.setAdapter(mPagerAdapter); mLandscapePager.setAdapter(null); } } public class MyPagerAdapter extends FragmentStatePagerAdapter { public MyPagerAdapter(FragmentManager fm) { super(fm); } @Override public Fragment getItem(int position) { Bundle args = new Bundle(); if(mIsLandscape){ Fragment doublePageFragment = new DoublePageFragment(); args.putInt(DoublePageFragment.ARG_DOUBLEPAGE_NUM, position + 1); doublePageFragment.setArguments(args); return doublePageFragment; }else{ Fragment pageFragment = new PageFragment(); args.putInt(PageFragment.ARG_PAGE_NUM, position + 1); pageFragment.setArguments(args); return pageFragment; } } @Override public int getCount() { return (mIsLandscape) ? mNbDoublePages:mNbPages; } /* j'ai essayé cette méthode mais ça ne fonctionne pas :( */ @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(); super.destroyItem(container, position, object); } @Override public int getItemPosition(Object object){ return PagerAdapter.POSITION_NONE; } @Override public CharSequence getPageTitle(int position) { return "p." + position + 1; } } public boolean isLandscape() { return mIsLandscape; } public ImageView getSinglePage(int position) { return mPageFactory.getPage(position); } public LinearLayout getDoublePage(int position) { return mDoublePageFactory.getDoublePage(position); } } public class PageFragment extends Fragment { private PlayerFragmentActivity mPlayerFragmentActivity; public static final String ARG_PAGE_NUM = "page_number"; public static final String ARG_WOBOOK_DIRECTORY = "book_directory"; public static final String ARG_NB_PAGE_COLUMNS = "nb_page_columns"; public static final String ARG_NB_PAGE_ROWS = "nb_page_rows"; @Override public ImageView onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { mPlayerFragmentActivity = ((PlayerFragmentActivity) getActivity()); return mPlayerFragmentActivity.getSinglePage(getArguments().getInt(ARG_PAGE_NUM)); } @Override public void onStop(){ super.onStop(); mPlayerFragmentActivity = null; }}
public class DoublePageFragment extends Fragment { private PlayerFragmentActivity mPlayerFragmentActivity; public static final String ARG_DOUBLEPAGE_NUM = "double_page_number"; public static final String ARG_WOBOOK_DIRECTORY = "book_directory"; public static final String ARG_NB_PAGE_COLUMNS = "nb_page_columns"; public static final String ARG_NB_PAGE_ROWS = "nb_page_rows"; @Override public LinearLayout onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { mPlayerFragmentActivity = ((PlayerFragmentActivity) getActivity()); return mPlayerFragmentActivity.getDoublePage(getArguments().getInt(ARG_DOUBLEPAGE_NUM)); } @Override public void onStop(){ super.onStop(); mPlayerFragmentActivity = null; } }
i've read that the FragmentManager in the framework takes care of saving the state and restore any active fragments that the pager has made. So i guess that when the orientation changes, the FragmentManager says
Hey ! I already have 2 items created so i don't need to create news, lets get them
But in fact it gets the 2 items (page/double page) from the old orientation mode. So i need to fnd a way to delete the fragments saved by the FragmentManager when the orientation change occurs.
I've also tested this method. The problem seems to be related to this one
Best regards
