Android 使用viewPager在FragmentActivity内更改方向

我正在尝试构建一个应用程序，以纵向和横向模式显示一本书。所以很明显，有1页显示在肖像中，2页显示在风景中。每个模式都很好，但当我将方向从纵向更改为横向时，viewPager会尝试从纵向模式获取2页，而不是尝试从横向模式获取2页。。。 事实上，FragmentStatePagerAdapter保留了在纵向模式中创建的2个片段，并在为横向模式创建2个双页之前使用它们。如果我在纵向模式下再次切换，FragmentStatePagerAdapter将使用先前在横向模式下创建的2个片段，因此我再次看到1个双页而不是1个单页等。。如果我继续切换方向，我会得到一个OutOfMemory错误，因为FragmentStatePagerAdapter从未在方向更改时刷新它的片段

以下是两个更容易理解的用例：

• 我在纵向模式下启动viewPager
• 我看到第一页了，好吗
• 我向右滑动，看到第2页ok
• 我向右滑动，看到第3页ok
• 我将屏幕旋转到横向模式
• 我看第三页错了
• 我向右滑动，看到第4页错了
• 我向右滑动，看到第5页和第6页，好吗

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;
}

• 我在纵向模式下启动viewPager

• 我看到第一页了，好吗
• 我向右滑动，看到第2页ok
• 我向右滑动，看到第3页ok
• 我向右滑动，看到第4页ok
• 我向右滑动，看到第5页ok
• 我将屏幕旋转到横向模式
• 我看第5页错了
• 我向左滑动，看到第4页错了
• 我向左滑动，看到第2页和第3页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;
  }
  

  }

我已经读到框架中的FragmentManager负责保存状态并恢复寻呼机生成的任何活动片段。所以我猜当方向改变时，碎片管理者说

嘿！我已经创建了2个项目，所以我不需要创建新闻， 我们去拿吧

但事实上，它从旧的定向模式中获得了两个项目（页面/双页面）。因此，我需要找到一种方法，在方向发生变化时删除FragmentManager保存的片段

我也做了测试。这个问题似乎与

---

致以最诚挚的问候

尝试将方向限制为纵向或横向模式。因为我们只能在精确模式下使用“查看寻呼机”。

您如何解决此问题？