@ohos.resourceschedule.backgroundTaskManager (Background Task Management)

The backgroundTaskManager module provides APIs to request background tasks. You can use the APIs to request transient tasks, continuous tasks, or efficiency resources to prevent the application process from being terminated or suspended when your application is switched to the background.

NOTE

The initial APIs of this module are supported since API version 9. Newly added APIs will be marked with a superscript to indicate their earliest API version.

Modules to Import

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

backgroundTaskManager.requestSuspendDelay

requestSuspendDelay(reason: string, callback: Callback<void>): DelaySuspendInfo

Requests a transient task.

NOTE

The maximum duration of a transient task is 3 minutes in normal cases. In the case of a low battery, the maximum duration is decreased to 1 minute.

System capability: SystemCapability.ResourceSchedule.BackgroundTaskManager.TransientTask

Parameters

Return value

Error codes

For details about the error codes, see backgroundTaskManager Error Codes.

Example

import { BusinessError } from '@ohos.base';

let myReason = 'test requestSuspendDelay';
try {
    let delayInfo = backgroundTaskManager.requestSuspendDelay(myReason, () => {
        console.info("Request suspension delay will time out.");
    })
    let id = delayInfo.requestId;
    let time = delayInfo.actualDelayTime;
    console.info("The requestId is: " + id);
    console.info("The actualDelayTime is: " + time);
} catch (error) {
    console.error(`requestSuspendDelay failed. code is ${(error as BusinessError).code} message is ${(error as BusinessError).message}`);
}

backgroundTaskManager.getRemainingDelayTime

getRemainingDelayTime(requestId: number, callback: AsyncCallback<number>): void

Obtains the remaining time of a transient task. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.ResourceSchedule.BackgroundTaskManager.TransientTask

Parameters

Error codes

For details about the error codes, see backgroundTaskManager Error Codes.

Example

import { BusinessError } from '@ohos.base';

let id = 1;
backgroundTaskManager.getRemainingDelayTime(id, (error: BusinessError, res: number) => {
    if(error) {
        console.error(`callback => Operation getRemainingDelayTime failed. code is ${error.code} message is ${error.message}`);
    } else {
        console.log('callback => Operation getRemainingDelayTime succeeded. Data: ' + JSON.stringify(res));
    }
})

backgroundTaskManager.getRemainingDelayTime

getRemainingDelayTime(requestId: number): Promise<number>

Obtains the remaining time of a transient task. This API uses a promise to return the result.

System capability: SystemCapability.ResourceSchedule.BackgroundTaskManager.TransientTask

Parameters

Return value

Error codes

For details about the error codes, see backgroundTaskManager Error Codes.

Example

import { BusinessError } from '@ohos.base';

let id = 1;
backgroundTaskManager.getRemainingDelayTime(id).then((res: number) => {
    console.log('promise => Operation getRemainingDelayTime succeeded. Data: ' + JSON.stringify(res));
}).catch((error: BusinessError) => {
    console.error(`promise => Operation getRemainingDelayTime failed. code is ${error.code} message is ${error.message}`);
})

backgroundTaskManager.cancelSuspendDelay

cancelSuspendDelay(requestId: number): void

Cancels a transient task.

System capability: SystemCapability.ResourceSchedule.BackgroundTaskManager.TransientTask

Parameters

Error codes

For details about the error codes, see backgroundTaskManager Error Codes.

Example

import { BusinessError } from '@ohos.base';

let id = 1;
try {
  backgroundTaskManager.cancelSuspendDelay(id);
} catch (error) {
  console.error(`cancelSuspendDelay failed. code is ${(error as BusinessError).code} message is ${(error as BusinessError).message}`);
}

backgroundTaskManager.startBackgroundRunning

startBackgroundRunning(context: Context, bgMode: BackgroundMode, wantAgent: WantAgent, callback: AsyncCallback<void>): void

Requests a continuous task. This API uses an asynchronous callback to return the result.

Required permissions: ohos.permission.KEEP_BACKGROUND_RUNNING

System capability: SystemCapability.ResourceSchedule.BackgroundTaskManager.ContinuousTask

Parameters

Error codes

For details about the error codes, see backgroundTaskManager Error Codes.

Example

import UIAbility from '@ohos.app.ability.UIAbility';
import backgroundTaskManager from '@ohos.resourceschedule.backgroundTaskManager';  
import wantAgent, { WantAgent } from '@ohos.app.ability.wantAgent';
import Want from '@ohos.app.ability.Want';
import AbilityConstant from '@ohos.app.ability.AbilityConstant';
import { BusinessError } from '@ohos.base';

function callback(error: BusinessError, data: void) {
    if (error) {
        console.error(`Operation startBackgroundRunning failed. code is ${error.code} message is ${error.message}`);
    } else {
        console.info("Operation startBackgroundRunning succeeded");
    }
}

export default class EntryAbility extends UIAbility {
    onCreate(want: Want, launchParam: AbilityConstant.LaunchParam) {
        let wantAgentInfo: wantAgent.WantAgentInfo = {
            // List of operations to be executed after the notification is clicked.
            wants: [
                {
                    bundleName: "com.example.myapplication",
                    abilityName: "EntryAbility"
                }
            ],
            // Type of the operation to perform after the notification is clicked.
            actionType: wantAgent.OperationType.START_ABILITY,
            // Custom request code.
            requestCode: 0,
            // Execution attribute of the operation to perform after the notification is clicked.
            wantAgentFlags: [wantAgent.WantAgentFlags.UPDATE_PRESENT_FLAG]
        };

        try {
            // Obtain the WantAgent object by using the getWantAgent API of the wantAgent module.
            wantAgent.getWantAgent(wantAgentInfo).then((wantAgentObj: WantAgent) => {
                try {
                    backgroundTaskManager.startBackgroundRunning(this.context,
                        backgroundTaskManager.BackgroundMode.LOCATION, wantAgentObj, callback)
                } catch (error) {
                    console.error(`Operation startBackgroundRunning failed. code is ${(error as BusinessError).code} message is ${(error as BusinessError).message}`);
                }
            });
        } catch (error) {
            console.error(`Operation getWantAgent failed. code is ${(error as BusinessError).code} message is ${(error as BusinessError).message}`);
        }
    }
};

backgroundTaskManager.startBackgroundRunning

startBackgroundRunning(context: Context, bgMode: BackgroundMode, wantAgent: WantAgent): Promise<void>

Requests a continuous task. This API uses a promise to return the result.

Required permissions: ohos.permission.KEEP_BACKGROUND_RUNNING

System capability: SystemCapability.ResourceSchedule.BackgroundTaskManager.ContinuousTask

Parameters

Return value

Error codes

For details about the error codes, see backgroundTaskManager Error Codes.

Example

import UIAbility from '@ohos.app.ability.UIAbility';
import backgroundTaskManager from '@ohos.resourceschedule.backgroundTaskManager'; 
import wantAgent, { WantAgent } from '@ohos.app.ability.wantAgent';
import Want from '@ohos.app.ability.Want';
import AbilityConstant from '@ohos.app.ability.AbilityConstant';
import { BusinessError } from '@ohos.base';

export default class EntryAbility extends UIAbility {
    onCreate(want: Want, launchParam: AbilityConstant.LaunchParam) {
        let wantAgentInfo: wantAgent.WantAgentInfo = {
            // List of operations to be executed after the notification is clicked.
            wants: [
                {
                    bundleName: "com.example.myapplication",
                    abilityName: "EntryAbility"
                }
            ],
            // Type of the operation to perform after the notification is clicked.
            actionType: wantAgent.OperationType.START_ABILITY,
            // Custom request code.
            requestCode: 0,
            // Execution attribute of the operation to perform after the notification is clicked.
            wantAgentFlags: [wantAgent.WantAgentFlags.UPDATE_PRESENT_FLAG]
        };

        try {
            // Obtain the WantAgent object by using the getWantAgent API of the wantAgent module.
            wantAgent.getWantAgent(wantAgentInfo).then((wantAgentObj: WantAgent) => {
                try {
                    backgroundTaskManager.startBackgroundRunning(this.context,
                        backgroundTaskManager.BackgroundMode.LOCATION, wantAgentObj).then(() => {
                        console.info("Operation startBackgroundRunning succeeded");
                    }).catch((error: BusinessError) => {
                        console.error(`Operation startBackgroundRunning failed. code is ${error.code} message is ${error.message}`);
                    });
                } catch (error) {
                    console.error(`Operation startBackgroundRunning failed. code is ${(error as BusinessError).code} message is ${(error as BusinessError).message}`);
                }
            });
        } catch (error) {
            console.error(`Operation getWantAgent failed. code is ${(error as BusinessError).code} message is ${(error as BusinessError).message}`);
        }
    }
};

backgroundTaskManager.stopBackgroundRunning

stopBackgroundRunning(context: Context, callback: AsyncCallback<void>): void

Cancels a continuous task. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.ResourceSchedule.BackgroundTaskManager.ContinuousTask

Parameters

Error codes

For details about the error codes, see backgroundTaskManager Error Codes.

Example

import UIAbility from '@ohos.app.ability.UIAbility';
import backgroundTaskManager from '@ohos.resourceschedule.backgroundTaskManager';  
import Want from '@ohos.app.ability.Want';
import AbilityConstant from '@ohos.app.ability.AbilityConstant';
import { BusinessError } from '@ohos.base';

function callback(error: BusinessError, data: void) {
    if (error) {
        console.error(`Operation stopBackgroundRunning failed. code is ${error.code} message is ${error.message}`);
    } else {
        console.info("Operation stopBackgroundRunning succeeded");
    }
}

export default class EntryAbility extends UIAbility {
    onCreate(want: Want, launchParam: AbilityConstant.LaunchParam) {
        try {
            backgroundTaskManager.stopBackgroundRunning(this.context, callback);
        } catch (error) {
            console.error(`Operation stopBackgroundRunning failed. code is ${(error as BusinessError).code} message is ${(error as BusinessError).message}`);
        }
    }
};

backgroundTaskManager.stopBackgroundRunning

stopBackgroundRunning(context: Context): Promise<void>

Cancels a continuous task. This API uses a promise to return the result.

System capability: SystemCapability.ResourceSchedule.BackgroundTaskManager.ContinuousTask

Parameters

Return value

Error codes

For details about the error codes, see backgroundTaskManager Error Codes.

Example

import UIAbility from '@ohos.app.ability.UIAbility';
import backgroundTaskManager from '@ohos.resourceschedule.backgroundTaskManager';  
import Want from '@ohos.app.ability.Want';
import AbilityConstant from '@ohos.app.ability.AbilityConstant';
import { BusinessError } from '@ohos.base';

export default class EntryAbility extends UIAbility {
    onCreate(want: Want, launchParam: AbilityConstant.LaunchParam) {
        try {
            backgroundTaskManager.stopBackgroundRunning(this.context).then(() => {
                console.info("Operation stopBackgroundRunning succeeded");
            }).catch((error: BusinessError) => {
                console.error(`Operation stopBackgroundRunning failed. code is ${error.code} message is ${error.message}`);
            });
        } catch (error) {
            console.error(`Operation stopBackgroundRunning failed. code is ${(error as BusinessError).code} message is ${(error as BusinessError).message}`);
        }
    }
};

DelaySuspendInfo

Defines the information about the transient task.

System capability: SystemCapability.ResourceSchedule.BackgroundTaskManager.TransientTask

BackgroundMode

Enumerates the continuous task modes.

System capability: SystemCapability.ResourceSchedule.BackgroundTaskManager.ContinuousTask