導航抽屜+ ViewPager +片段，ViewPager不會銷燬嵌套片段

Question

我的應用程序有導航抽屜有兩個項目：ViewPager（片段內）和SupportMapFragment。

ViewPager使用FragmentStatePagerAdapter和getItem(int position)返回兩個片段。

當我打開抽屜式導航欄和我選擇「項目1」（SupportMapFragment），另一個片段（ViewPager是這種內部）執行onDestroy() method但這種方法不破壞由適配器創建的，因此當所述片段我再次選擇「item 0」，我的應用程序創建ViewPager及其兩個項目以及ViewPager未刪除的其他兩個碎片。

這個問題創造薩姆斯片段時，我選擇「項目1」，然後「項目0」 ......於是片段數量的增加。

ViewPager在其容器片段執行onDestroy時如何移除這些片段？

我的代碼

MainActivity

public class Main extends SherlockFragmentActivity { 

//Nombre de los elementos de la lista 
private String[] mTitles; 
private DrawerLayout mDrawerLayout; 
private ActionBarDrawerToggle mDrawerToggle; 
private ListView mDrawerList; 

private int currentPosition; 

@Override 
public void onCreate(Bundle savedInstanceState){ 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.main_navigation_drawer); 

    //Inicialmente no hay ninguna opcion 
    currentPosition = -1; 

    mDrawerLayout = (DrawerLayout)findViewById(R.id.drawer_layout); 
    mDrawerList = (ListView)findViewById(R.id.left_drawer); 
    mDrawerToggle = new ActionBarDrawerToggle(
      this, 
      mDrawerLayout, 
      R.drawable.ic_drawer, 
      R.string.drawer_open, 
      R.string.drawer_close) { 

     /** Called when a drawer has settled in a completely closed state. */ 
     public void onDrawerClosed(View view) { 
      // creates call to onPrepareOptionsMenu() 
      supportInvalidateOptionsMenu(); 
     } 

     /** Called when a drawer has settled in a completely open state. */ 
     public void onDrawerOpened(View drawerView) {    
      // creates call to onPrepareOptionsMenu() 
      supportInvalidateOptionsMenu(); 
     } 
    }; 

    mTitles = getResources().getStringArray(R.array.navigation_drawer_options); 

    //Asignamos el Adapter 
    mDrawerList.setAdapter(new ArrayAdapter<String>(this,R.layout.drawer_list_item, mTitles)); 
    //Asignamos el listener 
    mDrawerList.setOnItemClickListener(new DrawerItemClickListener()); 

    mDrawerLayout.setDrawerListener(mDrawerToggle); 
    getSupportActionBar().setDisplayHomeAsUpEnabled(true); 
    getSupportActionBar().setHomeButtonEnabled(true); 

    if (savedInstanceState == null) { 
     selectItem(0); 
    } 
} 

@Override 
protected void onPostCreate(Bundle savedInstanceState) { 
    super.onPostCreate(savedInstanceState); 
    // Sync the toggle state after onRestoreInstanceState has occurred. 
    mDrawerToggle.syncState(); 
} 

@Override 
public void onConfigurationChanged(Configuration newConfig) { 
    super.onConfigurationChanged(newConfig); 
    mDrawerToggle.onConfigurationChanged(newConfig); 
} 

private class DrawerItemClickListener implements ListView.OnItemClickListener { 

    @Override 
    public void onItemClick(AdapterView<?> parent, View view, int position, long id) { 
     selectItem(position); 
    } 
} 

/** Swaps fragments in the main content view */ 
private void selectItem(int position) { 
    // Create a new fragment and specify the planet to show based on position 

    if(currentPosition != position){ 
     //Solo hacemos remplazo de fragment si la opcion selecionada no es la misma 
     //que la que esta ya en pantalla 
     Fragment fragment = null; 
     String fragmentName = ""; 
     boolean attach = true; 

     switch (position) { 
      case 0: 
       fragmentName = PagerFragment.class.getSimpleName(); 
       fragment = getSupportFragmentManager().findFragmentByTag(fragmentName); 
       if(fragment == null) { 
        fragment = new PagerFragment(); 
        attach = false; 
       } 
       break; 
      case 1: 
       fragmentName = Map1Fragment.class.getSimpleName(); 
       fragment = getSupportFragmentManager().findFragmentByTag(fragmentName); 
       if(fragment == null) { 
        fragment = new Map1Fragment(); 
        attach = false; 
       } 
       break;  
      default: 
       throw new IllegalArgumentException("Posicion no valida"); 
     } 

     // Insert the fragment by replacing any existing fragment 
     FragmentManager fragmentManager = getSupportFragmentManager(); 
     FragmentTransaction transaction = fragmentManager.beginTransaction(); 
     if(!attach){ 
      transaction.replace(R.id.content_frame, fragment); 
     }else{ 
      transaction.attach(fragment); 
     } 
     transaction.commit(); 
    } 
    currentPosition = position; 
    // Highlight the selected item, update the title, and close the drawer 
    mDrawerList.setItemChecked(position, true);  
    mDrawerLayout.closeDrawer(mDrawerList); 
} 

}

片段與ViewPager

public class PagerFragment extends SherlockFragment{ 

private ViewPager viewPager; 

@Override 
public View onCreateView(LayoutInflater inflater, ViewGroup container, 
       Bundle savedInstanceState) { 
    Log.d("PagerFragment", "onCreateView"); 
    return inflater.inflate(R.layout.application_tus, container, false); 
} 

@Override 
public void onViewCreated(View view, Bundle savedInstanceState) { 
     super.onViewCreated(view, savedInstanceState); 
     Log.d("PagerFragment", "onViewCreated"); 
     viewPager = (ViewPager) view.findViewById(R.id.viewpager); 
     viewPager.setAdapter(new ViewPagerAdapter(getSherlockActivity(), getFragmentManager())); 

     TitlePageIndicator titleIndicator = (TitlePageIndicator)view.findViewById(R.id.titles_viewpager); 
     titleIndicator.setViewPager(viewPager,0); 

} 
} 

FragmentStatePagerAdapter

public class ViewPagerAdapter extends FragmentStatePagerAdapter{ 

public static final int NUM_PAGES = 2; 
public static final int [] titles = { R.string.st1, R.string.st2}; 

private Context context; 

public ViewPagerAdapter(Context context, FragmentManager fragmentManager) { 
    super(fragmentManager); 
    this.context = context; 
} 

@Override 
public Fragment getItem(int position) { 
    Log.d("ViewPagerAdapter", "GetItem(" + position+")"); 
    switch (position) { 
     case 0: 
      return new FavoritesFragment();   
     case 1: 
      return new LinesFragment();  
     default: 
      throw new IllegalArgumentException("Error"); 
    } 
} 

@Override 
public int getCount() { 
    return NUM_PAGES; 
} 

@Override 
public CharSequence getPageTitle(int position) { 
    return context.getString(titles[position]); 
} 

} 

Answer 1

我終於解決了我的問題。

當我創建FragmentStatePagerAdapter時，我使用new ViewPagerAdapter(getSherlockActivity(), getFragmentManager())。我終於使用了getChildFragmentManager()，它的工作！