音頻播放流管理

讀取或監(jiān)聽(tīng)?wèi)?yīng)用內(nèi)音頻流狀態(tài)變化

參考使用AudioRenderer開(kāi)發(fā)音頻播放功能或audio.createAudioRenderer，完成AudioRenderer的創(chuàng)建，然后可以通過(guò)以下兩種方式查看音頻流狀態(tài)的變化：

• 方法1：直接查看AudioRenderer的state：

  let audioRendererState = audioRenderer.state;
  console.info(`Current state is: ${audioRendererState }`)

• 方法2：注冊(cè)stateChange監(jiān)聽(tīng)AudioRenderer的狀態(tài)變化：

  audioRenderer.on('stateChange', (rendererState) => {
    console.info(`State change to: ${rendererState}`)
  });

獲取state后可對(duì)照AudioState來(lái)進(jìn)行相應(yīng)的操作，比如更改暫停播放按鈕的顯示等。

讀取或監(jiān)聽(tīng)所有音頻流的變化

如果部分應(yīng)用需要查詢獲取所有音頻流的變化信息，可以通過(guò)AudioStreamManager讀取或監(jiān)聽(tīng)所有音頻流的變化。

如下為音頻流管理調(diào)用關(guān)系圖：

在進(jìn)行應(yīng)用開(kāi)發(fā)的過(guò)程中，開(kāi)發(fā)者需要使用getStreamManager()創(chuàng)建一個(gè)AudioStreamManager實(shí)例，進(jìn)而通過(guò)該實(shí)例管理音頻流。開(kāi)發(fā)者可通過(guò)調(diào)用on('audioRendererChange')監(jiān)聽(tīng)音頻流的變化，在音頻流狀態(tài)變化、設(shè)備變化時(shí)獲得通知。同時(shí)可通過(guò)off('audioRendererChange')取消相關(guān)事件的監(jiān)聽(tīng)。另外，開(kāi)發(fā)者可以主動(dòng)調(diào)用getCurrentAudioRendererInfoArray()來(lái)查詢播放流的唯一ID、播放流客戶端的UID、音頻流狀態(tài)等信息。

詳細(xì)API含義可參考音頻管理API文檔AudioStreamManager。

開(kāi)發(fā)步驟及注意事項(xiàng)

1. 創(chuàng)建AudioStreamManager實(shí)例。

   在使用AudioStreamManager的API前，需要使用getStreamManager()創(chuàng)建一個(gè)AudioStreamManager實(shí)例。

   import audio from '@ohos.multimedia.audio';
   let audioManager = audio.getAudioManager();
   let audioStreamManager = audioManager.getStreamManager();

2. 使用on('audioRendererChange')監(jiān)聽(tīng)音頻播放流的變化。 如果音頻流監(jiān)聽(tīng)?wèi)?yīng)用需要在音頻播放流狀態(tài)變化、設(shè)備變化時(shí)獲取通知，可以訂閱該事件。

   audioStreamManager.on('audioRendererChange',  (AudioRendererChangeInfoArray) => {
     for (let i = 0; i < AudioRendererChangeInfoArray.length; i++) {
       let AudioRendererChangeInfo = AudioRendererChangeInfoArray[i];
       console.info(`## RendererChange on is called for ${i} ##`);
       console.info(`StreamId for ${i} is: ${AudioRendererChangeInfo.streamId}`);
       console.info(`Content ${i} is: ${AudioRendererChangeInfo.rendererInfo.content}`);
       console.info(`Stream ${i} is: ${AudioRendererChangeInfo.rendererInfo.usage}`);
       console.info(`Flag ${i} is: ${AudioRendererChangeInfo.rendererInfo.rendererFlags}`); 
       for (let j = 0;j < AudioRendererChangeInfo.deviceDescriptors.length; j++) {
         console.info(`Id: ${i} : ${AudioRendererChangeInfo.deviceDescriptors[j].id}`);
         console.info(`Type: ${i} : ${AudioRendererChangeInfo.deviceDescriptors[j].deviceType}`);
         console.info(`Role: ${i} : ${AudioRendererChangeInfo.deviceDescriptors[j].deviceRole}`);
         console.info(`Name: ${i} : ${AudioRendererChangeInfo.deviceDescriptors[j].name}`);
         console.info(`Address: ${i} : ${AudioRendererChangeInfo.deviceDescriptors[j].address}`);
         console.info(`SampleRates: ${i} : ${AudioRendererChangeInfo.deviceDescriptors[j].sampleRates[0]}`);
         console.info(`ChannelCount ${i} : ${AudioRendererChangeInfo.deviceDescriptors[j].channelCounts[0]}`);
         console.info(`ChannelMask: ${i} : ${AudioRendererChangeInfo.deviceDescriptors[j].channelMasks}`);
       }
     }
   });

3. （可選）使用off('audioRendererChange')取消監(jiān)聽(tīng)音頻播放流變化。

   audioStreamManager.off('audioRendererChange');
   console.info('RendererChange Off is called ');

4. （可選）使用getCurrentAudioRendererInfoArray()獲取所有音頻播放流的信息。
   該接口可獲取音頻播放流唯一ID，音頻播放客戶端的UID，音頻狀態(tài)以及音頻播放器的其他信息。

   說(shuō)明

   對(duì)所有音頻流狀態(tài)進(jìn)行監(jiān)聽(tīng)的應(yīng)用需要申請(qǐng)權(quán)限ohos.permission.USE_BLUETOOTH，否則無(wú)法獲得實(shí)際的設(shè)備名稱和設(shè)備地址信息，查詢到的設(shè)備名稱和設(shè)備地址（藍(lán)牙設(shè)備的相關(guān)屬性）將為空字符串。

   async function getCurrentAudioRendererInfoArray(){
     await audioStreamManager.getCurrentAudioRendererInfoArray().then( function (AudioRendererChangeInfoArray) {
       console.info(`getCurrentAudioRendererInfoArray  Get Promise is called `);
       if (AudioRendererChangeInfoArray != null) {s
         for (let i = 0; i < AudioRendererChangeInfoArray.length; i++) {
           let AudioRendererChangeInfo = AudioRendererChangeInfoArray[i];
           console.info(`StreamId for ${i} is: ${AudioRendererChangeInfo.streamId}`);
           console.info(`Content ${i} is: ${AudioRendererChangeInfo.rendererInfo.content}`);
           console.info(`Stream ${i} is: ${AudioRendererChangeInfo.rendererInfo.usage}`);
           console.info(`Flag ${i} is: ${AudioRendererChangeInfo.rendererInfo.rendererFlags}`);  
           for (let j = 0;j < AudioRendererChangeInfo.deviceDescriptors.length; j++) {
             console.info(`Id: ${i} : ${AudioRendererChangeInfo.deviceDescriptors[j].id}`);
             console.info(`Type: ${i} : ${AudioRendererChangeInfo.deviceDescriptors[j].deviceType}`);
             console.info(`Role: ${i} : ${AudioRendererChangeInfo.deviceDescriptors[j].deviceRole}`);
             console.info(`Name: ${i} : ${AudioRendererChangeInfo.deviceDescriptors[j].name}`);
             console.info(`Address: ${i} : ${AudioRendererChangeInfo.deviceDescriptors[j].address}`);
             console.info(`SampleRates: ${i} : ${AudioRendererChangeInfo.deviceDescriptors[j].sampleRates[0]}`);
             console.info(`ChannelCount ${i} : ${AudioRendererChangeInfo.deviceDescriptors[j].channelCounts[0]}`);
             console.info(`ChannelMask: ${i} : ${AudioRendererChangeInfo.deviceDescriptors[j].channelMasks}`);
           }
         }
       }
     }).catch((err) => {
       console.error(`Invoke getCurrentAudioRendererInfoArray failed, code is ${err.code}, message is ${err.message}`);
     });
   }