[Larrikin]

Android development is Kotlin. Sometimes C++, but I've never seen or worked on a project that needed it. Using any other language will be an uphill battle that will make your life harder.

OpenCV also has a warning and a guide for people trying to use it for Android dev https://opencv.org/android/. Did you look through this?

Also why do you want to use a USB camera when every phone has a couple cameras built in? I think you're going down a road of frustration if you think mobile OSes aren't built with completely different use cases in mind than desktop environments.

Theres a lot of information the Android dev site about getting up and running with the camera. You can pass a lot of the photo stuff off to other camera apps on your phone, but if you really need to do stuff in the app theres an official Android library for making your life easier. Theres also a lot of official Android libraries and well known libraries for images and videos that might be easier to work with than OpenCV. You don't actually say what you are trying to ultimately do.

Gradle is the part of Android dev everyone hates.