Hello, I have same issue. I’ve opened BalloonPop demo app in QtCreator (installed by Felgoer installer). All components are up to date, so qt 5.4 is used. I’ve also got an error on QApplication not found so I added “QT += qml quick widgets” to the pro file (same as topic starter).
Felgo version 2.5 already uses Qt 5.5, could you please make sure that this version is installed (it is selected by default if you’re using the Felgo Installer) and try to configure your project with a 5.5 target?
I’ve rechecked my Felgo installation and found that Qt 5.5 was installed only for Android platform. I’ve installed it for desktop as well and switch project in QtCreator to qt 5.5 desktop kit. But there are no changes here. Most strange thing, that everything was working some time ago. May be before I’ve updated to Qt 5.5 for Android platform.