Then I could easily parse the XML file using Qt and display it in a
neat way in the mobile app.
I’m not sure if this is the best approach, so am open to
recommendations.
Or you could just stick with HTML and go for PhoneGap, gives you just
about every mobile platform you could ever wish for.
For your data exchange, JSON is probably the best one. It’s much less
verbose than XML in just about any case. In any case, for mobile
devices (and even for a snappy desktop experience), you want to build
your app to transfer the least amount of data possible. Plenty of
resources about that around the web.