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TabLayout Android dans Fragment

J'utilise Navigation Drawer pour naviguer entre les fragments; ils utilisent tous la barre d'outils MainActivity mais chaque fragment a sa propre TabLayout avec 3 onglets et dans chaque onglet, j'utilise RecyclerView pour afficher différents textes et images.

Je l'ai fait la dernière fois en utilisant des actvités au lieu de fragments, mais maintenant, en utilisant le tiroir, il est préférable d'utiliser des fragments. 

Je suis arrivé au point où les onglets fonctionnent, mais dès que je mets la ViewPager et connecte les adaptateurs aux onglets et que j'ouvre le nouveau fragment du tiroir, j'obtiens un pointeur Null, quel est le problème ici? 

MainActivity.Java

public class MainActivity extends AppCompatActivity

    implements NavigationView.OnNavigationItemSelectedListener {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);

    DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
    ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
            this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
    drawer.setDrawerListener(toggle);
    toggle.syncState();

    NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
    navigationView.setNavigationItemSelectedListener(this);
}

@Override
public void onBackPressed() {
    DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
    if (drawer.isDrawerOpen(GravityCompat.START)) {
        drawer.closeDrawer(GravityCompat.START);
    } else {
        super.onBackPressed();
    }
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    int id = item.getItemId();
    return id == R.id.action_settings || super.onOptionsItemSelected(item);

}

@Override
public boolean onNavigationItemSelected(MenuItem item) {
    int id = item.getItemId();
    Fragment fragment;

    if (id == R.id.fragment_one) {
        fragment = new NewFragment();
        FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
        ft.replace(R.id.container, fragment);
        ft.commit();

    } else if (id == R.id.fragment_two) {

        fragment = new NewFragment();
        FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
        ft.replace(R.id.container, fragment);
        ft.commit();

    } else if (id == R.id.fragment_three) {

        fragment = new NewFragment();
        FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
        ft.replace(R.id.container, fragment);
        ft.commit();

    }

    DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
    drawer.closeDrawer(GravityCompat.START);
    return true;
}
}

activity_main.xml

<Android.support.v4.widget.DrawerLayout 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:id="@+id/drawer_layout"
Android:layout_width="match_parent"
Android:layout_height="match_parent"
Android:fitsSystemWindows="true"
tools:openDrawer="start">

<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.xcandy.guideforfifa17.MainActivity">

    <Android.support.design.widget.AppBarLayout
        Android:layout_width="match_parent"
        Android:layout_height="wrap_content"
        Android:theme="@style/AppTheme.AppBarOverlay">

        <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>

    <include layout="@layout/content_main" />

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

<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_main"
    app:menu="@menu/activity_main_drawer" />

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

NewFragment.Java

public class NewFragment extends Fragment {

private RecyclerView mRecyclerView;


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

    TabLayout tabLayout = (TabLayout) view.findViewById(R.id.tabs);
    tabLayout.addTab(tabLayout.newTab().setText("A"));
    tabLayout.addTab(tabLayout.newTab().setText("B"));
    tabLayout.addTab(tabLayout.newTab().setText("C"));

    final ViewPager viewPager = (ViewPager) view.findViewById(R.id.viewpager);

    mRecyclerView = (RecyclerView) view.findViewById(R.id.recycler_view);

    RecyclerView.LayoutManager mLayoutManager = new LinearLayoutManager(getActivity());
    mRecyclerView.setLayoutManager(mLayoutManager);


    viewPager.setAdapter(new PagerAdapter
            (getFragmentManager(), tabLayout.getTabCount()));
    viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
    tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {

        @Override
        public void onTabSelected(TabLayout.Tab tab) {
            viewPager.setCurrentItem(tab.getPosition());
        }

        @Override
        public void onTabUnselected(TabLayout.Tab tab) {

        }

        @Override
        public void onTabReselected(TabLayout.Tab tab) {

        }
    });

    return view;
}

public class PagerAdapter extends FragmentStatePagerAdapter {
    int mNumOfTabs;

    public PagerAdapter(FragmentManager fm, int NumOfTabs) {
        super(fm);
        this.mNumOfTabs = NumOfTabs;
    }



    @Override
    public Fragment getItem(int position) {

        switch (position) {
            case 0:

                RecyclerView.Adapter mAdapter = new AdapterOne();
                mRecyclerView.setAdapter(mAdapter);

            case 1:

                mAdapter = new AdapterTwo();
                mRecyclerView.setAdapter(mAdapter);

            case 2:

                mAdapter = new AdapterThree();
                mRecyclerView.setAdapter(mAdapter);

            default:
                return null;
        }
    }

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

activity_fragment.xml

<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=".NewFragment">

<Android.support.design.widget.AppBarLayout
    Android:layout_width="match_parent"
    Android:layout_height="wrap_content"
    Android:theme="@style/AppTheme.AppBarOverlay">

    <Android.support.design.widget.TabLayout
        Android:id="@+id/tabs"
        Android:layout_width="match_parent"
        Android:layout_height="wrap_content"
        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="wrap_content"
    Android:background="@Android:color/white"/>

<Android.support.v7.widget.RecyclerView
    Android:id="@+id/recycler_view"
    Android:layout_width="match_parent"
    Android:layout_height="match_parent"
    />

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

Journal des erreurs

                  --------- beginning of crash
06-23 11:19:56.985 2466-2466/com.candyx.sims E/AndroidRuntime: FATAL EXCEPTION: main
                                                               Process: com.candyx.sims, PID: 2466
                                                               Java.lang.NullPointerException: Attempt to invoke virtual method 'void Android.support.v7.widget.RecyclerView.setLayoutManager(Android.support.v7.widget.RecyclerView$LayoutManager)' on a null object reference
                                                                   at com.candyx.sims.BlankFragment.onCreateView(BlankFragment.Java:38)
                                                                   at Android.support.v4.app.Fragment.performCreateView(Fragment.Java:1974)
                                                                   at Android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.Java:1067)
                                                                   at Android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.Java:1252)
                                                                   at Android.support.v4.app.BackStackRecord.run(BackStackRecord.Java:742)
                                                                   at Android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.Java:1617)
                                                                   at Android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.Java:517)
                                                                   at Android.os.Handler.handleCallback(Handler.Java:739)
                                                                   at Android.os.Handler.dispatchMessage(Handler.Java:95)
                                                                   at Android.os.Looper.loop(Looper.Java:135)
                                                                   at Android.app.ActivityThread.main(ActivityThread.Java:5254)
                                                                   at Java.lang.reflect.Method.invoke(Native Method)
                                                                   at Java.lang.reflect.Method.invoke(Method.Java:372)
                                                                   at com.Android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.Java:903)
                                                                   at com.Android.internal.os.ZygoteInit.main(ZygoteInit.Java:698)
06-23 11:23:14.912 5839-5873/com.candyx.sims D/OpenGLRenderer: Use EGL_SWAP_BEHAVIOR_PRESERVED: true

                                                               [ 06-23 11:23:14.920  5839: 5839 D/         ]
                                                               HostConnection::get() New Host Connection established 0xb4125190, tid 5839
06-23 11:23:14.927 5839-5839/com.candyx.sims D/Atlas: Validating map...
06-23 11:23:15.011 5839-5873/com.candyx.sims I/OpenGLRenderer: Initialized EGL, version 1.4
06-23 11:23:15.027 5839-5873/com.candyx.sims D/OpenGLRenderer: Enabling debug mode 0
06-23 11:23:15.039 5839-5873/com.candyx.sims W/EGL_emulation: eglSurfaceAttrib not implemented
06-23 11:23:15.039 5839-5873/com.candyx.sims W/OpenGLRenderer: Failed to set EGL_SWAP_BEHAVIOR on surface 0xae838600, error=EGL_SUCCESS
06-23 11:23:16.444 5839-5839/com.candyx.sims W/PathParser: Points are too far apart 4.000000596046461
06-23 11:23:17.342 5839-5839/com.candyx.sims W/PathParser: Points are too far apart 4.000000596046461
06-23 11:23:17.350 5839-5839/com.candyx.sims I/AppCompatViewInflater: app:theme is now deprecated. Please move to using Android:theme instead.
06-23 11:23:17.369 5839-5839/com.candyx.sims D/AndroidRuntime: Shutting down VM
06-23 11:23:17.369 5839-5839/com.candyx.sims E/AndroidRuntime: FATAL EXCEPTION: main
                                                               Process: com.candyx.sims, PID: 5839
                                                               Java.lang.NullPointerException: Attempt to invoke virtual method 'void Android.support.v7.widget.RecyclerView.setLayoutManager(Android.support.v7.widget.RecyclerView$LayoutManager)' on a null object reference
                                                                   at com.candyx.sims.NewFragment.onCreateView(NewFragment.Java:38)
                                                                   at Android.support.v4.app.Fragment.performCreateView(Fragment.Java:1974)
                                                                   at Android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.Java:1067)
                                                                   at Android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.Java:1252)
                                                                   at Android.support.v4.app.BackStackRecord.run(BackStackRecord.Java:742)
                                                                   at Android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.Java:1617)
                                                                   at Android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.Java:517)
                                                                   at Android.os.Handler.handleCallback(Handler.Java:739)
                                                                   at Android.os.Handler.dispatchMessage(Handler.Java:95)
                                                                   at Android.os.Looper.loop(Looper.Java:135)
                                                                   at Android.app.ActivityThread.main(ActivityThread.Java:5254)
                                                                   at Java.lang.reflect.Method.invoke(Native Method)
                                                                   at Java.lang.reflect.Method.invoke(Method.Java:372)
                                                                   at com.Android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.Java:903)
                                                                   at com.Android.internal.os.ZygoteInit.main(ZygoteInit.Java:698)
06-23 11:25:16.961 7518-7518/com.candyx.sims W/art: Before Android 4.1, method Android.graphics.PorterDuffColorFilter Android.support.graphics.drawable.VectorDrawableCompat.updateTintFilter(Android.graphics.PorterDuffColorFilter, Android.content.res.ColorStateList, Android.graphics.PorterDuff$Mode) would have incorrectly overridden the package-private method in Android.graphics.drawable.Drawable
06-23 11:25:17.078 7518-7548/com.candyx.sims D/OpenGLRenderer: Use EGL_SWAP_BEHAVIOR_PRESERVED: true

                                                               [ 06-23 11:25:17.081  7518: 7518 D/         ]
                                                               HostConnection::get() New Host Connection established 0xb412a1f0, tid 7518
06-23 11:25:17.082 7518-7518/com.candyx.sims D/Atlas: Validating map...
06-23 11:25:17.109 7518-7548/com.candyx.sims I/OpenGLRenderer: Initialized EGL, version 1.4
06-23 11:25:17.126 7518-7548/com.candyx.sims D/OpenGLRenderer: Enabling debug mode 0
06-23 11:25:17.134 7518-7548/com.candyx.sims W/EGL_emulation: eglSurfaceAttrib not implemented
06-23 11:25:17.134 7518-7548/com.candyx.sims W/OpenGLRenderer: Failed to set EGL_SWAP_BEHAVIOR on surface 0xb41234c0, error=EGL_SUCCESS
06-23 11:25:31.030 7518-7518/com.candyx.sims W/PathParser: Points are too far apart 4.000000596046461
06-23 11:25:32.174 7518-7518/com.candyx.sims W/PathParser: Points are too far apart 4.000000596046461
06-23 11:25:32.187 7518-7518/com.candyx.sims I/AppCompatViewInflater: app:theme is now deprecated. Please move to using Android:theme instead.
06-23 11:25:32.207 7518-7518/com.candyx.sims D/AndroidRuntime: Shutting down VM
06-23 11:25:32.207 7518-7518/com.candyx.sims E/AndroidRuntime: FATAL EXCEPTION: main
                                                               Process: com.candyx.sims, PID: 7518
                                                               Java.lang.NullPointerException: Attempt to invoke virtual method 'void Android.support.v7.widget.RecyclerView.setLayoutManager(Android.support.v7.widget.RecyclerView$LayoutManager)' on a null object reference
                                                                   at com.candyx.sims.NewFragment.onCreateView(NewFragment.Java:38)
                                                                   at Android.support.v4.app.Fragment.performCreateView(Fragment.Java:1974)
                                                                   at Android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.Java:1067)
                                                                   at Android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.Java:1252)
                                                                   at Android.support.v4.app.BackStackRecord.run(BackStackRecord.Java:742)
                                                                   at Android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.Java:1617)
                                                                   at Android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.Java:517)
                                                                   at Android.os.Handler.handleCallback(Handler.Java:739)
                                                                   at Android.os.Handler.dispatchMessage(Handler.Java:95)
                                                                   at Android.os.Looper.loop(Looper.Java:135)
                                                                   at Android.app.ActivityThread.main(ActivityThread.Java:5254)
                                                                   at Java.lang.reflect.Method.invoke(Native Method)
                                                                   at Java.lang.reflect.Method.invoke(Method.Java:372)
                                                                   at com.Android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.Java:903)
                                                                   at com.Android.internal.os.ZygoteInit.main(ZygoteInit.Java:698)
androidandroid-fragmentsandroid-recyclerviewandroid-tablayout
15
Jacques Krause

Après avoir examiné votre code, j’ai trouvé que vous oubliez de renvoyer un fragment dans la méthode getItem de PagerAdapter que vous avez remplacé par FragmentStatePagerAdapter.

Pour ce faire, vous devez créer un nouveau fragment pour chaque page dans ViewPager ou vous pouvez créer un nouveau fragment pouvant être utilisé dans toutes les pages de ViewPager.

Vous ne pouvez pas utiliser la même vue de recyclage dans les onglets du pageur de vue que vous avez définis dans le fragment parent. 

activity_fragment_one.xml

 <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=".NewFragment">

    <Android.support.design.widget.AppBarLayout
        Android:layout_width="match_parent"
        Android:layout_height="wrap_content"
        Android:theme="@style/AppTheme.AppBarOverlay">

        <Android.support.design.widget.TabLayout
            Android:id="@+id/tabs"
            Android:layout_width="match_parent"
            app:layout_behavior="@string/appbar_scrolling_view_behavior"
            app:tabTextAppearance="?android:attr/textAppearanceMedium"
            app:tabTextColor="#ffffff"
            Android:layout_height="?android:actionBarSize"
            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="wrap_content"
        app:layout_behavior="@string/appbar_scrolling_view_behavior"
        Android:background="@Android:color/white"/>
</Android.support.design.widget.CoordinatorLayout>

J'ai corrigé votre fragment et créé un nouveau fragment que vous pouvez utiliser dans les pages ViewPager.

public class NewFragment extends Fragment {

private RecyclerView mRecyclerView;


@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.activity_fragment_one, container, false);
    TabLayout tabLayout = (TabLayout) view.findViewById(R.id.tabs);
    tabLayout.addTab(tabLayout.newTab().setText("A"));
    tabLayout.addTab(tabLayout.newTab().setText("B"));
    tabLayout.addTab(tabLayout.newTab().setText("C"));
    final ViewPager viewPager = (ViewPager) view.findViewById(R.id.viewpager);
   // mRecyclerView = (RecyclerView) view.findViewById(R.id.recycler_view);
    LinearLayoutManager mLayoutManager = new LinearLayoutManager(getActivity());
    mLayoutManager.setOrientation(LinearLayoutManager.VERTICAL);
    //mRecyclerView.setLayoutManager(mLayoutManager);
    viewPager.setAdapter(new PagerAdapter(getFragmentManager(), tabLayout.getTabCount()));
    viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
    tabLayout.setupWithViewPager(viewPager);
    tabLayout.setTabMode(TabLayout.MODE_SCROLLABLE);
    tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {

        @Override
        public void onTabSelected(TabLayout.Tab tab) {
            viewPager.setCurrentItem(tab.getPosition());
        }

        @Override
        public void onTabUnselected(TabLayout.Tab tab) {

        }

        @Override
        public void onTabReselected(TabLayout.Tab tab) {

        }
    });

    return view;
}

public class PagerAdapter extends FragmentStatePagerAdapter {
    int mNumOfTabs;

    public PagerAdapter(FragmentManager fm, int NumOfTabs) {
        super(fm);
        this.mNumOfTabs = NumOfTabs;
    }


    @Override
    public Fragment getItem(int position) {

        switch (position) {
            case 0:
              return new FragmentTab();
            case 1:
                return new FragmentTab();
            case 2:
                return new FragmentTab();

            default:
                return null;
        }
    }

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

FragmentTab pour chaque page dans View Pager (ou vous pouvez créer un fragment différent pour chaque page en fonction de vos besoins).

public class FragmentTab extends Fragment {
RecyclerView mRecyclerView;

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

    mRecyclerView = (RecyclerView) view.findViewById(R.id.recycler_view);
    LinearLayoutManager mLayoutManager = new LinearLayoutManager(getActivity());
    mLayoutManager.setOrientation(LinearLayoutManager.VERTICAL);
    mRecyclerView.setLayoutManager(mLayoutManager);
    RecyclerView.Adapter mAdapter = new AdapterOne();
    mRecyclerView.setAdapter(mAdapter);
    return view;
}
}

fragment_tab.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:Android="http://schemas.Android.com/apk/res/Android"
    Android:orientation="vertical" Android:layout_width="match_parent"
    Android:layout_height="match_parent">
    <Android.support.v7.widget.RecyclerView
        Android:id="@+id/recycler_view"
        Android:layout_width="match_parent"
        Android:layout_height="match_parent"
        />


</LinearLayout>
21
Aman Jain

Utilisez getChildFragmentManager() au lieu de getSupportFragmentManager()

4
madhu sudhan

Sans les journaux d'erreurs, il est difficile de dire où et pourquoi obtenez-vous la NullPointerException.

La première chose qui a attiré mon attention est que vous n'avez pas associé TabLayout à ViewPager Utilisez le code suivant après avoir défini l'adaptateur pour la ViewPager:

// setUpWithViewPager doesn't work without using a Runnable interface.
// Support library bug, maybe?
tabLayout.post(new Runnable() {
    @Override
    public void run() {
        tabLayout.setupWithViewPager(viewPager);
    }
});

Je ne suis pas sûr que ce soit le problème, mais essayez-le :)

2
adhirajsinghchauhan

je suggère d'utiliser getChildFragmentManager au lieu de getFragmentManager dans

viewPager.setAdapter(new PagerAdapter (getFragmentManager(), tabLayout.getTabCount()));

1
masoud vali

Eh bien, il y a quelque temps, j'ai implémenté exactement la même conception d'application. J'avais un fragment destiné à contenir des onglets et ViewPager. C’était une tâche délicate, et je me souviens que j’ai été confronté aux mêmes problèmes que vous. Voici comment je l'ai résolu:

La séquence de mise en page est la suivante: 

Activity -> Fragment -> Tab Layout + ViewPager -> FragmentStatePagerAdapter -> Fragment -> RecyclerView

Vous n'avez rien à voir avec votre activité principale. Tout le matériel est en fragments. Donc, débarrassez-vous de TabLayout dans votre activity_main.xml. 

Vous devrez faire face à des fragments imbriqués à l'intérieur du pager. Tout le contenu de la page doit être là et TabLayout doit être dans la même présentation que celle de ViewPager.  

Mon projet est un peu ancien et j'ai utilisé Android.support.v4.app.Fragment au cas où cela aurait du sens. J'ai supprimé les sources des données dont vous n’auriez pas besoin, vous pouvez donc voir des méthodes orphelines.

La tâche consistait à afficher la liste de prix avec les catégories et à restituer les produits de chaque catégorie sur sa propre page, de sorte que les balayages horizontaux permuteraient entre les catégories et les produits de liste de balayages verticaux. 

Chaque fragment avec ViewPager et TabLayout a la disposition subfragment_price_list_pager.xml suivante:

<?xml version="1.0" encoding="utf-8"?>
<Android.support.v7.widget.CardView 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:background="@color/icons"
    app:cardCornerRadius="4dp"
    app:cardElevation="4dp"
    app:cardPreventCornerOverlap="true">

    <Android.support.v7.widget.Toolbar
        Android:id="@+id/priceListToolbar"
        Android:layout_width="match_parent"
        Android:layout_height="wrap_content"
        Android:elevation="4dp"
        Android:theme="@style/AppTheme.Toolbar.TabLayout"
        app:navigationIcon="@drawable/ic_tag_multiple_grey600_24dp"
        tools:ignore="UnusedAttribute">

        <Android.support.design.widget.TabLayout
            Android:id="@+id/tabBar"
            Android:layout_width="match_parent"
            Android:layout_height="wrap_content"
            Android:layout_alignParentLeft="true"
            Android:layout_alignParentStart="true" />
    </Android.support.v7.widget.Toolbar>

    <Android.support.v4.view.ViewPager
        Android:id="@+id/priceList"
        Android:layout_width="match_parent"
        Android:layout_height="match_parent"
        Android:layout_marginTop="58dp"
        Android:padding="5dp"
        Android:scrollbars="horizontal" />


</Android.support.v7.widget.CardView>

Voici le PriceListPagerFragment.class:

public class PriceListPagerFragment extends Fragment {
    private static final String TAG = "PriceListPagerFragment";
    private PriceList mPriceList;

    private ViewPager mCategoriesViewPager;
    private TabLayout tabLayout;

    private Loader<PriceList> priceListLoader;
    private EditText scanerBarcodeText;
    private OnCartActionListener mListener;

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

        // Pager that would be inflated with page fragments.
        mCategoriesViewPager = (ViewPager) rootView.findViewById(R.id.priceList);
        tabLayout = (TabLayout) rootView.findViewById(R.id.tabBar);
        tabLayout.setTabMode(TabLayout.MODE_SCROLLABLE);

        // Do all the stuff with pager here:
        updatePriceListPages();

        return rootView;
    }


    private void updatePriceListPages() {
        if (mCategoriesViewPager != null && mPriceList != null) {
            Log.d(TAG, this + "updatePriceListPages");
            if (mCategoriesViewPager.getAdapter() == null) {


                PriceListCategoriesAdapter adapter = new PriceListCategoriesAdapter(
                        getFragmentManager(),
                        tabLayout
                );
                mCategoriesViewPager.setAdapter(
                        adapter
                );
                // Each page is a content of a single category of one-level catalog 
                // We did not supply catalog to adapter before it is bound to ViewPager for some serious reason which I can't recall now 
                adapter.setPriceList(mPriceList);

                tabLayout.setupWithViewPager(mCategoriesViewPager);
            } else {
                ((PriceListCategoriesAdapter) mCategoriesViewPager.getAdapter()).setPriceList(mPriceList);
            }
        }
    }
}

Implémentation FragmentStatePagerAdapter personnalisée, PriceListCategoriesAdapter.class:

public class PriceListCategoriesAdapter extends FragmentStatePagerAdapter {
    private static final String TAG = "PriceListCategoriesAd";
    private final TabLayout mTabLayout;
    private FragmentManager mFm;
    private Vector<PriceListFragment> recyclerViewList;
    private Vector<String> titles;

    public PriceListCategoriesAdapter(FragmentManager fm, TabLayout tabLayout) {
        super(fm);
        mFm = fm;
        mTabLayout = tabLayout;
        recyclerViewList = new Vector<>();
        titles = new Vector<>();
    }


    // All the magic with nested page fragments is done here
    public void setPriceList(PriceList priceList) {
        boolean updateTabs = false;

        Vector<String> newTitles = new Vector<>();

        int position = 0;
        for (CatalogItem catalogItem : priceList.getCatalogs()) {

            if (catalogItem.getProducts() == null)
                continue;

            boolean newFragment;

            PriceListFragment fragment;
            try {
                fragment = recyclerViewList.get(position);
                newFragment = false;

            } catch (ArrayIndexOutOfBoundsException e) {
                fragment = new PriceListFragment();
                newFragment = true;
            }

            fragment.setCatalogItem(catalogItem);

            newTitles.add(catalogItem.getName());

            if (newFragment) {
                recyclerViewList.add(fragment);
            }
            position++;
        }

        if (titles.size() != newTitles.size()) {
            updateTabs = true;
        } else {
            for (int position = 0; position < titles.size(); position++) {
                if (!titles.get(position).equals(newTitles.get(position))) {
                    updateTabs = true;
                    break;
                }
            }
        }

        titles = newTitles;
        notifyDataSetChanged();

        if (updateTabs)
            mTabLayout.setTabsFromPagerAdapter(this);
    }


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

    @Override
    public int getItemPosition(Object object) {
        PriceListFragment fragment = (PriceListFragment) object;
        String title = (String) fragment.getTitle();
        int position = titles.indexOf(title);

        if (position >= 0) {
            return position;
        } else {
            return POSITION_NONE;
        }
    }

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

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

    // We don't keep states
    @Override
    public Parcelable saveState() {
        return null;
    }
    // We don't keep states
    @Override
    public void restoreState(Parcelable state, ClassLoader loader) {
    }
}

Et enfin, PriceListFragment layout:

<?xml version="1.0" encoding="utf-8"?>
<Android.support.v7.widget.RecyclerView Android:id="@+id/categoryList"
    xmlns:Android="http://schemas.Android.com/apk/res/Android"
    Android:layout_width="match_parent"
    Android:layout_height="match_parent"
    Android:scrollbars="vertical" />

PriceListFragment.class lui-même n'a rien de spécial. Installez simplement RecyclerView avec les données appropriées. 

1
Клаус Шварц

Cette méthode getItem dans PagerAdapter faux, elle retourne Fragment initVous devriez retourner Fragment. Et par fragment, vous setViewrecyclerView

0
Phuoc Huynh