Hi,
Good job. Well, perhaps there’s a bit of defensive code or sanity check in there. I suggest reporting that issue here: https://gitlab.kitware.com/groups/vtk/-/issues .
My two cents: if impl->Window is nullptr, then it’s likely there is a prior call that instantiates the object that impl->Window is supposed to point to. I don’t have experience in Android and Qt Quick, but I’d look at the part of the code where you setup your GUI and make Qt Quick and VTK start talking to each other. In normal Qt for desktop, we instantiate a QVTKOpenGLWindow before doing anything else related to rendering in VTK.
best,
PC