I'm using Unity and the built in Oculus runtime (I haven't installed the full SDK from the Asset Store, as I haven't explicitly needed it yet) and have come across an issue while using Unity's UI system.
When I place any UI elements onto the canvas they show up in the editor's play mode (and any PC exported versions of the project, and any non-VR Android exports), but disappear as soon as I export for Gear VR. They do appear when I change the canvas' render mode to 'World Space', but that means that the canvas clips across different game objects in my world -- not exactly what I want.
You can have your canvases in world space, but on a layer above the other objects, so they will always be drawn on top. Make sure the camera which needs to render them is set to render the UI layer you set the canvases on. Depending on your setup, you may even wish to set up a separate camera specifically for rendering UI.
