Using front cam on android?

This sounds like a pretty simple question:

I just want to use the front camera on android to take a picture (Building an AR project). And it would be nice that people can choose to make a picture of themselfs with these models and share it. AR is working thanks to unreal4ar. But the front cam isn’t.

I tried this:

But openURL seems to fail. i printed the url / name from the front camera and these values are correct?