OnBackpressed get empty view on tablayout

OnBackpressed get empty view on tablayout - android

I am stuck in solving this problem. I have set tabs in fragment using TabLayout and ViewPager. The problem is when i move to next fragment and then i press back button i get empty tabs view.
Here I am attaching my code:
home.xml
<?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:gravity="center"
android:orientation="vertical">
<android.support.design.widget.TabLayout
android:id="#+id/tabLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="?attr/colorPrimary"
android:minHeight="?attr/actionBarSize"
android:theme="#style/ThemeOverlay.AppCompat.Dark.ActionBar"
app:tabIndicatorColor="#android:color/white"
app:tabIndicatorHeight="4dp" />
<android.support.v4.view.ViewPager
android:id="#+id/pager"
android:layout_width="match_parent"
android:layout_height="fill_parent" />
</LinearLayout>`
home.java(fragment)
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.home, container, false);
((Drawer) getActivity()).setActionBarTitle("Home");
Toast.makeText(getActivity(), "entry count" + getActivity().getSupportFragmentManager().getBackStackEntryCount(), Toast.LENGTH_SHORT).show();
tabLayout = (TabLayout) view.findViewById(R.id.tabLayout);
tabLayout.addTab(tabLayout.newTab().setText("Products"));
tabLayout.addTab(tabLayout.newTab().setText("Category"));
tabLayout.setTabGravity(TabLayout.GRAVITY_FILL);
viewPager = (ViewPager) view.findViewById(R.id.pager);
Pager adapter = new Pager(getActivity().getSupportFragmentManager(), tabLayout.getTabCount());
tabLayout.getTabCount());
viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
viewPager.setAdapter(adapter);
viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
tabLayout.setOnTabSelectedListener(this);
return view;
}
#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) {
}
pager.java (Adapter)
public class Pager extends FragmentStatePagerAdapter {
int tabCount;
public Pager(FragmentManager fm, int tabCount) {
super(fm);
this.tabCount = tabCount;
}
#Override
public Fragment getItem(int position) {
switch (position) {
case 0:
Product tab1 = new Product();
return tab1;
case 1:
Category tab2 = new Category();
return tab2;
default:
return null;
}
}
#Override
public int getCount() {
return tabCount;
}
}
MainActivity (where I set this tab fragment)
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_drawer);
getSupportActionBar().setTitle("Home");
fragment = new home();
FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
ft.replace(R.id.main, fragment);
ft.commit();

I had faced same issue when replacing fragment and that replaced fragment have TabLayout (i.e. Inner Fragments)
After researching about this issue: i found solution
What i does:
replacing
ViewPagerAdapter adapter = new ViewPagerAdapter(getActivity().getSupportFragmentManager());
to
If your Parent Activity is extending AppCompatActivity , then use
ViewPagerAdapter adapter = new ViewPagerAdapter(getChildFragmentManager());
If your Parent Activity is extending Activity than use
ViewPagerAdapter adapter = new ViewPagerAdapter(getActivity().getChildFragmentManager());

write you code in activity
#Override
public void onBackPressed() {
try {
if (getFragmentManager().getBackStackEntryCount() > 1) {
FragmentManager.BackStackEntry first = getFragmentManager().getBackStackEntryAt(0);
getFragmentManager().popBackStack(first.getId(), FragmentManager.POP_BACK_STACK_INCLUSIVE);
onNavigationItemSelected(navigationView.getMenu().getItem(0));
} else
finish();
} catch (Exception e) {
e.printStackTrace();
}
}

You do not need to attach PageListeners to tabLayout and tabListeners to ViewPager.
This will take care of this.
tabLayout.setupWithViewPager(viewPager);
Your updated code can be like this. Do tell me if you still face any problem.
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.home, container, false);
((Drawer) getActivity()).setActionBarTitle("Home");
Toast.makeText(getActivity(), "entry count" + getActivity().getSupportFragmentManager().getBackStackEntryCount(), Toast.LENGTH_SHORT).show();
tabLayout = (TabLayout) view.findViewById(R.id.tabLayout);
tabLayout.addTab(tabLayout.newTab().setText("Products"));
tabLayout.addTab(tabLayout.newTab().setText("Category"));
tabLayout.setTabGravity(TabLayout.GRAVITY_FILL);
viewPager = (ViewPager) view.findViewById(R.id.pager);
Pager adapter = new Pager(getActivity().getSupportFragmentManager(), tabLayout.getTabCount());
tabLayout.getTabCount());
//Link tabLayout with ViewPager.
tabLayout.setupWithViewPager(viewPager);
return view;
}

You should not create an Adapter inside a fragment with its activity's FragmentManager. Try to replace
Pager adapter = new Pager(getActivity().getSupportFragmentManager(), tabLayout.getTabCount());
with
Pager adapter = new Pager(getChildFragmentManager(), tabLayout.getTabCount());

Related

Tab doesn't take full width in fragment

I am trying to create tabs using fragment layout. It is not set the Full Width of the screen and also tabs text is not displaying. Didn't find any solution to fix this. Below I added my code and screenshots of the output and what I want to achieve, please check any help will be appreciated.
Main Activity
public class SettingActivity extends Fragment {
TabLayout tab;
ViewPager vp;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.activity_setting, container, false);
TabLayout tabLayout = (TabLayout) view.findViewById(R.id.tabs);
tabLayout.addTab(tabLayout.newTab());
tabLayout.addTab(tabLayout.newTab());
final ViewPager viewPager = (ViewPager) view.findViewById(R.id.vp);
viewPager.setAdapter(new ViewPagering(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;
}
}
ViewPager
public class ViewPagering extends FragmentStatePagerAdapter {
int noTabs;
private String[] tabTitles = new String[]{"Tab1", "Tab2"};
public ViewPagering(FragmentManager fm, int noTabs) {
super(fm);
this.noTabs = noTabs;
}
#Override
public CharSequence getPageTitle(int position) {
return tabTitles[position];
}
#Override
public Fragment getItem(int position) {
switch (position) {
case 0:
Frag1 f1 = new Frag1();
return f1;
case 1:
frag2 f2 = new frag2();
return f2;
default:
return null;
}
}
#Override
public int getCount() {
return noTabs;
}
}
Xml
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="rarecrew.com.taberp.SettingActivity">
<android.support.design.widget.TabLayout
android:id="#+id/tabs"
android:layout_width="match_parent"
android:layout_height="30dp"
app:tabMaxWidth="0dp"
app:tabMode="fixed"></android.support.design.widget.TabLayout>
<android.support.v4.view.ViewPager
android:id="#+id/vp"
android:layout_width="match_parent"
android:layout_height="match_parent"></android.support.v4.view.ViewPager>
</LinearLayout>
What I am getting
What I want to achieve

Tablayout inside Viewpager

I need to place TabLayout in ViewPager. ViewPager contains some fragments. I can't do it because TabLayout is located in my Activity and I can't manage it if it will be in Fragment.
Now my code looks like this. In Activity's XML:
<LinearLayout
...>
<android.support.v4.view.ViewPager
...>
</android.support.v4.view.ViewPager>
<android.support.design.widget.TabLayout
.../>
</LinearLayout>
and in Activity class
ViewPager mViewPager = (ViewPager) findViewById(R.id.view_pager_offer_detail);
TabLayout tabLayout = (TabLayout) findViewById(R.id.tabDots);
tabLayout.setupWithViewPager(mViewPager, true);
FragmentPagerAdapter mPagerAdapter = new FragmentPagerAdapter(...);
mViewPager.setAdapter(mPagerAdapter);
I need to get as shown below.
what i want (imgur doesn't work now)
Which version is correct and how to implement it in XML?

if I understand, you want to show some tabs (Fragments) inside your ViewPager right?
you can follow this implementation in your fragment:
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View inflatedView = inflater.inflate(R.layout.fragment_tablayout, container, false);
TabLayout tabLayout = (TabLayout) inflatedView.findViewById(R.id.tabLayout);
tabLayout.addTab(tabLayout.newTab().setText("Campusplan"));
tabLayout.addTab(tabLayout.newTab().setText("Raumplan"));
final ViewPager viewPager = (ViewPager) inflatedView.findViewById(R.id.viewpager);
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 inflatedView;
}
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:
TabItem1 tab1 = new TabItem1();
return tab1;
case 1:
TabItem1 tab2 = new TabItem1();
return tab2;
default:
return null;
}
}
#Override
public int getCount() {
return mNumOfTabs;
}
}
}
Put the tablayout and viewpager inside your layout.xml that represents your fragment as you do with a normal view.

TabLayout tabs text not displaying

I am using TabLayout inside a Fragment to display three fixed tabs and the tabs are working but it doesn't show the tab text even after I set the app:tabTextColor attribute in the layout it's still not visible.
NewFragment.java
public class NewFragment extends Fragment {
private RecyclerView mRecyclerView;
private RecyclerView.LayoutManager mLayoutManager;
private RecyclerView.Adapter mAdapter;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View inflatedView = inflater.inflate(R.layout.new_fragment, container, false);
TabLayout tabLayout = (TabLayout) inflatedView.findViewById(R.id.tabLayout);
tabLayout.addTab(tabLayout.newTab().setText("Tab 1"));
tabLayout.addTab(tabLayout.newTab().setText("Tab 2"));
tabLayout.addTab(tabLayout.newTab().setText("Tab 3"));
final ViewPager viewPager = (ViewPager) inflatedView.findViewById(R.id.viewpager);
LinearLayoutManager mLayoutManager = new LinearLayoutManager(getActivity());
mLayoutManager.setOrientation(LinearLayoutManager.VERTICAL);
viewPager.setAdapter(new PagerAdapter(getFragmentManager(), tabLayout.getTabCount()));
viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
tabLayout.setupWithViewPager(viewPager);
tabLayout.setTabMode(TabLayout.MODE_FIXED);
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 inflatedView;
}
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;
}
}
}
newfragment.xml
<android.support.design.widget.AppBarLayout 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"
tools:context=".NewFragment">
<android.support.design.widget.TabLayout
android:id="#+id/tabLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:tabMode="fixed"
app:tabTextColor="#ffffff"
app:tabGravity="fill"
app:theme="#style/ThemeOverlay.AppCompat.Dark.ActionBar"/>
<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.design.widget.AppBarLayout>

The problem is you're calling setupWithViewPager() after setting up your tabs with the addTab() calls, effectively overwriting them.
From the documentation of TabLayout regarding setupWithViewPager():
The tabs displayed in this
layout will be populated from the ViewPager adapter's page titles.
If you would like to use your TabLayout with a ViewPager, you should override getPageTitle() in your PagerAdapter (and remove the addTab() calls, they are redundant).
For example:
public class ExamplePagerAdapter extends FragmentStatePagerAdapter {
// tab titles
private String[] tabTitles = new String[]{"Tab1", "Tab2", "Tab3"};
public ExamplePagerAdapter(FragmentManager fm) {
super(fm);
}
// overriding getPageTitle()
#Override
public CharSequence getPageTitle(int position) {
return tabTitles[position];
}
#Override
public Fragment getItem(int position) {
switch (position) {
case 0:
return new Tab1Fragment();
case 1:
return new Tab2Fragment();
case 2:
return new Tab3Fragment();
default:
throw new RuntimeException("Invalid tab position");
}
}
#Override
public int getCount() {
return tabTitles.length;
}
// ...
}

i added tab text and icon for each tab after calling tabs.setupWithViewPager(viewPager)
viewPager.setAdapter(new MyViewAdapter(getSupportFragmentManager()));
TabLayout tabs=(TabLayout) findViewById(R.id.tabs);
tabs.setupWithViewPager(viewPager);
tabs.getTabAt(0).setIcon(R.drawable.icon1);
tabs.getTabAt(1).setIcon(R.drawable.icon2);
tabs.getTabAt(0).setText(getResources().getText(R.string.tab1));
tabs.getTabAt(1).setText(getResources().getText(R.string.tab2));

I'm using Kotlin and have spent an hour to find the bugs with this code.
var viewPager: ViewPager = view.findViewById(R.id.viewPager)
...
adapter = TabAdapter(fragmentManager!!)
adapter.addFragment(Fragment1(), "Fragment 1")
adapter.addFragment(Fragment2(), "Fragment 2")
viewPager.adapter = adapter
tabLayout.setupWithViewPager(viewpager)
I can compile this with no error, but the tab title is not showing until I realize the viewpager I assigned to the tabLayout is not viewPager (notice the capitalize 'P'). It's not producing error because kotlin will find any matching layout id, in this case "viewpager" which is a ViewPager but on another view.

I wanted to define TabItem in XML instead of doing it programmatically. As you mentioned, this setupWithViewPager() call resets the text and icon of the tab items to null( It uses the same tab object, just resets its content). I used your approach but made it more reusable. Here is my code:
public class TabLayoutUtil {
public static void setupTabLayoutWithViewPager(TabLayout tabLayout, ViewPager viewPager) {
ArrayList<Pair<CharSequence, Drawable>> tabsContentCopy= new ArrayList<>();
for (int i = 0; i < tabLayout.getTabCount(); i++) {
TabLayout.Tab tab = tabLayout.getTabAt(i);
tabsContentCopy.add(new Pair<>(tab != null ? tab.getText() : null, tab != null ? tab.getIcon() : null));
}
tabLayout.setupWithViewPager(viewPager);
for (int i = 0; i < tabLayout.getTabCount(); i++) {
if (i<tabsContentCopy.size()) {
tabLayout.getTabAt(i).setText(tabsContentCopy.get(i).first);
tabLayout.getTabAt(i).setIcon(tabsContentCopy.get(i).second);
}
}
}
}

Android: TabLayout not showing any tabs

First time working with com.android.support:design:23.1.1, and having some issues getting TabLayout to work.
My app is basically set up as such:
One main activity called LandingActivity which has a DrawerLayout with menu items in it.
When selecting a menu item, I load different Fragments into a FrameLayout in the LandingActivity.
Some of the loaded Fragments should show tabs at the top, some shouldn't.
My issue is, on the Fragment which is supposed to show tabs at the top, it has extra space in the nav bar like it should have tabs there, but nothing shows.
Code:
activity_landing.xml
<android.support.v4.widget.DrawerLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/drawer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent">
<!-- This LinearLayout represents the contents of the screen -->
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<!-- The ActionBar displayed at the top -->
<include
layout="#layout/tool_bar"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<!-- The main content view where fragments are loaded -->
<FrameLayout
android:id="#+id/flContent"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</LinearLayout>
<!-- The navigation drawer that comes from the left -->
<!-- Note that `android:layout_gravity` needs to be set to 'start' -->
<android.support.design.widget.NavigationView
android:id="#+id/nvView"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_gravity="start"
android:background="#android:color/white"
app:menu="#menu/drawer" />
LandingActivity where I load the fragments:
public void selectDrawerItem(MenuItem menuItem) {
// Create a new fragment and specify the planet to show based on
// position
Fragment fragment = null;
switch(menuItem.getItemId()) {
case R.id.drawer_home:
fragment = HomeFragment.newInstance();
break;
case R.id.drawer_customize:
fragment = CustomizeFragment.newInstance();
break;
default:
fragment = HomeFragment.newInstance();
}
// Insert the fragment by replacing any existing fragment
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager.beginTransaction().replace(R.id.flContent, fragment).commit();
home_fragment.xml (one which has tabs)
<android.support.design.widget.AppBarLayout 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:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.design.widget.TabLayout
android:id="#+id/tabLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:tabMode="fixed"
app:tabGravity="fill"
/>
<android.support.v4.view.ViewPager
android:id="#+id/viewpager"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#android:color/white"/>
HomeFragment.java
public class HomeFragment extends Fragment {
public static HomeFragment newInstance() {
Bundle args = new Bundle(); alreadySelectedFollowingInfo);
HomeFragment fragment = new HomeFragment();
fragment.setArguments(args);
return fragment;
}
public HomeFragment() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
final View v = inflater.inflate(R.layout.fragment_home, container, false);
final TabLayout tabLayout = (TabLayout) v.findViewById(R.id.tabLayout);
tabLayout.addTab(tabLayout.newTab().setText("One"));
tabLayout.addTab(tabLayout.newTab().setText("Two"));
final ViewPager viewPager = (ViewPager) v.findViewById(R.id.viewpager);
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) {
}
});
tabLayout.post(new Runnable() {
#Override
public void run() {
tabLayout.setupWithViewPager(viewPager);
}
});
return inflater.inflate(R.layout.fragment_home, container, false);
}
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:
BlogFragment tab1 = BlogFragment.newInstance();
return tab1;
case 1:
TrendingFragment tab2 = TrendingFragment.newInstance();
return tab2;
default:
return null;
}
}
#Override
public int getCount() {
return mNumOfTabs;
}
}
}
Might not be relevant, but tool_bar.xml used in activity_landing.xml
<android.support.v7.widget.Toolbar
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/toolbar"
android:layout_height="wrap_content"
android:layout_width="match_parent"
android:fitsSystemWindows="true"
android:minHeight="?attr/actionBarSize"
app:theme="#style/ThemeOverlay.AppCompat.Dark.ActionBar"
android:background="?attr/colorPrimary">
That's about all I've got. Can't figure out what's going on.
EDIT:
New code:
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
final View v = inflater.inflate(R.layout.fragment_home, container, false);
ViewPager viewPager = (ViewPager) v.findViewById(R.id.viewpager);
setupViewPager(viewPager);
TabLayout tabLayout = (TabLayout) v.findViewById(R.id.tabLayout);
tabLayout.setupWithViewPager(viewPager);
return v;
}
private void setupViewPager(ViewPager viewPager) {
PagerAdapter adapter = new PagerAdapter(getFragmentManager());
adapter.addFragment(BlogFragment.newInstance(), "ONE");
adapter.addFragment(TrendingFragment.newInstance(), "TWO");
viewPager.setAdapter(adapter);
}
class PagerAdapter extends FragmentPagerAdapter {
private final List<Fragment> mFragmentList = new ArrayList<>();
private final List<String> mFragmentTitleList = new ArrayList<>();
public PagerAdapter(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);
}
}

return inflater.inflate(R.layout.fragment_home, container, false);
in your onCreateView means that you return a newly inflated home fragment without any of your initialization code.
You should be returning the view that you created at the beginning of onCreateView:
return v;
Sample PagerAdapter that provides tab titles:
public class PagerAdapter extends FragmentPagerAdapter {
private final List<Fragment> mFragments = new ArrayList<>();
private final List<String> mFragmentTitles = new ArrayList<>();
public PagerAdapter(FragmentManager fm) {
super(fm);
}
public void addFragment(Fragment fragment, String title) {
mFragments.add(fragment);
mFragmentTitles.add(title);
}
#Override
public Fragment getItem(int position) {
return mFragments.get(position);
}
#Override
public int getCount() {
return mFragments.size();
}
#Override
public CharSequence getPageTitle(int position) {
return mFragmentTitles.get(position);
}
}
And so, your refactored onCreateView code would be something like:
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.fragment_home, container, false);
final TabLayout tabLayout = (TabLayout) v.findViewById(R.id.tabLayout);
final ViewPager viewPager = (ViewPager) v.findViewById(R.id.viewpager);
PagerAdapter adapter = new PagerAdapter(getFragmentManager());
adapter.addFragment(BlogFragment.newInstance(), "One");
adapter.addFragment(TrendingFragment.newInstance(), "Two");
viewPager.setAdapter(adapter);
tabLayout.post(new Runnable() {
#Override
public void run() {
tabLayout.setupWithViewPager(viewPager);
}
});
return v;
}

Return your initialized infleted view while you are returning
return inflater.inflate(R.layout.fragment_home, container, false);
while you should return view v from first line of onCreateView
final View v = inflater.inflate(R.layout.fragment_home, container, false);

How to set a ViewPager inside a Fragment

I need to place a ViewPager inside of a fragment, but I have two fragments, Fragment 1 is my MENU, and Fragment 2 I want to use as a ViewPagerIndicator.
But a fragment can't have another fragment... what do I need to do for that?

Starting in Android 4.2, there are nested fragments.http://developer.android.com/about/versions/android-4.2.html#NestedFragments The support library now also includes support for this for older Android versions.
So you can do something like this:
#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()));
}
Full implementation available here: https://github.com/marcoRS/nested-fragments/tree/master/src/com/burnside/digital/nestedfragments

You must use getChildFragmentManager() instead of getSupportFragmentManager() to get the FragmentManger inside a Fragment.
But you should not use FragmentStatePagerAdapter rather than FragmentPagerAdapter.

Just use getChildFragmentManager() instead of getSupportFragmentManager() inside Fragments.
Inside Fragments
new ViewPagerAdapter(getChildFragmentManager());
Inside Activity
new ViewPagerAdapter(getSupportFragmentManager());
Simple Code
fragment_sample.xml layout
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<com.google.android.material.tabs.TabLayout
android:id="#+id/tablayout"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<androidx.viewpager.widget.ViewPager
android:id="#+id/viewpager"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1" />
</LinearLayout>
SampleFragment.java class
public class SampleFragment extends Fragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View fragmentView = inflater.inflate(R.layout.fragment_sample, container, false);
return fragmentView;
}
#Override
public void onViewCreated(#NonNull View view, #Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
// find views by id
ViewPager viewPager = view.findViewById(R.id.viewpager);
TabLayout tabLayout = view.findViewById(R.id.tablayout);
// attach tablayout with viewpager
tabLayout.setupWithViewPager(viewPager);
ViewPagerAdapter adapter = new ViewPagerAdapter(getChildFragmentManager());
// add your fragments
adapter.addFrag(new SampleFragment(), "Tab1");
adapter.addFrag(new SampleFragment2(), "Tab2");
adapter.addFrag(new SampleFragment3(), "Tab3");
// set adapter on viewpager
viewPager.setAdapter(adapter);
}
}
ViewPagerAdapter.java class
// common adapter for all view pager in your project.
public class ViewPagerAdapter extends FragmentStatePagerAdapter {
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();
}
#Override
public CharSequence getPageTitle(int position) {
return mFragmentTitleList.get(position);
}
public void addFrag(Fragment fragment) {
mFragmentList.add(fragment);
mFragmentTitleList.add("");
}
public void addFrag(Fragment fragment, String title) {
mFragmentList.add(fragment);
mFragmentTitleList.add(title);
}
}
Important Related Links
Difference between getSupportFragmentManager() and getChildFragmentManager()?
getSupportFragmentManager() versus getFragmentManager() in android 3.0+
Difference between FragmentPagerAdapter and FragmentStatePagerAdapter

it is possible. try to do this code view_pager_fragment.xml file
<android.support.design.widget.AppBarLayout
android:id="#+id/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/tab"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</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" />
ViewPagerFragment
ViewPager viewPager;
TabLayout tabLayout;
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.tracks, container, false);
viewPager = (ViewPager) view.findViewById(R.id.viewpager);
tabLayout = (TabLayout) view.findViewById(R.id.tab);
return view;
}
#Override
public void onActivityCreated(#Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
setupViewPager(viewPager);
tabLayout.setupWithViewPager(viewPager);
tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
#Override
public void onTabSelected(TabLayout.Tab tab) {
}
#Override
public void onTabUnselected(TabLayout.Tab tab) {
}
#Override
public void onTabReselected(TabLayout.Tab tab) {
}
});
}
private void setupViewPager(ViewPager viewPager) {
ViewPagerAdapter viewPagerAdapter = new ViewPagerAdapter(getChildFragmentManager());``
viewPager.setAdapter(viewPagerAdapter);
}
private class ViewPagerAdapter extends FragmentPagerAdapter {
public ViewPagerAdapter(FragmentManager fragmentManager) {
super(fragmentManager);
}
#Override
public Fragment getItem(int position) {
if(position == 0) return new FirstFragment();
if(position == 1) return new SecoundFragment();
if(position == 2) return new LoginFragment();
throw new IllegalStateException("Position is unexpectedly " + position);
}
#Override
public int getCount() {
return 3;
}
#Override
public CharSequence getPageTitle(int position) {
if(position == 0) return "First";
if(position == 1) return "Secound";
if(position == 2) return "Login";
throw new IllegalStateException("Position is unexpectedly " + position);
}
}

With the Android Support V4 library, you can add a fragment inside another fragment. Try to use it, it may can resolve your problem.

After Read some examples, you cant have a FragmentActivity inside a fragmentActivity.
Is not necesary to have two fragments and this need be a FragmentPageAdapter... i only need to do this.
<android.support.v4.view.ViewPager
android:id="#+id/pager"
android:layout_width="match_parent"
android:layout_height="0px"
android:layout_weight="1" >
</android.support.v4.view.ViewPager>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="0"
android:gravity="center"
android:measureWithLargestChild="true"
android:orientation="horizontal" >
<Button
android:id="#+id/first"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="First" >
</Button>
<Button
android:id="#+id/last"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Last" >
</Button>
</LinearLayout>
Source:
http://www.truiton.com/2013/05/android-fragmentpageradapter-example/

Develop Reference

The Android operating system is a mobile operating system that was developed by Google (GOOGL?) to be primarily used for touchscreen devices, cell phones, and tablets.

OnBackpressed get empty view on tablayout - android

You should not create an Adapter inside a fragment with its activity's FragmentManager. Try to replace Pager adapter = new Pager(getActivity().getSupportFragmentManager(), tabLayout.getTabCount()); with Pager adapter = new Pager(getChildFragmentManager(), tabLayout.getTabCount());

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How to set a ViewPager inside a Fragment

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