After working on android and the qtmultimedia library for a week,
I have a much better understanding of what works and what doesn't.
The resulting design is thus presented. We will have one
CameraController class which refers to one overlay panel in QML
and in different places in the GUI objects based on QRScanner
can be created to initiate a scan.
This additionally moves the actual scanning out of the GUI thread
since blocking that is a no-no.
Now to move towards actually supporting scanning usecases.
This takes the camera feed and pipes it through the ZXing (pronounced
zebra-crossing) library which detects the barcodes in the image.
When we find it, we pluck out the text.
This makes it possible for the mobile app on Android to use the camera.
We only ask for permission when the user actively goes to the 'QR-Scan'
tab, and we show a simple preview of the camera feed.
Notice that the permissions stuff is quite ugly right now due to Qt
having that module in development and the public APIs are simply not
available yet. But at least it works, which is all that matters.
When the next minor Qt release comes out we can hopefully clean this
up and use a version that needs no ifdefs.
tomFlowee