With U3DXT library, can I check if the device’s wifi is enabled? What about Bluetooth?
It’s possible to show a system-dialog regarding Bluetooth, can I do this through your API?
here’s an example of how to show the dialog box (even though the question is about doing the opposite)
No, not really. Unity doesn’t have a built in Plugin for that but you can easily make your own. Assuming you are making this for Android devices, you need to create a function that shows the dialog in Java then compile it to dll file. For iOS, you need to write a simple function that shows the dialog using objectie-C then compile it to dll.
This DLL Functions can then be called from unity.