harmony 鸿蒙延迟任务调度开发指导

2022-08-09
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延迟任务调度开发指导

场景介绍

应用要执行对实时性要求不高的任务或持久性任务的时候，比如设备空闲时候做一次数据学习等场景，可以使用延迟调度任务，该机制在满足应用设定条件的时候，会根据系统当前状态，如内存、功耗、温度等统一决策调度时间，WorkSchedulerExtensionAbility提供了延迟任务回调拓展能力，注册延迟任务后需要实现延迟任务回调拓展能力。延迟任务调度约束见延迟任务调度约束。

接口说明

表1 workScheduler主要接口

接口名	接口描述
startWork(work: WorkInfo): void;	延迟调度任务申请
stopWork(work: WorkInfo, needCancel?: boolean): void;	延迟调度任务取消
getWorkStatus(workId: number, callback: AsyncCallback<WorkInfo>): void;	获取延迟调度任务状态（Callback形式）
getWorkStatus(workId: number): Promise<WorkInfo>;	获取延迟调度任务状态（Promise形式）
obtainAllWorks(callback: AsyncCallback<void>): Array<WorkInfo>;	获取所有延迟调度任务（Callback形式）
obtainAllWorks(): Promise>;	获取所有延迟调度任务（Promise形式）
stopAndClearWorks(): void;	停止并清除任务
isLastWorkTimeOut(workId: number, callback: AsyncCallback<void>): boolean;	获取上次任务是否超时（针对RepeatWork，Callback形式）
isLastWorkTimeOut(workId: number): Promise<boolean>;	获取上次任务是否超时（针对RepeatWork，Promise形式）

表2 WorkInfo包含参数

WorkInfo设置参数约束见延迟任务调度约束

参数名	类型	描述
workId	number	延迟任务ID（必填）
bundleName	string	延迟任务Bundle名称（必填）
abilityName	string	延迟任务回调通知的组件名（必填）
networkType	NetworkType	网络类型
isCharging	boolean	是否充电
chargerType	ChargingType	充电类型
batteryLevel	number	电量
batteryStatus	BatteryStatus	电池状态
storageRequest	StorageRequest	存储状态
isRepeat	boolean	是否循环任务
repeatCycleTime	number	循环间隔
repeatCount	number	循环次数
parameters	{[key: string]: number	string

表3 延迟任务回调接口

接口名	接口描述
onWorkStart(work: WorkInfo): void	延迟调度任务开始回调
onWorkStop(work: WorkInfo): void	延迟调度任务结束回调

开发步骤

1、导入模块。

注册相关接口包导入：

import workScheduler from '@ohos.resourceschedule.workScheduler';

回调相关接口包导入：

import WorkSchedulerExtensionAbility from '@ohos.WorkSchedulerExtensionAbility';

2、开发对应的ExtensionAbility，用于回调执行具体的延迟任务。关于ExtensionAbility的介绍，参考ExtensionAbility机制和WorkSchedulerExtensionAbility开发指导。

import WorkSchedulerExtensionAbility from '@ohos.WorkSchedulerExtensionAbility';

export default class MyExtension extends WorkSchedulerExtensionAbility {
    onWorkStart(workInfo) {
        console.log('MyWorkSchedulerExtensionAbility onWorkStart' + JSON.stringify(workInfo));
    }
    onWorkStop(workInfo) {
        console.log('MyWorkSchedulerExtensionAbility onWorkStop' + JSON.stringify(workInfo));
    }
}

3、注册延迟任务

import workScheduler from '@ohos.resourceschedule.workScheduler';
    
let workInfo = {
    workId: 1,
    batteryStatus:workScheduler.BatteryStatus.BATTERY_STATUS_LOW,
    isRepeat: false,
    isPersisted: true,
    bundleName: "com.example.myapplication",
    abilityName: "MyExtension",
    parameters: {
      mykey0: 1,
      mykey1: "string value",
      mykey2: true,
      mykey3: 1.5
  }
}
try{
  workScheduler.startWork(workInfo);
  console.info('workschedulerLog startWork success');
} catch (error) {
  console.error(`workschedulerLog startwork failed. code is ${error.code} message is ${error.message}`);
}

4、取消延迟任务

import workScheduler from '@ohos.resourceschedule.workScheduler';

let workInfo = {
    workId: 1,
    batteryStatus:workScheduler.BatteryStatus.BATTERY_STATUS_LOW,
    isRepeat: false,
    isPersisted: true,
    bundleName: "com.example.myapplication",
    abilityName: "MyExtension",
    parameters: {
      mykey0: 1,
      mykey1: "string value",
      mykey2: true,
      mykey3: 1.5
  }
}
try{
  workScheduler.stopWork(workInfo, false);
  console.info('workschedulerLog stopWork success');
} catch (error) {
  console.error(`workschedulerLog stopWork failed. code is ${error.code} message is ${error.message}`);
}

5、获取指定延迟任务

try{
  workScheduler.getWorkStatus(50, (error, res) => {
    if (error) {
      console.error(`workschedulerLog getWorkStatus failed. code is ${error.code} message is ${error.message}`);
    } else {
      for (let item in res) {
        console.info(`workschedulerLog getWorkStatus success, ${item} is: ${res[item]}`);
      }
    }
  });
} catch (error) {
  console.error(`workschedulerLog getWorkStatus failed. code is ${error.code} message is ${error.message}`);
}

6、获取所有延迟任务

try{
  workScheduler.obtainAllWorks((error, res) =>{
    if (error) {
      console.error(`workschedulerLog obtainAllWorks failed. code is ${error.code} message is ${error.message}`);
    } else {
      console.info(`workschedulerLog obtainAllWorks success, data is: ${JSON.stringify(res)}`);
    }
  });
} catch (error) {
  console.error(`workschedulerLog obtainAllWorks failed. code is ${error.code} message is ${error.message}`);
}

7、停止并清除任务

try{
  workScheduler.stopAndClearWorks();
  console.info(`workschedulerLog stopAndClearWorks success`);
} catch (error) {
  console.error(`workschedulerLog stopAndClearWorks failed. code is ${error.code} message is ${error.message}`);
}

8、判断上次执行是否超时

try{
  workScheduler.isLastWorkTimeOut(500, (error, res) =>{
    if (error) {
      console.error(`workschedulerLog isLastWorkTimeOut failed. code is ${error.code} message is ${error.message}`);
    } else {
      console.info(`workschedulerLog isLastWorkTimeOut success, data is: ${res}`);
    }
  });
} catch (error) {
  console.error(`workschedulerLog isLastWorkTimeOut failed. code is ${error.code} message is ${error.message}`);
}