The OpenROV project uses Android for it’s Trident Controller. If i recall correctly, this was prior to ROS2, the development team had been using DDS to exchange ROV telemetry and teleop control over the two wire tether to the surface level WiFi base station that PCs or the tablet proxy through to connect to the underwater robot. I recall they had to do a bit of hacking to get the optimal QoS working for streaming encoded video for low latency feedback with the android device’s network stack, given the Android’s Linux kernel lags quite a bit behind mainline, and that some may not even have multicast enabled.
https://store.sofarocean.com/products/trident-android-controller
Here was some of the old promo and slides that relates to talk OpenROV gave during Connext Conference 2017. Perhaps @spiderkeys who spoke then would know more?
https://info.rti.com/hubfs/US%20Connext%20Conference%202017%20Presentations/Open%20ROV%20Presentation%20.pdf
(see slide around p33 and p44)
I’m sure there are many more ground, aerial, service, and industrial robot based use cases for native mobile interfaces in integrating with ROS2 enabled applications. In particular it’d be nice to see something general, like an open source android app, either for viewing raw ROS2 messages, publishing smart phone sensor data, or something more substantial, equivalent to rviz2, so people would have a cookie cutter demo project to fork from for getting started on there own custom ROS2 apps. Mobile development is a bit of a bear to break into, and takes a lot of effort to stay afloat given how much of a moving target the ecosystem can be. Having a community maintained app/example to spring board from could help a lot of other ROS users.