ios  如何判断设备处于静音模式

-(BOOL)silenced

{

     #if TARGET_IPHONE_SIMULATOR

         // return NO in simulator. Code causes crashes for some reason.

         return NO;

     #endif

 

    CFStringRef state;

    UInt32 propertySize = sizeof(CFStringRef);

    AudioSessionInitialize(NULL, NULL, NULL, NULL);

    AudioSessionGetProperty(kAudioSessionProperty_AudioRoute, &propertySize;, &state;);

    if(CFStringGetLength(state) > 0)

            return NO;

    else

            return YES;

}