Develop Reference

Replacement fragments in in pagerView

`Facing one problem in android that I created a pager View and two fragments lets say fragment A and fragment B are attached...
My question is: There is a button in fragment A after clicking on that button I want to load fragment C which will be the replacement of fragment A in the same pager view how can it be done? But when I try below code content of Fragment C is shown over the fragment A ... can u help me with this please. I searched everywhere but didn't get the proper solution.
here is my code...
public class MainActivity extends AppCompatActivity implements Top_Fragment.OnFragmentInteractionListener {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar=findViewById(R.id.tool_bar);
setSupportActionBar(toolbar);
MyPagerAdapter myPagerAdapter = new MyPagerAdapter(getSupportFragmentManager());
ViewPager viewPager = findViewById(R.id.pagerView);
viewPager.setAdapter(myPagerAdapter);
TabLayout tabLayout=findViewById(R.id.tab_bar);
tabLayout.setupWithViewPager(viewPager);
}
class MyPagerAdapter extends FragmentPagerAdapter {
public MyPagerAdapter(#NonNull FragmentManager fm) {
super(fm, BEHAVIOR_RESUME_ONLY_CURRENT_FRAGMENT);
}
#Override
public Fragment getItem(int position) {
switch (position) {
case 0:
return new Top_Fragment();
case 1:
return new FavoriteFrag();
}
return null;
}
#Override
public int getCount() {
return 2;
}
#Nullable
#Override
public CharSequence getPageTitle(int position) {
switch (position) {
case 0:
return getResources().getString(R.string.Items);
case 1:
return getResources().getString(R.string.favoriteItems);
}
return null;
}
}
#Override
public void onFragmentInteraction(int position) {
Fragment fragment=null;
switch (position){
case 0:
fragment=new DrikCategaryFrag();
}
FragmentTransaction ft=getSupportFragmentManager().beginTransaction();
ft.replace(R.id.frameContainer,fragment);
ft.commit();
}
}
Main activity layout
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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:orientation="vertical"
tools:context=".MainActivity">
<com.google.android.material.appbar.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="#style/ThemeOverlay.AppCompat.Dark.ActionBar">
<androidx.appcompat.widget.Toolbar
android:id="#+id/tool_bar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:theme="#style/ThemeOverlay.AppCompat.Dark.ActionBar" />
<com.google.android.material.tabs.TabLayout
android:id="#+id/tab_bar"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</com.google.android.material.appbar.AppBarLayout>
<FrameLayout
android:id="#+id/frameContainer"
android:layout_width="match_parent"
android:layout_height="match_parent">
<androidx.viewpager.widget.ViewPager
android:id="#+id/pagerView"
android:layout_width="match_parent"
android:layout_height="match_parent">
</androidx.viewpager.widget.ViewPager>
</FrameLayout>
</LinearLayout>

Try this:
Viewpager with multiple fragments:
public class MainActivity extends FragmentActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ViewPager pager = (ViewPager) findViewById(R.id.viewPager);
pager.setAdapter(new MyPagerAdapter(getSupportFragmentManager()));
}
private class MyPagerAdapter extends FragmentPagerAdapter {
public MyPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int pos) {
switch(pos) {
case 0: return FirstFragment.newInstance("FirstFragment, Instance 1");
case 1: return SecondFragment.newInstance("SecondFragment, Instance 1");
default: return FirstFragment.newInstance("FirstFragment, Default");
}
}
#Override
public int getCount() {
return 2;
}
}
}
activity_main.xml
<android.support.v4.view.ViewPager
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/viewPager"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
/>
FirstFragment.java
public class FirstFragment extends Fragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.first_frag, container, false);
TextView tv = (TextView) v.findViewById(R.id.tvFragFirst);
tv.setText(getArguments().getString("msg"));
return v;
}
public static FirstFragment newInstance(String text) {
FirstFragment f = new FirstFragment();
Bundle b = new Bundle();
b.putString("msg", text);
f.setArguments(b);
return f;
}
}
SecondFragment.java
public class SecondFragment extends Fragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.second_frag, container, false);
TextView tv = (TextView) v.findViewById(R.id.tvFragSecond);
tv.setText(getArguments().getString("msg"));
return v;
}
public static SecondFragment newInstance(String text) {
SecondFragment f = new SecondFragment();
Bundle b = new Bundle();
b.putString("msg", text);
f.setArguments(b);
return f;
}
}

Android tab layout broken scroll

Hi I have a small problem with the tab layout. After I have implemented tab layout and put the recycle view in I have the problem that after I scroll the list the toolbar seem to blend with the title. Am I making the mistake in the code tab activity or its some other issue.
Thanks
<android.support.design.widget.AppBarLayout
android:id="#+id/appbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:paddingTop="#dimen/appbar_padding_top"
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:layout_scrollFlags="scroll|enterAlways"
app:popupTheme="#style/AppTheme.PopupOverlay">
</android.support.v7.widget.Toolbar>
<android.support.design.widget.TabLayout
android:id="#+id/tabs"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</android.support.design.widget.AppBarLayout>
<android.support.v4.view.ViewPager
android:id="#+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior" />
Tab activity:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_completed__challenges);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
// Create the adapter that will return a fragment for each of the three
// primary sections of the activity.
mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
// Set up the ViewPager with the sections adapter.
mViewPager = (ViewPager) findViewById(R.id.container);
mViewPager.setAdapter(mSectionsPagerAdapter);
TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setupWithViewPager(mViewPager);
}
/**
* A {#link FragmentPagerAdapter} that returns a fragment corresponding to
* one of the sections/tabs/pages.
*/
public class SectionsPagerAdapter extends FragmentPagerAdapter {
public SectionsPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int position) {
switch (position){
case 0:
tab1_completed_running tab1 = new tab1_completed_running();
return tab1;
case 1:
tab2_completed_walking tab2 = new tab2_completed_walking();
return tab2;
case 2:
tab3_completed_cycling tab3 = new tab3_completed_cycling();
return tab3;
default:
return null;
}
}
#Override
public int getCount() {
// Show 3 total pages.
return 3;
}
#Override
public CharSequence getPageTitle(int position) {
switch (position) {
case 0:
return "Running";
case 1:
return "Walking";
case 2:
return "Cycling";
}
return null;
}
}
Layout of recycle view:
<android.support.v7.widget.RecyclerView
android:id="#+id/tab_resultList"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginTop="20dp">
</android.support.v7.widget.RecyclerView>

Replace fragment in fragment itself in TabActivity

I am sorry on the duplicate question but I didn't get answer for my problem.
I create app with TabActivity and also trying to replace one fragment from fragment itself, I read in https://developer.android.com/training/basics/fragments/fragment-ui.html how to do it and i created interface in my fragment that i want to be replace with another,
I implement the interface in my MainActivity and still when running my app it show me container itself.
here is my code:
Main Activity:
public class MainActivity extends FragmentActivity implements New2.OnReplaceFragment {
private SectionsPagerAdapter mSectionsPagerAdapter;
private ViewPager mViewPager;
public static MainActivity instance = null;
public static MainActivity getInstance(){
return instance;
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
mViewPager = (ViewPager) findViewById(R.id.frame_container);
mViewPager.setAdapter(mSectionsPagerAdapter);
TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setupWithViewPager(mViewPager);
tabLayout.getTabAt(0).setIcon(R.drawable.icon_info);
tabLayout.getTabAt(1).setIcon(R.drawable.icon_heart_rate_sensor_jpg);
tabLayout.getTabAt(2).setIcon(R.drawable.icon_graph_jpg);
instance = this;
}
#Override
public void onReplaceFragment(Class fragmentClass) {
Fragment fragment = null;
try {
fragment = (Fragment) fragmentClass.newInstance();
} catch (Exception e) {
e.printStackTrace();
}
// Insert the fragment by replacing any existing fragment
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.frame_container,fragment);
// Replace whatever is in the fragment_container view with this fragment,
// and add the transaction to the back stack so the user can navigate back
transaction.addToBackStack(null);
// Commit the transaction
transaction.commit();
}
public static class PlaceholderFragment extends Fragment {
/**
* The fragment argument representing the section number for this
* fragment.
*/
private static final String ARG_SECTION_NUMBER = "section_number";
public PlaceholderFragment() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container, false);
TextView textView = (TextView) rootView.findViewById(R.id.section_label);
textView.setText(getString(R.string.section_format, getArguments().getInt(ARG_SECTION_NUMBER)));
return rootView;
}
}
public class SectionsPagerAdapter extends FragmentPagerAdapter {
public SectionsPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int position) {
// getItem is called to instantiate the fragment for the given page.
// Return a PlaceholderFragment (defined as a static inner class below).
switch (position) {
case 0:
// New1 tab1 = new New1();
return New1.newInstance();
case 1:
return New2.newInstance();
case 2:
return New3.newInstance();
default:
return null;
}
}
#Override
public int getCount() {
// Show 3 total pages.
return 3;
}
#Override
public CharSequence getPageTitle(int position) {
switch (position) {
case 0:
return "SECTION 1";
case 1:
return "SECTION 2";
case 2:
return "SECTION 3";
}
return null;
}
}
}
my fragment that I want to replace
Fragment:
public class New2 extends Fragment {
TextView name;
Button change;
ImageView image1;
Animation anime;
private OnReplaceFragment dataPasser;
public static New2 newInstance(){
New2 fragment = new New2();
return fragment;
}
public New2(){
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_new2, container, false);
name = (TextView) rootView.findViewById(R.id.nameTt);
change = (Button) rootView.findViewById(R.id.changeBtn);
image1 = (ImageView) rootView.findViewById(R.id.image1);
anime = AnimationUtils.loadAnimation(getActivity().getApplicationContext(),R.anim.zoom);
change.setOnClickListener(changeName);
return rootView;
}
View.OnClickListener changeName = new View.OnClickListener() {
#Override
public void onClick(View view) {
image1.startAnimation(anime);
Handler handler = new Handler();
handler.postDelayed(new Runnable() {
#Override
public void run(){
dataPasser.onReplaceFragment(Result.class);
}
},1000);
}
};
public interface OnReplaceFragment {
public void onReplaceFragment(Class fragmentClass);
}
#Override
public void onAttach(Activity a) {
super.onAttach(a);
try {
dataPasser = (OnReplaceFragment) a;
} catch (ClassCastException e) {
throw new ClassCastException(a.toString() + " must implement onDataPass");
}
}
}
the fragment that i want to display
public class Result extends Fragment {
TextView textView;
Button btnBack;
public static Result instance = null;
public static Result getInstance(){
return instance;
}
public Result() {
// Required empty public constructor
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View v = inflater.inflate(R.layout.fragment_result, container, false);
textView = (TextView) v.findViewById(R.id.text11);
btnBack = (Button) v.findViewById(R.id.btnBack);
textView.setText("working!!");
Toast.makeText(getActivity().getApplicationContext(),"working",Toast.LENGTH_LONG).show();
return v;
}
}
Main Activity 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:id="#+id/main_content"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
tools:context="com.example.hercules.tadhosttutrial.MainActivity">
<android.support.design.widget.AppBarLayout
android:id="#+id/appbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:paddingTop="#dimen/appbar_padding_top"
android:background="#color/red"
android:theme="#style/AppTheme.AppBarOverlay">
<android.support.design.widget.TabLayout
android:id="#+id/tabs"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</android.support.design.widget.AppBarLayout>
<android.support.v4.view.ViewPager
android:id="#+id/frame_container"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior" />
New2 XML:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.hercules.tadhosttutrial.New2"
android:background="#color/yellow">
<!-- TODO: Update blank fragment layout -->
<Button
android:id="#+id/changeBtn"
android:layout_width="80dp"
android:layout_height="40dp"
android:layout_gravity="center_horizontal"
android:text="change"/>
<ImageView
android:id="#+id/image1"
android:background="#drawable/icon_complete"
android:layout_width="200dp"
android:layout_height="200dp"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
/>
Result XML:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#color/colorAccent"
tools:context="com.example.hercules.tadhosttutrial.Result">
<!-- TODO: Update blank fragment layout -->
<Button
android:id="#+id/btnBack"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="back"/>
<TextView
android:id="#+id/text11"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="WORKING"
android:layout_centerVertical="true"
android:layout_centerHorizontal="true"
android:textSize="70dp"
/>
</RelativeLayout>

What i mean, is making MainActivity as a main container for all fragments, either with tabs or just a regular fragment,
1- Main Activity XML: remove ViewPager, add a FrameLayout instead (use same id)
2- Create new fragment TabsFragment with this XML:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.hercules.tadhosttutrial.New2"
android:background="#color/yellow">
<android.support.v4.view.ViewPager
android:id="#+id/frame_container"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior" />
</RelativeLayout>
3- Move initializing SectionsPagerAdapter and ViewPager from main activity to TabsFragment:
this part:
private SectionsPagerAdapter mSectionsPagerAdapter;
private ViewPager mViewPager;
and this:
mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
mViewPager = (ViewPager) findViewById(R.id.frame_container);
mViewPager.setAdapter(mSectionsPagerAdapter);
TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setupWithViewPager(mViewPager);
tabLayout.getTabAt(0).setIcon(R.drawable.icon_info);
tabLayout.getTabAt(1).setIcon(R.drawable.icon_heart_rate_sensor_jpg);
tabLayout.getTabAt(2).setIcon(R.drawable.icon_graph_jpg);
4- I think moving SectionsPagerAdapter class in a new file is better too.
now if you want default view for app to be the tabs, then in MainActivity at onCreate() show TabsFragment by calling your method:
onReplaceFragment(TabsFragment.class);
now every thing should work fine, because the idea here is to replace the fragment displayed in main activity with another one
in this case TabsFragment, Result, and New2
not to replace viewpager fragments (because as i told you this is managed via the adapter) not by calling replace()
you may need to play around this, it's not a final code, just something to give you idea about it.

TabLayout - ViewPager - Fragment

I have a problem with my ViewPager and fragments it contains. I have 2 menus (A and B), my homepage is directly A. When I click on a menu B fragment which contains a TabLayout, which contains a ViewPager himself three fragments (each contains a simple TextView with Lorem ipsum).
The 3 fragments of ViewPager are correct but if I click on the menu A and I click again on the menu B I do not have any content. Nothing on the fragments 1 and 2 against with the 3rd still has the text and if I return to fragment 1 reads income (for nothing against the fragment 2).
Here is my code :
Menu B (FragmentTabLayout)
public class TabLayoutFragment extends Fragment {
private static final String ARG_TEXT = "ARG_TEXT";
private static final String ARG_COLOR = "ARG_COLOR";
private Toolbar toolbar;
private TabLayout tabLayout;
private ViewPager viewPager;
public TabLayoutFragment() {
// Required empty public constructor
}
public static TabLayoutFragment newInstance(String text, int color) {
Bundle args = new Bundle();
args.putString(ARG_TEXT, text);
args.putInt(ARG_COLOR, color);
TabLayoutFragment tabLayoutFragment = new TabLayoutFragment();
tabLayoutFragment.setArguments(args);
return tabLayoutFragment;
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
setHasOptionsMenu(true);
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_tab_layout, container, false);
toolbar = (Toolbar) view.findViewById(R.id.toolbar);
((AppCompatActivity)getActivity()).setSupportActionBar(toolbar);
toolbar.setBackgroundColor(getArguments().getInt(ARG_COLOR));
toolbar.setTitle(getArguments().getString(ARG_TEXT));
viewPager = (ViewPager) view.findViewById(R.id.viewpager);
setupViewPager(viewPager);
tabLayout = (TabLayout) view.findViewById(R.id.tabs);
tabLayout.setupWithViewPager(viewPager);
tabLayout.setBackgroundColor(getArguments().getInt(ARG_COLOR));
tabLayout.setSelectedTabIndicatorColor(Color.WHITE);
return view;
}
#Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
inflater.inflate(R.menu.tab_menu, menu);
super.onCreateOptionsMenu(menu, inflater);
}
private void setupViewPager(ViewPager viewPager) {
ViewPagerAdapter adapter = new ViewPagerAdapter(getActivity().getSupportFragmentManager());
viewPager.setAdapter(adapter);
}
class ViewPagerAdapter extends FragmentPagerAdapter {
//private final List<TabFragment> mFragmentList = new ArrayList<>();
//private final List<String> mFragmentTitleList = new ArrayList<>();
public ViewPagerAdapter(FragmentManager manager) {
super(manager);
}
#Override
public Fragment getItem(int position) {
switch (position) {
case 0:
return TabFragment.newInstance("Fragment 2-1");
case 1:
return TabFragment.newInstance("Fragment 2-2");
case 2:
return TabFragment.newInstance("Fragment 2-3");
default:
return TabFragment.newInstance("Fragment Default");
}
}
#Override
public int getCount() {
//return mFragmentList.size();
return 3;
}
}
}
Fragment in ViewPager :
public class TabFragment extends Fragment {
private static final String ARG_TEXT = "ARG_TEXT";
private TextView tv;
public TabFragment() {
// Required empty public constructor
}
public static TabFragment newInstance(String text) {
Bundle args = new Bundle();
args.putString(ARG_TEXT, text);
TabFragment tabFragment= new TabFragment();
tabFragment.setArguments(args);
return tabFragment;
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_tab, container, false);
tv = (TextView) view.findViewById(R.id.tv);
return view;
}
}
Layout FragmentTabLayout :
<android.support.design.widget.CoordinatorLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<android.support.design.widget.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="#style/ThemeOverlay.AppCompat.Dark.ActionBar">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:layout_scrollFlags="scroll|enterAlways"
app:popupTheme="#style/ThemeOverlay.AppCompat.Light" />
<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="match_parent"
/>
</android.support.design.widget.CoordinatorLayout>
layout tabFragment :
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:orientation="vertical"
tools:context="com.application.myapplication.TabFragment">
<android.support.v4.widget.NestedScrollView
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
>
<TextView
android:id="#+id/tv"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="#string/lorem_ipsum"
/>
</android.support.v4.widget.NestedScrollView>
</LinearLayout>

you can extends your ViewPagerAdapter
FragmentStatePagerAdapter
instead of
FragmentPagerAdapter
I have same issue and it works for me.

In my Opinion the better approach is you should try using childFragmentManager for your nested fragments
Here is the simple example:
private void setupViewPager(ViewPager viewPager) {
ViewPagerAdapter adapter = new ViewPagerAdapter(getActivity().getChildFragmentManager());
viewPager.setAdapter(adapter);
}
Hopefully it will solve your issue.

Can a fragment be a host to a view pager instead of an activity?

Can a view pager be put in a fragment's layout, so this fragment would be the host to a few other fragments? So far I've seen only Activities as a host.

Yes, you can, use the code bellow
#Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
ViewPager mViewPager = (ViewPager) view.findViewById(R.id.viewPager);
mViewPager.setAdapter(new MyAdapter(getChildFragmentManager()));
}
view the full implementation here https://github.com/marcoRS/nested-fragments/tree/master/src/com/burnside/digital/nestedfragments

Yes, it is possible.
Here is an example (Use TabHost inside a Fragment with a ViewPager):
public class GroupFragment extends Fragment {
private static TabLayout tabLayout;
private static ViewPager viewPager;
private static final int int_items = 4 ;
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View x = inflater.inflate(R.layout.tab_layout,null);
tabLayout = (TabLayout) x.findViewById(R.id.tabs);
viewPager = (ViewPager) x.findViewById(R.id.viewpager);
viewPager.setAdapter(new MyAdapter(getChildFragmentManager()));
tabLayout.post(new Runnable() {
#Override
public void run() {
tabLayout.setupWithViewPager(viewPager);
}
});
return x;
}
class MyAdapter extends FragmentPagerAdapter{
public MyAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int position){
switch (position){
case 0 : return new PrimaryFragment();
case 1 : return new SocialFragment();
case 2 : return new UpdatesFragment();
case 3 : return new TeamFragment();
}
return null;
}
#Override
public int getCount() {
return int_items;
}
#Override
public CharSequence getPageTitle(int position) {
switch (position){
case 0 :
return "Grupo A";
case 1 :
return "Grupo B";
case 2 :
return "Grupo C";
case 3:
return "Grupo D";
}
return null;
}
}
}
And the Layout of the fragment is this:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:orientation="vertical"
android:layout_height="wrap_content">
<android.support.design.widget.TabLayout
android:id="#+id/tabs"
app:tabGravity="fill"
app:tabMode="fixed"
android:layout_width="match_parent"
android:layout_height="wrap_content">
</android.support.design.widget.TabLayout>
<android.support.v4.view.ViewPager
android:id="#+id/viewpager"
android:layout_width="match_parent"
android:layout_height="match_parent">
</android.support.v4.view.ViewPager>
</LinearLayout>
I hope that helps.