TabLayout tabs text not displaying

The problem is you’re calling setupWithViewPager() after setting up your tabs with the addTab() calls, effectively overwriting them.

From the documentation of TabLayout regarding setupWithViewPager():

The tabs displayed in this
layout will be populated from the ViewPager adapter’s page titles.

If you would like to use your TabLayout with a ViewPager, you should override getPageTitle() in your PagerAdapter (and remove the addTab() calls, they are redundant).

For example:

public class ExamplePagerAdapter extends FragmentStatePagerAdapter {

    // tab titles
    private String[] tabTitles = new String[]{"Tab1", "Tab2", "Tab3"};

    public ExamplePagerAdapter(FragmentManager fm) {
        super(fm);
    }

    // overriding getPageTitle()
    @Override
    public CharSequence getPageTitle(int position) {
        return tabTitles[position];
    }

    @Override
    public Fragment getItem(int position) {
        switch (position) {
            case 0:
                return new Tab1Fragment();
            case 1:
                return new Tab2Fragment();
            case 2:
                return new Tab3Fragment();
            default:
                throw new RuntimeException("Invalid tab position");
        }
    }

    @Override
    public int getCount() {
        return tabTitles.length;
    }

    // ...
}