#鸿蒙通关秘籍#HarmonyOS NEXT后台长时任务如何申请与管理？

在HarmonyOS NEXT中，应用在后台执行长时间任务需要申请长时任务，以避免被系统挂起的情况。该操作需要如下步骤：

1. 必须申请ohos.permission.KEEP_BACKGROUND_RUNNING权限。可以在module.json5或config.json文件中声明所需的权限。
2. 在module.json5中，为需要使用长时任务的UIAbility上声明相应的长时任务类型，示例如下：

   "module": {
       "abilities": [
           {
               "backgroundModes": [
               "audioRecording"
               ], 
           }
       ],
       ...
   }
   

3. 通过Promise接口startBackgroundRunning和stopBackgroundRunning来申请和取消长时任务。以下是调用示例：

   startContinuousTask() {
     let wantAgentInfo = {
       wants: [
         {
           bundleName: "com.example.myapplication",
           abilityName: "com.example.myapplication.MainAbility"
         }
       ],
       actionType: wantAgent.OperationType.START_ABILITY,
       requestCode: 0,
       wantAgentFlags: [wantAgent.WantAgentFlags.UPDATE_PRESENT_FLAG]
     };
   
     wantAgent.getWantAgent(wantAgentInfo).then(wantAgentObj => {
        backgroundTaskManager.startBackgroundRunning(this.context,
          backgroundTaskManager.BackgroundMode.AUDIO_RECORDING, wantAgentObj).then(() => {
          console.info(`Succeeded in startBackgroundRunning.`);
        }).catch(err => {
          console.error(`Failed to startBackgroundRunning. Code is ${err.code}, message is ${err.message}`);
        });
     });
   }
   
   stopContinuousTask() {
      backgroundTaskManager.stopBackgroundRunning(this.context).then(() => {
        console.info(`Succeeded in stopBackgroundRunning.`);
      }).catch(err => {
        console.error(`Failed to stopBackgroundRunning. Code is ${err.code}, message is ${err.message}`);
      });
   }
   

通过这些步骤，确保在应用的后台任务中使用符合条件的长时任务类型，实现应用的长时间稳定运行。