# 通知

/// 被打断通知
extern NSNotificationName const AVAudioSessionInterruptionNotification API_AVAILABLE(ios(6.0), watchos(2.0), tvos(9.0)) API_UNAVAILABLE(macos);

/// 路线改变通知(如,扬声器切换为耳机.也就是耳机插入设备)
extern NSNotificationName const AVAudioSessionRouteChangeNotification API_AVAILABLE(ios(6.0), watchos(2.0), tvos(9.0)) API_UNAVAILABLE(macos);

/// 当媒体服务丢失的时候的通知.
extern NSNotificationName const AVAudioSessionMediaServicesWereLostNotification API_AVAILABLE(ios(7.0), watchos(2.0), tvos(9.0)) API_UNAVAILABLE(macos);

/// 媒体服务重启时的通知
extern NSNotificationName const AVAudioSessionMediaServicesWereResetNotification API_AVAILABLE(ios(6.0), watchos(2.0), tvos(9.0)) API_UNAVAILABLE(macos);

/// 其他App占用/解除占用AVAudioSession通知
extern NSNotificationName const AVAudioSessionSilenceSecondaryAudioHintNotification API_AVAILABLE(ios(8.0), watchos(2.0), tvos(9.0)) API_UNAVAILABLE(macos);

# 通知中userInfo对应的key

/// `AVAudioSessionInterruptionNotification`的键,表示被中断的类型(AVAudioSessionInterruptionType)
extern NSString *const AVAudioSessionInterruptionTypeKey API_AVAILABLE(ios(6.0), watchos(2.0), tvos(9.0)) API_UNAVAILABLE(macos);

/// 仅用于中断事件中,类型为`AVAudioSessionInterruptionOptions `
extern NSString *const AVAudioSessionInterruptionOptionKey API_AVAILABLE(ios(6.0), watchos(2.0), tvos(9.0)) API_UNAVAILABLE(macos);

/// 仅仅在打断事件中,值为BOOL类型.ture表示是系统暂停的,false表示是其他的音频会话终端的.
extern NSString *const AVAudioSessionInterruptionWasSuspendedKey API_AVAILABLE(ios(10.3), watchos(2.3), tvos(10.3)) API_UNAVAILABLE(macos);

/// 用于`AVAudioSessionRouteChangeNotification`.值的类型是NSNumber.
extern NSString *const AVAudioSessionRouteChangeReasonKey API_AVAILABLE(ios(6.0), watchos(2.0), tvos(9.0)) API_UNAVAILABLE(macos);

/// 值是`AVAudioSessionRouteDescription`
extern NSString *const AVAudioSessionRouteChangePreviousRouteKey API_AVAILABLE(ios(6.0), watchos(2.0), tvos(9.0)) API_UNAVAILABLE(macos);

/// 用于`AVAudioSessionSilenceSecondaryAudioHintNotification`.值的类型是NSNumber.
extern NSString *const AVAudioSessionSilenceSecondaryAudioHintTypeKey API_AVAILABLE(ios(8.0), watchos(2.0), tvos(9.0)) API_UNAVAILABLE(macos);

AVAudioSessionInterruptionNotification (音频被中断通知)

/// MARK: 用到的枚举
typedef NS_ENUM(NSUInteger, AVAudioSessionInterruptionType)
{
	AVAudioSessionInterruptionTypeBegan = 1,  /* the system has interrupted your audio session */
	AVAudioSessionInterruptionTypeEnded = 0,  /* the interruption has ended */
};

/// MARK: 使用方式

/// 添加通知
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(audioSessionInterruptionNotification:) name:AVAudioSessionInterruptionNotification object:nil];

- (void)audioSessionInterruptionNotification:(NSNotification *)noti {
    NSInteger InterruptionType = [[noti.userInfo objectForKey:AVAudioSessionInterruptionTypeKey] integerValue];
    switch (InterruptionType) {
        case AVAudioSessionInterruptionTypeBegan: {
            NSLog(@"开始打断");
        }
            break;
        case AVAudioSessionInterruptionTypeEnded: {
            NSLog(@"结束打断");
        }
            break;
        default:
            break;
    }

}

当我们的App正在播放音频,然后我们开启了其他App播放音乐或者是突然来电话了,那么我们就会收到一个AVAudioSessionInterruptionNotification通知,然后当我们应用重新进入前台.也就是active状态的时候.我们会收到一个AVAudioSessionInterruptionTypeEnded.告诉我们打断已经结束.可以重新让我们的播放器继续播放了.(一定要重新进入前台).

noti.userInfo @{@"AVAudioSessionRouteChangePreviousRouteKey" :<id AVAudioSessionRouteDescription> ,@"AVAudioSessionRouteChangeReasonKey" :@()}

/// 其中AVAudioSessionRouteChangePreviousRouteKey

AVAudioSessionRouteChangeNotification (播放线路改变通知)

当抽插耳机等造成播放线路改变时会发送的通知

userInfo信息:

- (void)audioSessionRouteChangeNotification:(NSNotification *)noti {
    AVAudioSessionRouteDescription *routeDescription = [noti.userInfo valueForKey:AVAudioSessionRouteChangePreviousRouteKey];
    NSInteger reason = [[noti.userInfo valueForKey:AVAudioSessionRouteChangeReasonKey] integerValue];

}

typedef NS_ENUM(NSUInteger, AVAudioSessionRouteChangeReason)
{
	/// 未知原因
	AVAudioSessionRouteChangeReasonUnknown = 0,
	/// 有新设备可用
	AVAudioSessionRouteChangeReasonNewDeviceAvailable = 1,
	/// 老设备不可用
	AVAudioSessionRouteChangeReasonOldDeviceUnavailable = 2,
	/// 类别改变
	AVAudioSessionRouteChangeReasonCategoryChange = 3,
	/// App重置了输出设置
	AVAudioSessionRouteChangeReasonOverride = 4,
	/// 从睡眠状态唤醒
	AVAudioSessionRouteChangeReasonWakeFromSleep = 6,
	/// 当前category下没合适设备
	AVAudioSessionRouteChangeReasonNoSuitableRouteForCategory = 7,
	/// Rotuer的配置改变了
	AVAudioSessionRouteChangeReasonRouteConfigurationChange = 8 // added in iOS 7
};

AVAudioSessionMediaServicesWereLostNotification (媒体服务丢失通知)

详情

使用系统内置Developer功能的时候,会过一会儿才收到通知.此通知无userInfo.我们需要做的就是收到通知后看情况是否重启媒体服务.

AVAudioSessionMediaServicesWereResetNotification (媒体服务重启通知)

详情见上面的AVAudioSessionMediaServicesWereLostNotification详情.

AVAudioSessionSilenceSecondaryAudioHintNotification

其他设备占用了AVAudioSession通过userInfo中的AVAudioSessionSilenceSecondaryAudioHintTypeKey获取到的值有以下两种可能(类似上面的音频播放被中断)

AVAudioSessionSilenceSecondaryAudioHintTypeBegin 其他App开始占据Session
AVAudioSessionSilenceSecondaryAudioHintTypeEnd 其他App停止占用Session