If your have iTunes music collection on your Mac or PC computer, or audio songs in iPhone/iPad/iPod device, you just need to use some app to listen to the same songs on your Nexus 7 or other android phone.
Apple allows user to AirPlay M4P, M4A, AAC music from iTunes or iOS devices to other Apple TV, AirPort Express devices in the room wirelessly. Without converting the iTunes music to Nexus 7 compatible format and transfer the output files, let's take a look at how to play iTunes music to Android Tablet/Phones via AirPlay.
Android HiFi is a an AirPlay server for audio playback in Google Play Store. It just turn your android device into a AirPlay receiver with audio, but doesn't support video playback. To stream audio, iTunes/iOS and Nexus 7 need to be on same WiFi connection.