@ohos.power (Power Management)

The power module provides APIs for rebooting and shutting down the system, as well as querying the screen status.

NOTE

The initial APIs of this module are supported since API version 7. Newly added APIs will be marked with a superscript to indicate their earliest API version.

Modules to Import

import power from '@ohos.power';

power.shutdown

shutdown(reason: string): void

Shuts down the system.

System API: This is a system API.

Required permission: ohos.permission.REBOOT

System capability: SystemCapability.PowerManager.PowerManager.Core

Parameters

Error codes

For details about the error codes, see Power Manager Error Codes.

Example

try {
    power.shutdown('shutdown_test');
} catch(err) {
    console.error('shutdown failed, err: ' + err);
}

power.reboot⁹⁺

reboot(reason: string): void

Reboots the system.

System API: This is a system API.

Required permission: ohos.permission.REBOOT

System capability: SystemCapability.PowerManager.PowerManager.Core

Parameters

Error codes

For details about the error codes, see Power Manager Error Codes.

Example

try {
    power.reboot('reboot_test');
} catch(err) {
    console.error('reboot failed, err: ' + err);
}

power.isActive⁹⁺

isActive(): boolean

Checks whether the current device is active. In the active state, the screen is on if the device has a screen and the device is not in sleep state if the device does not have a screen.

System capability: SystemCapability.PowerManager.PowerManager.Core

Error codes

For details about the error codes, see Power Manager Error Codes.

Example

try {
    let isActive = power.isActive();
    console.info('power is active: ' + isActive);
} catch(err) {
    console.error('check active status failed, err: ' + err);
}

power.wakeup⁹⁺

wakeup(detail: string): void

Wakes up a device.

System API: This is a system API.

System capability: SystemCapability.PowerManager.PowerManager.Core

Parameters

Error codes

For details about the error codes, see Power Manager Error Codes.

Example

try {
    power.wakeup('wakeup_test');
} catch(err) {
    console.error('wakeup failed, err: ' + err);
}

power.suspend⁹⁺

suspend(isImmediate?: boolean): void

Hibernates a device.

System API: This is a system API.

System capability: SystemCapability.PowerManager.PowerManager.Core

Parameters

Error codes

For details about the error codes, see Power Manager Error Codes.

Example

try {
    power.suspend();
} catch(err) {
    console.error('suspend failed, err: ' + err);
}

power.getPowerMode⁹⁺

getPowerMode(): DevicePowerMode

Obtains the power mode of this device.

System capability: SystemCapability.PowerManager.PowerManager.Core

Return value

Error codes

For details about the error codes, see Power Manager Error Codes.

Example

try {
    let mode = power.getPowerMode();
    console.info('power mode: ' + mode);
} catch(err) {
    console.error('get power mode failed, err: ' + err);
}

power.setPowerMode⁹⁺

setPowerMode(mode: DevicePowerMode, callback: AsyncCallback<void>): void

Sets the power mode of this device. This API uses an asynchronous callback to return the result.

System API: This is a system API.

Required permission: ohos.permission.POWER_OPTIMIZATION

System capability: SystemCapability.PowerManager.PowerManager.Core

Parameters

Error codes

For details about the error codes, see Power Manager Error Codes.

Example

power.setPowerMode(power.DevicePowerMode.MODE_PERFORMANCE, (err: Error) => {
    if (typeof err === 'undefined') {
        console.info('set power mode to MODE_PERFORMANCE');
    } else {
        console.error('set power mode failed, err: ' + err);
    }
});

power.setPowerMode⁹⁺

setPowerMode(mode: DevicePowerMode): Promise<void>

Sets the power mode of this device. This API uses a promise to return the result.

System API: This is a system API.

Required permission: ohos.permission.POWER_OPTIMIZATION

System capability: SystemCapability.PowerManager.PowerManager.Core

Parameters

Return value

Error codes

For details about the error codes, see Power Manager Error Codes.

Example

power.setPowerMode(power.DevicePowerMode.MODE_PERFORMANCE)
.then(() => {
    console.info('set power mode to MODE_PERFORMANCE');
})
.catch((err : Error)=> {
    console.error('set power mode failed, err: ' + err);
});

power.isStandby¹⁰⁺

isStandby(): boolean

Checks whether the device is in standby mode.

System capability: SystemCapability.PowerManager.PowerManager.Core

Return value

Error codes

For details about the error codes, see Power Manager Error Codes.

Example

try {
    let isStandby = power.isStandby();
    console.info('device is in standby: ' + isStandby);
} catch(err) {
    console.error('check isStandby failed, err: ' + err);
}

power.rebootDevice^(deprecated)

rebootDevice(reason: string): void

NOTE
This API is supported since API version 7 and is deprecated since API version 9. You are advised to use power.reboot. The substitute API is available only for system applications.

Reboots the system.

Required permission: ohos.permission.REBOOT

System capability: SystemCapability.PowerManager.PowerManager.Core

Parameters

Example

power.rebootDevice('reboot_test');

power.isScreenOn^(deprecated)

isScreenOn(callback: AsyncCallback<boolean>): void

NOTE
This API is deprecated since API version 9. You are advised to use power.isActive.

Checks the screen status of the current device. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.PowerManager.PowerManager.Core

Parameters

Example

power.isScreenOn((err: Error, data: boolean) => {
    if (typeof err === 'undefined') {
        console.info('screen on status is ' + data);
    } else {
        console.error('check screen status failed, err: ' + err);
    }
})

power.isScreenOn^(deprecated)

isScreenOn(): Promise<boolean>

NOTE
This API is deprecated since API version 9. You are advised to use power.isActive.

Checks the screen status of the current device. This API uses a promise to return the result.

System capability: SystemCapability.PowerManager.PowerManager.Core

Return value |Type |Description | |———————-|————————————————–| |Promise<boolean>|Promise used to return the result. The value true indicates that the screen is on, and the value false indicates the opposite.|

Example

power.isScreenOn()
.then((data: boolean) => {
    console.info('screen on status is ' + data);
})
.catch((err: { code: number, message: string }) => {
    console.error('check screen status failed, err: ' + err);
})

DevicePowerMode⁹⁺

Enumerates power modes.

System capability: SystemCapability.PowerManager.PowerManager.Core

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