MainActivity

package com.harunalrosyid.submission.activities;

import android.os.Bundle;
import android.view.MenuItem;

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

import com.google.android.material.bottomnavigation.BottomNavigationView;
import com.harunalrosyid.submission.R;
import com.harunalrosyid.submission.fragments.MovieFragment;
import com.harunalrosyid.submission.fragments.TvShowFragment;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {

    private BottomNavigationView.OnNavigationItemSelectedListener mOnNavigationItemSelectedListener
            = new BottomNavigationView.OnNavigationItemSelectedListener ( ) {

        @Override
        public boolean onNavigationItemSelected(@NonNull MenuItem item) {
            Fragment fragment;

            switch (item.getItemId ( )) {
                case R.id.navigation_movie:
                    fragment = new MovieFragment ();
                    getSupportFragmentManager().beginTransaction()
                            .replace(R.id.container_layout, fragment, fragment.getClass().getSimpleName())
                            .commit();
                    return true;
                case R.id.navigation_tv_show:
                    fragment = new TvShowFragment ();
                    getSupportFragmentManager().beginTransaction()
                            .replace(R.id.container_layout, fragment, fragment.getClass().getSimpleName())
                            .commit();
            }
            return false;
        }
    };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate ( savedInstanceState );
        setContentView ( R.layout.activity_main );
        BottomNavigationView navView = findViewById ( R.id.nav_view );
        navView.setOnNavigationItemSelectedListener ( mOnNavigationItemSelectedListener );

        if (savedInstanceState == null){
            navView.setSelectedItemId(R.id.navigation_movie);
        }

    }
    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);
        }
    }
}