/.../src/android/java/src/org/qtproject/qt/android/bindings/QtActivityLoader.java:79: Warning: Accessing internal APIs via reflection is not supported and may not work on all devices or in the future [PrivateApi]
            m_activity.setTheme(Class.forName("android.R$style").getDeclaredField(QT_ANDROID_DEFAULT_THEME).getInt(null));
                                ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

   Explanation for issues of type "PrivateApi":
   Using reflection to access hidden/private Android APIs is not safe; it will
   often not work on devices from other vendors, and it may suddenly stop
   working (if the API is removed) or crash spectacularly (if the API behavior
   changes, since there are no guarantees for compatibility).

   https://developer.android.com/preview/restrictions-non-sdk-interfaces