Android Fragment内のTabLayout
使っています Navigation Drawerフラグメント間を移動するには、すべてMainActivityツールバーを使用しますが、各フラグメントには独自のTabLayoutがあり、3つのタブがあり、各タブでRecyclerViewを使用して異なるテキストと画像を表示します。
フラグメントの代わりにアクティビティを使用してこれを最後に行いましたが、ドロワーを使用してフラグメントを使用するのがベターです。
タブが機能するポイントに到達しましたが、ViewPagerを挿入してアダプターをタブに接続し、ドロワーから新しいフラグメントを開くとすぐに、問題の可能性のあるNullポインターを取得しますここに？
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>
エラーログ
--------- 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)
あなたのコードを調べた後、FragmentStatePagerAdapterからオーバーライドしたPagerAdapterのgetItemメソッドでフラグメントを返すのを忘れていることがわかりました。返されました。
そのためには、ViewPagerの各ページに別の新しいフラグメントを作成するか、ViewPagerのすべてのページで使用できる新しいフラグメントを1つ作成する必要があります。
親フラグメントで定義したビューページャーのタブに同じrecyclerviewを使用することはできません。
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>
フラグメントを修正し、ViewPagerページで使用できる新しいフラグメントを作成しました。
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;
}
}
}
View Pagerの各ページのFragmentTab（または、必要に応じて各ページに異なるフラグメントを作成できます）。
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>
getChildFragmentManager()の代わりにgetSupportFragmentManager()を使用します
エラーログがなければ、NullPointerExceptionを取得する場所と理由を特定することは困難です。
私の注意を引いた最初のことは、TabLayoutとViewPagerをリンクしなかったことです。 ViewPagerのアダプターを設定した後、次のコードを使用します。
// setUpWithViewPager doesn't work without using a Runnable interface.
// Support library bug, maybe?
tabLayout.post(new Runnable() {
@Override
public void run() {
tabLayout.setupWithViewPager(viewPager);
}
});
これが問題かどうかはわかりませんが、試してみてください:)
getChildFragmentManagerの代わりにgetFragmentManagerを使用することをお勧めします
viewPager.setAdapter(new PagerAdapter (getFragmentManager(), tabLayout.getTabCount()));
さて、しばらく前に、まったく同じアプリ設計を実装しました。 TabsとViewPagerを保持するためのフラグメントがありました。それはトリッキーな仕事であり、あなたと同じような問題に直面したことを思い出します。ここに私がそれを解決した方法があります：
レイアウトシーケンスは次のとおりです。
Activity -> Fragment -> Tab Layout + ViewPager -> FragmentStatePagerAdapter -> Fragment -> RecyclerView
メインアクティビティとは何の関係もありません。すべてのものは断片になっています。 activity_main.xmlのTabLayoutを削除してください。
ページャー内のネストされたフラグメントを処理する必要があります。すべてのページコンテンツが存在し、TabLayoutはViewPagerと同じレイアウトにある必要があります。
私のプロジェクトは少し古く、意味がある場合に備えてAndroid.support.v4.app.Fragmentを使用しました。必要のないデータからソースを削除したので、いくつかの孤立したメソッドを参照することがあります。
タスクは、価格表にカテゴリを表示し、各カテゴリの製品を独自のページにレンダリングして、水平方向のスワイプでカテゴリと垂直方向のスワイプを切り替えて製品をリストすることでした。
ViewPagerおよびTabLayoutを含む各フラグメントには、次のsubfragment_price_list_pager.xmlレイアウトがあります。
<?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>
PriceListPagerFragment.classは次のとおりです。
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);
}
}
}
}
カスタムFragmentStatePagerAdapter実装、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) {
}
}
そして最後にPriceListFragmentレイアウト：
<?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自体には特別なものはありません。適切なデータでRecyclerViewをインスタンス化するだけです。
このメソッドgetItem in PagerAdapterは間違っています。Fragment initを返しますFragmentを返す必要があります。そして、フラグメントでは、setViewrecyclerView