Develop Reference

How to set Image/Icon in Tabs instead of Text?

I want to set image/icon in Tabsin the following code:
in my application i set Tabs in Bottom and now i want to set image in the space of the text.. i tried tutorials also but not getting output as i wanted to
Here Tab.xml
<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"
tools:context=".MainActivity"
android:orientation="vertical">
<android.support.v4.view.ViewPager
android:id="#+id/viewpager"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
android:background="#color/white"/>
<android.support.design.widget.TabLayout
android:id="#+id/sliding_tabs"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#color/orange"
/>
</LinearLayout>
Now Tab.Java
package com.example.sachin.navigationwithswipe;
import android.content.Intent;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.design.widget.TabLayout;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TabHost;
public class TabFragment extends Fragment {
public static TabLayout tabLayout;
public static ViewPager viewPager;
public static int int_items = 3 ;
#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.sliding_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);
}
/**
* Return fragment with respect to Position .
*/
#Override
public Fragment getItem(int position)
{
switch (position){
case 0 : return new PrimaryFragment();
case 1 : return new SocialFragment();
case 2 : return new UpdatesFragment();
}
return null;
}
#Override
public int getCount() {
return int_items;
}
/**
* This method returns the title of the tab according to the position.
*/
#Override
public CharSequence getPageTitle(int position) {
switch (position){
case 0 :
return "Primary";
case 1 :
return "Social";
case 2 :
return "Updates";
}
return null;
}
}
}
i want to set Image in the Tabs using following code.

Use this to set icon in tab
tabLayout.setupWithViewPager(viewPager);
//You tab icons
private int[] icons = {
R.drawable.one,
R.drawable.two,
R.drawable.three
};
for (int i = 0; i < tabLayout.getTabCount(); i++) {
tabLayout.getTabAt(i).setIcon(icons[i]);
}
Also If you want only Icon then on Adapter pass pageTitle null
#Override
public CharSequence getPageTitle(int position) {
// return null to display only the icon
return null;
}
Use this for Selector. This Might Work
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:drawable="#drawable/icon_on" android:state_selected="true"/>
<item android:drawable="#drawable/icon_off"/> <!-- default -->
</selector>

Set icon like this way..
mTabLayout.addTab(mTabLayout.newTab().setIcon(R.drawable.yourIcon));

To set both icon and text:
public class MainActivity extends AppCompatActivity {
private Toolbar toolbar;
private TabLayout tabLayout;
private ViewPager viewPager;
private int[] tabIcons = {
R.drawable.ic_tab_favourite,
R.drawable.ic_tab_call,
R.drawable.ic_tab_contacts
};
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
viewPager = (ViewPager) findViewById(R.id.viewpager);
setupViewPager(viewPager);
tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setupWithViewPager(viewPager);
setupTabIcons();
}
private void setupTabIcons() {
tabLayout.getTabAt(0).setIcon(tabIcons[0]);
tabLayout.getTabAt(1).setIcon(tabIcons[1]);
tabLayout.getTabAt(2).setIcon(tabIcons[2]);
}
private void setupViewPager(ViewPager viewPager) {
ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager());
adapter.addFrag(new OneFragment(), "ONE");
adapter.addFrag(new TwoFragment(), "TWO");
adapter.addFrag(new ThreeFragment(), "THREE");
viewPager.setAdapter(adapter);
}
class ViewPagerAdapter extends FragmentPagerAdapter {
private final List<Fragment> mFragmentList = new ArrayList<>();
private final List<String> mFragmentTitleList = new ArrayList<>();
public ViewPagerAdapter(FragmentManager manager) {
super(manager);
}
#Override
public Fragment getItem(int position) {
return mFragmentList.get(position);
}
#Override
public int getCount() {
return mFragmentList.size();
}
public void addFrag(Fragment fragment, String title) {
mFragmentList.add(fragment);
mFragmentTitleList.add(title);
}
#Override
public CharSequence getPageTitle(int position) {
return mFragmentTitleList.get(position);
}
}
}
Setting only icon to tab is same as setting text and icon except the method getPageTitle() in ViewPagerAdapter class returns null instead of tab label.
Modify MainActivity.java and modify the getPageTitle() method as :
#Override
public CharSequence getPageTitle(int position) {
// return null to display only the icon
return null;
}

How to switch between two fragments in android TabLayout?

how to switch between Fragment A and Fragment B in android TabLayout.
how to switch to next Fragment when Fargment Button Onclick is called.
Please help me
package com.digi.global.globalhub.fragment.offer;
import android.content.Context;
import android.graphics.Color;
import android.graphics.PorterDuff;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.support.design.widget.TabLayout;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentStatePagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.PopupMenu;
import android.support.v7.widget.Toolbar;
import android.view.LayoutInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import com.digi.global.globalhub.R;
import com.digi.global.globalhub.Utility.M;
import com.digi.global.globalhub.listener.FilterListener;
import com.digi.global.globalhub.listener.FragmentMove;
import com.digi.global.globalhub.listener.OfferFilter;
public class OfferFragmentActivity extends Fragment implements View.OnClickListener{
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";
private String mParam1;
private String mParam2;
PagerAdapter adapter;
ViewPager viewPager;
TabLayout tabLayout;
Context context;
Toolbar toolbar;
ImageView bizMenu;
PopupMenu popup;
public static OfferFragmentActivity mInstance = null;
public OfferFragmentActivity() {
// Required empty public constructor
}
public static OfferFragmentActivity newInstance(String param1, String param2) {
OfferFragmentActivity fragment = new OfferFragmentActivity();
Bundle args = new Bundle();
args.putString(ARG_PARAM1, param1);
args.putString(ARG_PARAM2, param2);
fragment.setArguments(args);
return fragment;
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getArguments() != null) {
mParam1 = getArguments().getString(ARG_PARAM1);
mParam2 = getArguments().getString(ARG_PARAM2);
}
context = this.getContext();
mInstance = this;
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
final View view =inflater.inflate(R.layout.fragment_offer, container, false);
viewPager = (ViewPager) view.findViewById(R.id.viewpager);
adapter = new PagerAdapter(getChildFragmentManager(), getContext());
tabLayout = (TabLayout) view.findViewById(R.id.tablayout);
viewPager.setAdapter(adapter);
tabLayout.setupWithViewPager(viewPager);
toolbar = (Toolbar) view.findViewById(R.id.toolbar);
bizMenu = (ImageView) view.findViewById(R.id.bizMenu);
bizMenu.setVisibility(View.VISIBLE);
bizMenu.setOnClickListener(this);
((AppCompatActivity)getActivity()).setSupportActionBar(toolbar);
//toolbar.setNavigationIcon(getResources().getDrawable(R.drawable.biz_ic, android.R.style.Theme_DeviceDefault));
((AppCompatActivity)getActivity()).getSupportActionBar().setDisplayShowHomeEnabled(true);
((AppCompatActivity)getActivity()).getSupportActionBar().setDisplayHomeAsUpEnabled(true);
final Drawable upArrow = getResources().getDrawable(R.mipmap.ic_menu_white_36dp);
upArrow.setColorFilter(Color.parseColor("#B68426"), PorterDuff.Mode.SRC_ATOP);
((AppCompatActivity)getActivity()).getSupportActionBar().setHomeAsUpIndicator(upArrow);
((AppCompatActivity)getActivity()).getSupportActionBar().setTitle(getString(R.string.Offers));
viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
#Override
public void onTabSelected(final TabLayout.Tab tab) {
viewPager.setCurrentItem(tab.getPosition());
}
#Override
public void onTabUnselected(TabLayout.Tab tab) {
}
#Override
public void onTabReselected(TabLayout.Tab tab) {
}
});
return view;
}
#Override
public void onClick(View v) {
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
Fragment fragment = (Fragment) adapter.instantiateItem(viewPager, viewPager.getCurrentItem());
if(fragment instanceof OfferFilter){
switch (item.getItemId()) {
case R.id.bizTravel:
((OfferFilter) fragment).onFilterBizTravel("bizTravel");
return true;
case R.id.bizAssistance:
((OfferFilter) fragment).onFilterAssistance("bizAssistance");
return true;
case R.id.bizSolution:
((OfferFilter) fragment).onFilterSolution("bizSolution");
return true;
case R.id.partners:
((OfferFilter) fragment).onFilterPartner("partners");
return true;
case R.id.favoutites:
((OfferFilter) fragment).onFilterFavouritesBiz("favoutites");
return true;
}
return false;
}
return super.onOptionsItemSelected(item);
}
class PagerAdapter extends FragmentStatePagerAdapter {
String tabTitles[] = getResources().getStringArray(R.array.offerTab);
Context context;
public PagerAdapter(FragmentManager fm, Context context) {
super(fm);
this.context = context;
}
#Override
public int getCount() {
return tabTitles.length;
}
#Override
public Fragment getItem(int position) {
/* FragmentMove fragmentChanges = (FragmentMove) adapter.instantiateItem(viewPager, 2);
if(fragmentChanges instanceof FragmentMove) {
((FragmentMove) fragmentChanges).fragmentChanges();
}*/
switch (position) {
case 0:
return new FragmentOne();
case 1:
return new FragmentTWO();
case 2:
return new FragmentThree();
}
return null;
}
#Override
public CharSequence getPageTitle(int position) {
return tabTitles[position];
}
/* public View getTabView(int position) {
View tab = LayoutInflater.from(getContext()).inflate(R.layout.tab_text_layout, null);
TextView tv = (TextView) tab.findViewById(R.id.tabText);
tv.setText(tabTitles[position]);
return tab;
}*/
}
}

You can have a FragmentPagerAdapter to manager fragments and set this adapter into viewPager to slide fragments when you click on tabs or swipe to change tabs.
FragmentPagerAdapter:
public class TabLayoutViewPagerAdapter extends FragmentPagerAdapter {
private final int PAGE_COUNT = 3;
private final String[] mTabsTitle = {"Fragment A", "Fragment B, "Fragment C"};
private Context context;
private int[] mTabsIcons = {
R.drawable.a,
R.drawable.b,
R.drawable.c};
public TabLayoutViewPagerAdapter(FragmentManager fm, Context context) {
super(fm);
this.context = context;
}
public View getTabView(int position) {
View view = LayoutInflater.from(context).inflate(R.layout.custom_tab, null);
TextView title = (TextView) view.findViewById(R.id.title);
title.setText(mTabsTitle[position]);
title.setSingleLine(true);
ImageView icon = (ImageView) view.findViewById(R.id.icon);
icon.setImageResource(mTabsIcons[position]);
return view;
}
#Override
public Fragment getItem(int pos) {
switch (pos) {
case 0:
return new FragmentA();
case 1:
return new FragmentB();
case 2:
return new FragmentC();
}
return null;
}
#Override
public int getCount() {
return PAGE_COUNT;
}
#Override
public CharSequence getPageTitle(int position) {
return mTabsTitle[position];
}}
How you use it:
ViewPager viewPager = (ViewPager) findViewById(R.id.viewPager);
TabLayoutViewPagerAdapter pagerAdapter = new TabLayoutViewPagerAdapter(getSupportFragmentManager(), this);
if (viewPager != null) {
viewPager.setAdapter(pagerAdapter);
}
You need a TabLayout:
mTabLayout = (TabLayout) findViewById(R.id.tabLayout);
if (mTabLayout != null) {
mTabLayout.setupWithViewPager(viewPager);
//populate your tabs
for (int i = 0; i < mTabLayout.getTabCount(); i++) {
TabLayout.Tab tab = mTabLayout.getTabAt(i);
if (tab != null)
tab.setCustomView(pagerAdapter.getTabView(i));
}
TabLayout.Tab tab = mTabLayout.getTabAt(0);
if (tab != null && tab.getCustomView() != null) {
tab.getCustomView().setSelected(true);
}
}
How to select a page:
private void selectPage(int pageIndex) {
mTabLayout.setScrollPosition(pageIndex, 0f, true);
viewPager.setCurrentItem(pageIndex);
}
Do not forget to create your customTab.xml.
Best regards.

In Fragment A's onClick() method, try this :
TabActivity tabs = (TabActivity) getParent();
tabs.getTabHost().setCurrentTab(2);

Options menu showing at different fragments(mostly in neighbour Fragment)

My view pager's Adapter is like:
public Pager(FragmentManager fm, int tabCount) {
super(fm);
this.tabCount = tabCount;
}
#Override
public Fragment getItem(int position) {
switch (position) {
case 0:
return new frag1();
case 1:
return new frag2();
case 2:
return new frag1();
case 3:
return new frag2();
case 4:
return new frag1();
default:
return null;
}
}
#Override
public int getCount() {
return tabCount;
}
}
how i set the tablayout and viewpager in java class:
for (int i = 0; i < 5; i++) {
tabLayout.addTab(tabLayout.newTab());
}
Pager adapter = new Pager(getSupportFragmentManager(), tabLayout.getTabCount());
viewPager.setAdapter(adapter);
viewPager.beginFakeDrag();
viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
I am getting weird error look like this:
W/FragmentManager: moveToState: Fragment state for frag2{2428405 #1 id=0x7f0c006a} not updated inline; expected state 3 found 2
so how can i fix this issue?
I am getting answers from stack but it doesn't solve my issue,
so anyone have any knowledge about this, kindly help me!

Replace this line viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout)); with tabLayout.setTabsFromPagerAdapter(adapter);

Try connecting the tabLayout with the viewPager with tabLayout.setupWithViewPager(viewPager) instead of adding the tabs manually in the loop.

available_bus_fragment.xml
<android.support.design.widget.TabLayout
android:id="#+id/tabs"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:tabGravity="fill"
android:background="#d4d4d4"
app:tabMode="fixed" />
<android.support.v4.view.ViewPager
android:id="#+id/viewpager"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#e8e8e8"
app:layout_behavior="#string/appbar_scrolling_view_behavior" />
ViewPagerAdapter.java is adapter for ViewPager.
public class ViewPagerAdapter extends FragmentStatePagerAdapter {
public ViewPagerAdapter(FragmentManager manager) {
super(manager);
}
#Override
public int getItemPosition(Object object) {
return POSITION_NONE;
}
#Override
public int getCount() {
return 3;
}
#Override
public CharSequence getPageTitle(int position) {
return String.valueOf(position);
}
#Override
public Fragment getItem(int position) {
switch (position) {
case 0:
Fragment tab1 = new YourFragment1();
return tab1;
case 1:
Fragment tab2 = new YourFragment1();
return tab2;
case 2:
Fragment tab3 = new YourFragment1();
return tab3;
}
return null;
}}
This is your class where you set adapter of Viewpager.
public class MyFragment extends Fragment {
View rootView;
ViewPagerAdapter adapter;
TabLayout tabLayout;
ViewPager viewPager;
private int[] tabIcons = {
R.drawable.tabclock,
R.drawable.clock,
R.drawable.tab_rupee
};
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
rootView = getLayoutInflater(savedInstanceState).inflate(R.layout.available_bus_fragment, null);
tabLayout = (TabLayout) rootView.findViewById(R.id.tabs);
viewPager = (ViewPager) rootView.findViewById(R.id.viewpager);
adapter = new ViewPagerAdapter(getChildFragmentManager());
viewPager.setAdapter(adapter);
tabLayout.setupWithViewPager(viewPager);
tabLayout.setTabsFromPagerAdapter(adapter);
setupTabIcons();
return rootView;
}
private void setupTabIcons() {
tabLayout.getTabAt(0).setIcon(tabIcons[0]).setTag("Departure").setText("Departure");
tabLayout.getTabAt(1).setIcon(tabIcons[1]).setTag("Duration").setText("Duration");
tabLayout.getTabAt(2).setIcon(tabIcons[2]).setTag("Price").setText("Price");
} }

Fragment becomes blank after asking for runtime permission

I am working on viewPager with fragment and it was working all things perfect before I have start implementing runtime permission for different module.
Here is my viewPager Adapter.
public class DashboardAdapter extends FragmentStatePagerAdapter {
public DashboardAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int position) {
switch (position) {
case 0:
return FunkyInboxFragment.newInstance(position);
case 1:
return FunkyTakePhotoFragment.newInstance(position);
case 2:
return FunkyAddFriendsFragmnet.newInstance(position);
default:
return FunkyTakePhotoFragment.newInstance(position);
}
}
#Override
public int getCount() {
return 3;
}
#Override
public Object instantiateItem(ViewGroup container, int position) {
Fragment fragment = (Fragment) super.instantiateItem(container, position);
return fragment;
}
#Override
public void destroyItem(ViewGroup container, int position, Object object) {
}
}
Here different fragments required different permissions so I have made a common activity class for it. It's working in the same fragment but after asking for a permission when I swipe the viewPager the fragment after next fragment and a fragment before previous fragment get blank. i have made all possible change in adapter but did not get a proper outcome.
Please can anyone help with it!

#Override
public int getCount() {
return 2;
}
//try this may be it work

package com.example.madhavgor.actionbardemolast;
import android.os.Bundle;
import android.support.design.widget.TabLayout;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends AppCompatActivity {
private Toolbar toolbar;
private TabLayout tabLayout;
private ViewPager viewPager;
private int[] tabIcons = {
R.mipmap.ic_launcher,R.mipmap.ic_launcher_bluetooth
};
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//toolbar = (Toolbar) findViewById(R.id.toolbar);
//setSupportActionBar(toolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
viewPager = (ViewPager) findViewById(R.id.viewPager);
setupViewPager(viewPager);
tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setupWithViewPager(viewPager);
setupTabIcons();
}
private void setupTabIcons() {
tabLayout.getTabAt(0).setIcon(tabIcons[0]);
tabLayout.getTabAt(1).setIcon(tabIcons[1]);
}
private void setupViewPager(ViewPager viewPager) {
ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager());
adapter.addFragment(new OneFragment(), "ONE");
adapter.addFragment(new SecondFragment(), "BLUETOOTH");
adapter.addFragment(new ThirdFragment(), "THREE");
viewPager.setAdapter(adapter);
}
class ViewPagerAdapter extends FragmentPagerAdapter {
private final List<Fragment> mFragmentList = new ArrayList<>();
private final List<String> mFragmentTitleList = new ArrayList<>();
public ViewPagerAdapter(FragmentManager manager) {
super(manager);
}
#Override
public Fragment getItem(int position) {
return mFragmentList.get(position);
}
#Override
public int getCount() {
return mFragmentList.size();
}
public void addFragment(Fragment fragment, String title) {
mFragmentList.add(fragment);
mFragmentTitleList.add(title);
}
#Override
public CharSequence getPageTitle(int position) {
return mFragmentTitleList.get(position);
}
}
}
//refer this code ....may be it will help you..

Tabs with fragment in activity

I have 2 tabs and 2 fragments.I did all for this guide
http://www.truiton.com/2015/06/android-tabs-example-fragments-viewpager/
but now I see tabs but dont see my fragments.What is the problem?
ViewPagerAdapter:
public class ViewPagerAdapter extends FragmentStatePagerAdapter {
int mNumOfTabs;
public ViewPagerAdapter(FragmentManager fm, int NumOfTabs) {
super(fm);
this.mNumOfTabs = NumOfTabs;
}
#Override
public android.support.v4.app.Fragment getItem(int position) {
switch (position) {
case 0:
Direct tab1 = new Direct();
return tab1;
case 1:
AdventuresFragment tab2 = new AdventuresFragment();
return tab2;
default:
return null;
}
}
#Override
public int getCount() {
return mNumOfTabs;
}
}
Activity with using this adapter:
public class TabsActivity extends Activity {
Fragment directFragmentTab = new Direct();
Fragment adventuresFragmentTab = new AdventuresFragment();
#TargetApi(Build.VERSION_CODES.LOLLIPOP)
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.tabs_activity);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
}
TabLayout tabLayout = (TabLayout) findViewById(R.id.tab_layout);
tabLayout.addTab(tabLayout.newTab().setText("Tab 1"));
tabLayout.addTab(tabLayout.newTab().setText("Tab 2"));
tabLayout.setTabGravity(TabLayout.GRAVITY_FILL);
final ViewPager viewPager = (ViewPager) findViewById(R.id.pager);
final PagerAdapter adapter = new PagerAdapter
() {
#Override
public int getCount() {
return 0;
}
#Override
public boolean isViewFromObject(View view, Object object) {
return false;
}
};
viewPager.setAdapter(adapter);
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) {
}
});
}
}

In your activity you are using the PagerAdapter class while your fragment handling class is named ViewPagerAdapter. You want to use the ViewPagerAdapter class instead.