adroitandroid

<?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">

    <FrameLayout
        android:id="@+id/fragment_container"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
</RelativeLayout>

adroitandroid

abstract class BaseBottomNavActivity extends BaseActivity { // you can directly extend AppCompatActivity

    @Override
    @CallSuper
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        initOnCreate(savedInstanceState);
        getBottomNavigationBar().setOnTabSelectionListener(
                new CustomBottomNavigationBar.OnTabSelectionListener() {
                    @Override