These android apps from the Google playstore allow you to listen to Youtube music videos in the background of your Samsung, HTC or any android device. No more dealing with Youtube stopping when you open up another app. Some of these apps are alternatives to Youtube app and run by themselves without the Youtube app. They directly access Youtube. You can now finally muti-task with Youtube on your android device.
https://play.google.com/store/apps/details?id=com.jrzheng.supertubeplayer SuperTube is a free Youtube player supports background playback, floating window (popup) and repeat playlist.
Viral Floating Youtube Popup
https://play.google.com/store/apps/details?id=com.Mata.YTplayer Viral is an innovative video player that has many features which are missing from the standard YouTube app. For those of you who like to multi-task, it allows you to pop-out and float your videos above any other app, so you can watch a video and send text messages, emails or just browse the Internet. If your device is powerful enough, you can even view multiple floating videos! You can also choose to visualize your videos in fullscreen mode or minimize the playing video to the notification tray so you can listen to the audio in the background – great for listening music or podcasts from YouTube while you’re on the run!
uListen (YouTube Audio)
With uListen you can finally start “Listening” to YouTube videos on your Android Device. uListen is an unofficial YouTube player, that lets you stream audio out of YouTube videos allowing you to save precious bandwidth and reach faster buffering times.