问题
I have implemented audio playback using AVPlayer, playing a remote mp3 url.
I want to display the information about the currently playing audio using the MPNowPlayingInfoCenter nowPlayingInfo method.
When I lock the screen, I do see the image and title I set, so I know that this method is registering the information in some way, but when I switch to AirPlay to an AppleTV, the display looks like a generic video output, with the progress bar at bottom, but elapsed time and duration correctly displayed.
If I set this same nowPlayingInfo, but then start some audio using an AudioQueue, then it properly displays the image on half the screen (it looks just like playing a podcast with the iPod/Music app).
Is this just a limitation of AirPlay support for audio using AVPlayer, or is there some way to get it to display the image and info properly?
回答1:
Ok - I dug through the apple dev forums and found a hint.
If you are using AVPlayer for audio only, and want it to work in the background while doing airplay, you need to disable the allowsAirPlayVideo setting.
Apparently AVPlayer on iOS 5+ assumes that it is playing back video via AirPlay, and so does not allow backgrounding, unless you explicitly disable video AirPlay.
Once you disable this (i.e. self.player.allowsAirPlayVideo = NO;) then your audio will still play via AirPlay, but now it will now show the audio/ipod like interface correctly.
回答2:
If you're on iOS7 you've got to disable external playback :
self.player.allowsExternalPlayback = NO;
来源：https://stackoverflow.com/questions/8808031/mpnowplayinginfocenter-nowplayinginfo-ignored-for-avplayer-audio-via-airplay