Tablayout in Android using java

Tablayout

MainActivity.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:orientation="vertical"
    tools:context=".TabBar_Activity">

    <com.google.android.material.tabs.TabLayout
        android:id="@+id/tab_layout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

    <androidx.viewpager.widget.ViewPager
        android:layout_width="match_parent"
        android:id="@+id/view_pager_tab"
        android:layout_height="match_parent" />

</LinearLayout>

MainActivity.xml

package com.example.myapplication06;

import androidx.appcompat.app.AppCompatActivity;
import androidx.viewpager.widget.ViewPager;

import android.os.Bundle;
import android.view.View;

import com.example.myapplication06.Adapter.Fragment_view_pager_Adapter;
import com.google.android.material.tabs.TabLayout;

public class TabBar_Activity extends AppCompatActivity {

    private TabLayout tab_layout;
    private ViewPager view_pager_tab;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_tab_bar);
        tab_layout=findViewById(R.id.tab_layout);
        view_pager_tab=findViewById(R.id.view_pager_tab);

        tab_layout.addTab(tab_layout.newTab().setText("Home"));
        tab_layout.addTab(tab_layout.newTab().setText("Status"));
        tab_layout.addTab(tab_layout.newTab().setText("Call"));


        tab_layout.addOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
            @Override
            public void onTabSelected(TabLayout.Tab tab) {
                view_pager_tab.setCurrentItem(tab.getPosition());
            }

            @Override
            public void onTabUnselected(TabLayout.Tab tab) {

            }

            @Override
            public void onTabReselected(TabLayout.Tab tab) {

            }
        });

        //Adapter
        Fragment_view_pager_Adapter adapter=new Fragment_view_pager_Adapter(getSupportFragmentManager(),TabBar_Activity.this);
        view_pager_tab.setAdapter(adapter);

        view_pager_tab.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tab_layout));

    }
}

Adapter.java

package com.example.myapplication06.Adapter;

import android.app.Activity;

import androidx.annotation.NonNull;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentPagerAdapter;

import com.example.myapplication06.Fragment.OneFragment;
import com.example.myapplication06.Fragment.SecondFragment;
import com.example.myapplication06.TabBar_Activity;

public class Fragment_view_pager_Adapter extends FragmentPagerAdapter {

    Activity activity;

    public Fragment_view_pager_Adapter(@NonNull FragmentManager fm, TabBar_Activity tabBar_activity) {
        super(fm);
        activity = tabBar_activity;
    }

    @NonNull
    @Override
    public Fragment getItem(int position) {
        switch (position) {
            case 0:
                OneFragment oneFragment=new OneFragment();
                return  oneFragment;

            case 1:
                SecondFragment secondFragment=new SecondFragment();
                return secondFragment;

        }
        return null;
    }

    @Override
    public int getCount() {
        return 2;
    }
}