TabLayoutインジケータがタブ間でハングアップし、コンテンツが消えます

Question

アプリのactivityにNavigationViewがあり、ナビゲーションドロワーUIのさまざまな項目がfragmentを変更して変更されました。そのようなフラグメントの1つにTabLayoutが実装されています。 TabLayoutでfragmentが起動しても問題なく機能しますが、navigation drawerのアイテムを切り替えてTabLayoutのアイテムに戻ったときにタブをスワイプすると、タブと1つのタブのコンテンツは表示されません。私は私がしたかもしれないミスについて何の手がかりも持っていません。私は、これはこれはapp_bar_start.xml

<?xml version="1.0" encoding="utf-8"?> 
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:app="http://schemas.android.com/apk/res-auto" 
    xmlns:tools="http://schemas.android.com/tools" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:fitsSystemWindows="true" 
    tools:context="com.optimilia.readaloud.Start"> 

    <android.support.design.widget.AppBarLayout 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content" 
     android:theme="@style/AppTheme.AppBarOverlay" 
     app:elevation="0dp"> 

     <android.support.v7.widget.Toolbar 
      android:id="@+id/toolbar" 
      android:layout_width="match_parent" 
      android:layout_height="?attr/actionBarSize" 
      android:background="?attr/colorPrimary" 
      app:popupTheme="@style/AppTheme.PopupOverlay"/> 

    </android.support.design.widget.AppBarLayout> 

    <FrameLayout 
     android:id="@+id/frame" 
     android:layout_width="match_parent" 
     android:layout_height="match_parent" 
     app:layout_behavior="@string/appbar_scrolling_view_behavior"/> 

</android.support.design.widget.CoordinatorLayout> 

これがあるのコードですNavigationView（activity_start.xml）

<?xml version="1.0" encoding="utf-8"?> 
<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:tools="http://schemas.android.com/tools" 
    xmlns:app="http://schemas.android.com/apk/res-auto" 
    android:id="@+id/drawer_layout" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:fitsSystemWindows="true" 
    tools:openDrawer="start"> 

    <include 
     layout="@layout/app_bar_start" 
     android:layout_width="match_parent" 
     android:layout_height="match_parent"/> 

    <android.support.design.widget.NavigationView 
     android:id="@+id/nav_view" 
     android:layout_width="wrap_content" 
     android:layout_height="match_parent" 
     android:layout_gravity="start" 
     android:fitsSystemWindows="true" 
     app:headerLayout="@layout/nav_header_start" 
     app:menu="@menu/start_menu" /> 

</android.support.v4.widget.DrawerLayout> 

を持っている活動です

compile 'com.android.support:appcompat-v7:24.2.1' 
compile 'com.android.support:design:24.2.1' 
compile 'com.android.support:support-v4:24.2.1' 

を使用していますTabLayoutを持つフラグメント（fragment_home.xml）

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:tools="http://schemas.android.com/tools" 
    xmlns:app="http://schemas.android.com/apk/res-auto" 
    android:id="@+id/activity_home" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:orientation="vertical" 
    tools:context="com.optimilia.readaloud.HomeFragment"> 

    <android.support.design.widget.AppBarLayout 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content" 
     android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"> 

     <android.support.design.widget.TabLayout 
      android:id="@+id/tabs" 
      android:layout_width="match_parent" 
      android:layout_height="@dimen/custom_tab_layout_height" 
      app:tabMode="fixed" 
      app:tabGravity="fill"/> 

    </android.support.design.widget.AppBarLayout> 

    <android.support.v4.view.ViewPager 
     android:id="@+id/viewpager" 
     android:layout_width="match_parent" 
     android:layout_height="match_parent" 
     app:layout_behavior="@string/appbar_scrolling_view_behavior" /> 

</LinearLayout> 

Start.java

public class Start extends AppCompatActivity { 

    private NavigationView navigationView; 
    private DrawerLayout drawer; 
    private Toolbar toolbar; 
    private Fragment homeFragment = null; 

    // index to identify current nav menu item 
    public static int navItemIndex = 0; 

    // tags used to attach the fragments 
    private static final String TAG_HOME = "Home"; 
    private static final String TAG_STORE = "Store"; 
    private static final String TAG_ABOUT = "About"; 
    private static final String TAG_SETTINGS = "Settings"; 
    private static final String TAG_HELP = "Help"; 

    public static String CURRENT_TAG = TAG_HOME; 

    // toolbar titles respected to selected nav menu item 
    private String[] activityTitles; 

    private Handler mHandler; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_start); 

     toolbar = (Toolbar) findViewById(R.id.toolbar); 
     setSupportActionBar(toolbar); 

     mHandler = new Handler(this.getMainLooper()); 

     drawer = (DrawerLayout) findViewById(R.id.drawer_layout); 
     navigationView = (NavigationView) findViewById(R.id.nav_view); 

     ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close); 
     drawer.addDrawerListener(toggle); 
     toggle.syncState(); 

     // load toolbar titles from string resources 
     activityTitles = getResources().getStringArray(R.array.nav_item_activity_titles); 

     // initializing navigation menu 
     setUpNavigationView(); 

     if (savedInstanceState == null) { 
      navItemIndex = 0; 
      CURRENT_TAG = TAG_HOME; 
      loadFragment(true); 
     } 
    } 

    private void loadFragment(boolean selectNavMenu) { 

     if (selectNavMenu) { 
      selectNavMenu(); 
     } 

     // set toolbar title 
     setToolbarTitle(); 

     // if user select the current navigation menu again, don't do anything 
     // just close the navigation drawer 
     if (getSupportFragmentManager().findFragmentByTag(CURRENT_TAG) != null) { 
      drawer.closeDrawers(); 
      return; 
     } 

     // Sometimes, when fragment has huge data, screen seems hanging 
     // when switching between navigation menus 
     // So using runnable, the fragment is loaded with cross fade effect 
     Runnable mPendingRunnable = new Runnable() { 
      @Override 
      public void run() { 
       // update the main content by replacing fragments 
       Fragment fragment = getFragment(); 
       FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction(); 
       fragmentTransaction.setCustomAnimations(android.R.anim.fade_in, android.R.anim.fade_out); 
       fragmentTransaction.replace(R.id.frame, fragment, CURRENT_TAG); 
       fragmentTransaction.commit(); 
      } 
     }; 

     // If mPendingRunnable is not null, then add to the message queue 
     if (mPendingRunnable != null) { 
      mHandler.post(mPendingRunnable); 
     } 

     drawer.closeDrawers(); 
     invalidateOptionsMenu(); 
    } 

    private Fragment getFragment() { 
     switch (navItemIndex) { 
      case 0: 
       if (homeFragment == null) { 
        homeFragment = new HomeFragment(); 
       } 
       return homeFragment; 
      case 1: 
       SettingsFragment settingsFragment = new SettingsFragment(); 
       return settingsFragment; 
//   case 2: 
//    // movies fragment 
//    MoviesFragment moviesFragment = new MoviesFragment(); 
//    return moviesFragment; 
//   case 3: 
//    // notifications fragment 
//    NotificationsFragment notificationsFragment = new NotificationsFragment(); 
//    return notificationsFragment; 
// 
//   case 4: 
//    // settings fragment 
//    SettingsFragment settingsFragment = new SettingsFragment(); 
//    return settingsFragment; 
      default: 
       return new HomeFragment(); 
     } 
    } 

    private void setToolbarTitle() { 
     getSupportActionBar().setTitle(activityTitles[navItemIndex]); 
    } 

    private void selectNavMenu() { 
     try { 
      navigationView.getMenu().getItem(navItemIndex).setChecked(true); 
     } 
     catch (Exception ex){} 
    } 

    private void setUpNavigationView() { 
     navigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() { 

      // This method will trigger on item Click of navigation menu 
      @Override 
      public boolean onNavigationItemSelected(MenuItem menuItem) { 

       //Check to see which item was being clicked and perform appropriate action 
       switch (menuItem.getItemId()) { 
        //Replacing the main content with ContentFragment Which is our Inbox View; 
        case R.id.nav_home: 
         navItemIndex = 0; 
         CURRENT_TAG = TAG_HOME; 
         break; 
        case R.id.nav_settings: 
         navItemIndex = 1; 
         CURRENT_TAG = TAG_SETTINGS; 
         break; 
        case R.id.nav_store: 
         navItemIndex = 2; 
         CURRENT_TAG = TAG_STORE; 
         break; 
        case R.id.nav_help: 
         navItemIndex = 3; 
         CURRENT_TAG = TAG_HELP; 
         break; 
        case R.id.nav_about: 
         navItemIndex = 4; 
         CURRENT_TAG = TAG_ABOUT; 
         break; 
        default: 
         navItemIndex = 0; 
       } 

       //Checking if the item is in checked state or not, if not make it in checked state 
       if (menuItem.isChecked()) { 
        menuItem.setChecked(false); 
       } else { 
        menuItem.setChecked(true); 
       } 
       menuItem.setChecked(true); 
       loadFragment(false); 
       return true; 
      } 
     }); 
    } 

    @Override 
    public void onBackPressed() { 
     if (drawer.isDrawerOpen(GravityCompat.START)) { 
      drawer.closeDrawers(); 
      return; 
     } 
     super.onBackPressed(); 
    } 
} 

HomeFragment.java

public class HomeFragment extends Fragment { 

    private View currView; 
    private TabLayout tabLayout; 
    private ViewPager viewPager; 
    private int[] tabIcons = { 
      R.drawable.ic_start, 
      R.drawable.ic_recent, 
      R.drawable.ic_reading_list 
    }; 

    public HomeFragment() { 
     // Required empty public constructor 
    } 

    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
    } 

    @Override 
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { 
     currView = inflater.inflate(R.layout.fragment_home, container, false); 

     viewPager = (ViewPager) currView.findViewById(R.id.viewpager); 
     setupViewPager(viewPager); 

     tabLayout = (TabLayout) currView.findViewById(R.id.tabs); 
     tabLayout.setupWithViewPager(viewPager); 
     setupTabIcons(); 

     return currView; 
    } 

    private void setupViewPager(ViewPager viewPager) { 
     HomeFragment.ViewPagerAdapter adapter = new HomeFragment.ViewPagerAdapter(getFragmentManager()); 
     adapter.addFragment(new StartFragment(), "Start"); 
     adapter.addFragment(new RecentFragment(), "Recent"); 
     adapter.addFragment(new ReadingListFragment(), "Reading list"); 
     viewPager.setAdapter(adapter); 
    } 

    private void setupTabIcons() { 
     tabLayout.getTabAt(0).setIcon(tabIcons[0]); 
     tabLayout.getTabAt(1).setIcon(tabIcons[1]); 
     tabLayout.getTabAt(2).setIcon(tabIcons[2]); 
    } 

    class ViewPagerAdapter extends FragmentPagerAdapter { 
     private final List<Fragment> mFragmentList = new ArrayList<>(); 
     private final List<String> mFragmentTitleList = new ArrayList<>(); 

     public ViewPagerAdapter(FragmentManager manager) { 
      super(manager); 
     } 

     @Override 
     public Fragment getItem(int position) { 
      return mFragmentList.get(position); 
     } 

     @Override 
     public int getCount() { 
      return mFragmentList.size(); 
     } 

     public void addFragment(Fragment fragment, String title) { 
      mFragmentList.add(fragment); 
      mFragmentTitleList.add(title); 
     } 

     @Override 
     public CharSequence getPageTitle(int position) { 
      return mFragmentTitleList.get(position); 
     } 
    } 

} 

私は2日間、このバグで立ち往生していますし、役に立つ何かを見つけることができませんでした。どんな種類の助けでも高く評価されます。

Answer 1

HomeFragment.javaはgetFragmentManager()をViewPagerAdapterに使用していましたが、これは問題を引き起こしていました。 getChildFragmentManager()に切り替えると、完全に動作し始めました。