About the camera I think you best hope is use NDK (c++ bindings to android functions).
But you are out of luck as most of the links I search do not provide a solution.
The best answer I find is this :
Not tested, but I did a quick search because I will need this on the future.
Maybe to make it work without hacks you can make you app a android/iOS native application and call the go code as a SDK app. This way you can have all the calls on java/swift/objective-c.