API Call into main activity and I wanna transfer data into fragments?

The following code is working fine but I want to transfer data on another fragment.
If someone has a clear and easy way, please let me know!
Many thanks for considering my request.

public class MainActivity extends AppCompatActivity implements NavigationView.OnNavigationItemSelectedListener
,WallpaperStarter.WallpaperListener{

TabLayout tabLayout;
ViewPager viewPager;
TabItem tabCategory, tabHome, tabPremium;
String fragmentPosition = "1";

WallpaperStarter wallpaperStarter;

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

    wallpaperStarter = new WallpaperStarter(this, AppConstants.webPrefix);
    wallpaperStarter.setStart(AppConstants.rootMetaLink);

    setupDrawerLayout();
    Utility.setStatusBarAndNavigationBarColorBlack(MainActivity.this);

    tabLayout = (TabLayout) findViewById(R.id.tabLayout);
    tabLayout.setHorizontalScrollBarEnabled(true);

    viewPager = (ViewPager) findViewById(R.id.viewPager);

    for (String string : AppConstant.MY_TABS) {
        tabLayout.addTab(tabLayout.newTab().setText(string));
    }


    PageAdapter pageAdapter = new PageAdapter(getSupportFragmentManager(), tabLayout.getTabCount());
    viewPager.setAdapter(pageAdapter);
    viewPager.setCurrentItem(0);
    viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
}


private void setupDrawerLayout() {

    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbarMain);
    setSupportActionBar(toolbar);

    DrawerLayout drawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);

    ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(this, drawerLayout, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);

    drawerLayout.addDrawerListener(toggle);
    toggle.syncState();

    NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);

    navigationView.setNavigationItemSelectedListener(this);

}


@Override
public boolean onNavigationItemSelected(@NonNull MenuItem item) {
    int id = item.getItemId();

    if (id == R.id.nav_home) {
        Utility.toast(MainActivity.this, "Home activity is clicked");
    } else if (id == R.id.downloads) {
        Utility.toast(MainActivity.this, "Download activity is clicked");

    } else if (id == R.id.edit) {
        Utility.toast(MainActivity.this, "Edit is clicked");

    } else if (id == R.id.more_app) {
        Utility.toast(MainActivity.this, "More App is clicked");
    }

    DrawerLayout drawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
    drawerLayout.closeDrawer(GravityCompat.START);
    return true;
}

@Override
public void onDataLoaded(ArrayList<String> nameList, ArrayList<String> countList) {

    int index = 2 ;

    ArrayList arrayList = wallpaperStarter.getSingleItems(nameList.get(index), countList.get(index));

    for(int cnt =0; cnt<countList.size(); cnt++){

        Log.e("data_item", "name:" + arrayList.get(cnt).toString());
        Log.e("data_item", "length:" + arrayList.get(cnt).toString());
    }
}