2. AppCompatDialog: 4. Theme.AppCompat: <androidx.appcompat.widget.Toolbar android:id="@+id/my_toolbar" android:layout_width="match_parent" android:layout_height="?attr/actionBarSize" android:background="?attr/colorPrimary" android:elevation="4dp" android:theme="@style/ThemeOverlay.AppCompat.ActionBar" /> public class MainActivity extends AppCompatActivity { private Toolbar toolbar; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); toolbar = findViewById(R.id.my_toolbar); setSupportActionBar(toolbar); } }