Issue I am using MPVolumeView, get the linker Error, fails to compile. Undefined symbols for architecture i386:   "_OBJC_CLASS_$_MPVolumeView", referenced from:       objc-class-ref in AudioViewController.o ld: symbol(s) not found for architecture i386 clang: error: linker command failed with exit code 1 (use -v to see invocation) Which framework should be linked with the project?< Answer Add the MediaPlayer framework to your project and #import <MediaPlayer/MediaPlayer.h> where ever you are using the MPVolumeView.