AVAudioSession 与 AVSpeechUtterance 混合

Question

我有一个问题，我想让 iPod 在后台播放音乐，在我的应用程序中我想让AVSpeechUtterance 降低 iPod 的音量，播放一串文本，然后我想让 iPod 继续播放。我已经尝试了几件事，但从来没有让 AVAudioSession 和 AVSpeechUtterance 一起工作得很好。我可以让 iPod 停止，暂停一会儿，然后重新开始播放。我可以看到我的字符串被传递给AVSpeechUtterance，但它不会优先于扬声器播放。这是我的代码：

视图已加载：

   - (void)viewDidLoad
   {
            //set the audio session for my app to play from the TTS library
            NSError *error;
            audioSession = [AVAudioSession sharedInstance];
            [audioSession setCategory:AVAudioSessionCategoryAmbient withOptions:1  error:&error];
            [audioSession setActive:YES error:&error];
            if(error){
                NSLog(@"Audio Error %@", error);
            }

            syn = [[AVSpeechSynthesizer alloc] init];
            syn.delegate = self;

            iPodMusicPlayer = [[MPMusicPlayerController alloc] init];

   }

这是我的语音功能：

   -(void)speech:(NSString *)string
   {
             if(audioSession.isOtherAudioPlaying){
                 wasPlaying = YES;
                 NSLog(@"Other audio is playing");
                 [iPodMusicPlayer pause];
             }

             AVSpeechUtterance *utterance = [AVSpeechUtterance speechUtteranceWithString:string];
             utterance.rate = 0.3f;
             utterance.volume = 1.0;
             [syn speakUtterance:utterance];

   }

AVSpeechSynthesizer演讲结束后调用的委托方法

   - (void)speechSynthesizer:(AVSpeechSynthesizer *)synthesizer didFinishSpeechUtterance:(AVSpeechUtterance *)utterance
   {
         if(wasPlaying){
            NSLog(@"Start Playing");
            [iPodMusicPlayer play];
            wasPlaying = NO;
         }
   }

我查看了AVAudioSessionhere 上的 Apple 文档，看起来我已经正确实施了一切。有谁知道我哪里出错了？

Answer 1

我只是想让大家知道，在进行了一些故障排除后，这就是我能够解决我的问题的方法。我不确定我是否喜欢这个解决方案，并且正在努力改进它。

查看已加载

    - (void)viewDidLoad
    {
            syn = [[AVSpeechSynthesizer alloc] init];
            syn.delegate = self;

            iPodMusicPlayer = [[MPMusicPlayerController alloc] init];
    }

语音功能

    -(void)speak:(NSString *)string
    {

            audioSession = [AVAudioSession sharedInstance];

            NSError *setCategoryError = nil;
            NSError *activationError = nil;
            BOOL success = [audioSession setCategory:AVAudioSessionCategoryPlayback
                withOptions:AVAudioSessionCategoryOptionMixWithOthers error:&setCategoryError];

            [audioSession setActive:YES error:&activationError];

            if(audioSession.isOtherAudioPlaying){
                wasPlaying = YES;
                NSLog(@"Other audio is playing");
                [iPodMusicPlayer pause];
            }

            NSLog(@"Success %hhd", success);

            AVSpeechUtterance *utterance = [AVSpeechUtterance           speechUtteranceWithString:string];
            utterance.rate = 0.3f;
            utterance.volume = 1.0;
            [syn speakUtterance:utterance];
     }

语音完成后调用的 AVSpeechSynthesizer 委托方法

     - (void)speechSynthesizer:(AVSpeechSynthesizer *)synthesizer didFinishSpeechUtterance:(AVSpeechUtterance *)utterance
     {
            if(wasPlaying){
                NSLog(@"Start Playing");
               [iPodMusicPlayer play];
               wasPlaying = NO;
            }
     }