Tab layout with Fragments

Question

I am trying to load different fragments on each tab with Android Tablayout and PagerAdapter. Tabs are working fine however corresponding fragment is not loading on my scree. Here is the code:

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;


public class Tab1 extends Fragment {

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        return inflater.inflate(R.layout.tab1, container, false);
    }
}

Created total 3 tab classes for each fragment XML. Here is my xml for Fragment:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:text="Tab 1"
        android:textAppearance="?android:attr/textAppearanceLarge"/>
</RelativeLayout>

My Activity class:

import android.app.ActionBar;
import android.content.Intent;
import android.support.design.widget.TabLayout;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.Toolbar;
import android.widget.Toast;

import java.util.logging.Logger;

public class DashboardActivity extends AppCompatActivity implements TabLayout.OnTabSelectedListener{

    //This is our tablayout
    private TabLayout tabLayout;

    //This is our viewPager
    private ViewPager viewPager;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_dashboard);

        //Adding toolbar to the activity
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        //Initializing the tablayout
        tabLayout = (TabLayout) findViewById(R.id.tabLayout);

        //Adding the tabs using addTab() method
        tabLayout.addTab(tabLayout.newTab().setText("Your Tab Title"));
        tabLayout.addTab(tabLayout.newTab().setText("Your Tab Title"));
        tabLayout.addTab(tabLayout.newTab().setText("Your Tab Title"));
        tabLayout.setTabGravity(TabLayout.GRAVITY_FILL);

        //Initializing viewPager
        viewPager = (ViewPager) findViewById(R.id.pager);

        //Creating our pager adapter
        Pager adapter = new Pager(getSupportFragmentManager(), tabLayout.getTabCount());

        //Adding adapter to pager
        viewPager.setAdapter(adapter);

        //Adding onTabSelectedListener to swipe views
        tabLayout.setOnTabSelectedListener(this);
    }

    @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) {

    }
}

My pager adapter class is :

public class Pager extends FragmentStatePagerAdapter {

    //integer to count number of tabs
    int tabCount;

    //Constructor to the class
    public Pager(FragmentManager fm, int tabCount) {
        super(fm);
        //Initializing tab count
        this.tabCount= tabCount;
    }

    //Overriding method getItem
    @Override
    public Fragment getItem(int position) {
        //Returning the current tabs
        switch (position) {
            case 0:
                Tab1 tab1 = new Tab1();
                return tab1;
            case 1:
                Tab2 tab2 = new Tab2();
                return tab2;
            case 2:
                Tab3 tab3 = new Tab3();
                return tab3;
            default:
                return null;
        }
    }

    //Overriden method getCount to get the number of tabs
    @Override
    public int getCount() {
        return tabCount;
    }
}

Activity Dashboard Layout file:

<android.support.design.widget.TabLayout
    android:id="@+id/tabLayout"
    android:layout_width="368dp"
    android:layout_height="wrap_content"
    app:tabMode="fixed"
    tools:layout_editor_absoluteX="8dp"
    app:layout_constraintTop_toTopOf="parent"
    android:layout_marginTop="8dp"
    android:onClick="loadOption"/>

<android.support.v4.view.ViewPager
    android:id="@+id/pager"
    android:layout_width="0dp"
    android:layout_height="0dp"
    android:layout_weight="1"
    android:background="@android:color/white"
    tools:layout_editor_absoluteY="0dp"
    tools:layout_editor_absoluteX="8dp"
    tools:ignore="MissingConstraints" />

Styles.xml file:

<resources>

    <!-- Base application theme. -->
    <style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
        <!-- Customize your theme here. -->
        <item name="colorPrimary">@color/colorPrimary</item>
        <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
        <item name="colorAccent">@color/colorAccent</item>
    </style>

    <style name="AppTheme.NoActionBar">
        <item name="windowActionBar">false</item>
        <item name="windowNoTitle">true</item>
    </style>

    <style name="AppTheme.AppBarOverlay" parent="ThemeOverlay.AppCompat.Dark.ActionBar" />

    <style name="AppTheme.PopupOverlay" parent="ThemeOverlay.AppCompat.Light" />

</resources>

Any suggestions.

Answer 1

If it is not there, put your main layout inside a LinearLayout or another ViewGroup. If you go for LinearLayout:

The layout_height of the viewpager is 0dp. Change it to match_parent as well as for the layout_width.

Remove the linear_layout weight="1"

You can also add android:layout_marginTop="?android:actionBarSize" for the view pager to be under the action bar.

Answer 2

try this,hope that it will help for you.

PagerAdapter class

public class HomeViewPagerAdapter extends FragmentPagerAdapter {
private List<Fragment> mFragmentList = new ArrayList<>();
private List<String> mTitleList = new ArrayList<>();

public HomeViewPagerAdapter(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);
    mTitleList.add(title);
}

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

}

MyActivity Class

HomeViewPagerAdapter homeViewPagerAdapter = new HomeViewPagerAdapter(getChildFragmentManager());

    // add whichever fragments you want to add
    homeViewPagerAdapter.addFragment(new Fragment(), "yourfragment");

    viewpager.setAdapter(homeViewPagerAdapter);
    viewpager.setOffscreenPageLimit(2);
    tabLayout.setupWithViewPager(viewpager);

Answer 3

You have done everything good but you miss one line which bind viewpager with tab layout or display tab,

tabLayout.setupWithViewPager(viewPager);

Try this may be help you.

Answer 4

You need to add the following line in the onCreate() method of your activity :

viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));

Answer 5

Use tabLayout.setupWithViewPager(viewPager)

    .............
    .....................

    //Adding adapter to pager
    viewPager.setAdapter(adapter);

    tabLayout.setupWithViewPager(viewPager)

    //Adding onTabSelectedListener to swipe views
    tabLayout.setOnTabSelectedListener(this);

    ...........
    ....................

Answer 6

add this line and you are good to go

viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(
            tabLayout));