Chapter 2 Code Error

[imwangxuesen]

in chapter 2, we should set Session Category in '- (void)applicationWillResignActive:(UIApplication *)application',not '- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions' .
like this :

• (void)applicationWillResignActive:(UIApplication *)application {
  AVAudioSession *session=[AVAudioSession sharedInstance];
  [session setActive:YES error:nil];
  [session setCategory:AVAudioSessionCategoryPlayback error:nil];
  }

[imwangxuesen]

running on iOS 10.1.1