-import android.support.design.widget.TabLayout;
-import android.support.v4.app.Fragment;
-import android.support.v4.app.FragmentManager;
-import android.support.v4.app.FragmentPagerAdapter;
-import android.support.v4.view.ViewPager;
-import android.support.v7.app.ActionBar;
-import android.support.v7.app.AppCompatActivity;
-import android.support.v7.widget.Toolbar;
+import android.preference.PreferenceManager;
+import android.view.WindowManager;
+
+import androidx.appcompat.app.ActionBar;
+import androidx.appcompat.app.AppCompatActivity;
+import androidx.appcompat.widget.Toolbar; // The AndroidX toolbar must be used until the minimum API is >= 21.
+import androidx.fragment.app.Fragment;
+import androidx.fragment.app.FragmentManager;
+import androidx.fragment.app.FragmentPagerAdapter;
+import androidx.viewpager.widget.ViewPager;
+
+import com.google.android.material.tabs.TabLayout;