I use the MPVolumeView to show a list of audio output device. And my iPhone is connected to a Bluetooth headset. Somehow the MPVolumeView doesn't show the headset. When i use the native Phone app, i can see the headset is listed.
The documentation of MPVolumeView doesn't give much information to debug this case.
The documentation of MPVolumeView doesn't give much information to debug this case.