# System Time and Time Zone

The **systemTime** module provides system time and time zone features. You can use the APIs of this module to set and obtain the system time and time zone.

> **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.
>- The APIs of this module are system APIs and cannot be called by third-party applications.

## Modules to Import


```
import systemTime from '@ohos.systemTime';
```


## systemTime.setTime

setTime(time : number, callback : AsyncCallback<void>) : void

Sets the system time. This API uses an asynchronous callback to return the result.

**Required permissions**: ohos.permission.SET_TIME

**System capability**: SystemCapability.MiscServices.Time

**Parameters**

| Name  | Type                     | Mandatory| Description                                      |
| -------- | ------------------------- | ---- | ------------------------------------------ |
| time     | number                    | Yes  | Timestamp to set, in milliseconds. |
| callback | AsyncCallback<void> | Yes  | Callback used to return the result.|

**Example**

  ```js
  // Set the system time to 2021-01-20 02:36:25.
  var time = 1611081385000;
  systemTime.setTime(time, (error, data) => {
      if (error) {
          console.error(`failed to systemTime.setTime because ` + JSON.stringify(error));
          return;
      }
      console.log(`systemTime.setTime success data : ` + JSON.stringify(data));
  });
  ```


## systemTime.setTime

setTime(time : number) : Promise<void>

Sets the system time. This API uses a promise to return the result.

**Required permissions**: ohos.permission.SET_TIME

**System capability**: SystemCapability.MiscServices.Time

**Parameters**

| Name| Type  | Mandatory| Description              |
| ------ | ------ | ---- | ------------------ |
| time   | number | Yes  | Timestamp to set, in milliseconds. |

**Return value**

| Type               | Description                |
| ------------------- | -------------------- |
| Promise<void> | Promise used to return the result.|

**Example**

  ```js
  // Set the system time to 2021-01-20 02:36:25.
  var time = 1611081385000;
  systemTime.setTime(time).then((data) => {
      console.log(`systemTime.setTime success data : ` + JSON.stringify(data));
  }).catch((error) => {
      console.error(`failed to systemTime.setTime because ` + JSON.stringify(error));
  });
  ```


## systemTime.getCurrentTime<sup>8+</sup>

getCurrentTime(isNano?: boolean, callback: AsyncCallback&lt;number&gt;): void

Obtains the time elapsed since the Unix epoch. This API uses an asynchronous callback to return the result.

**System capability**: SystemCapability.MiscServices.Time

**Parameters**

| Name  | Type                       | Mandatory| Description                                                        |
| -------- | --------------------------- | ---- | ------------------------------------------------------------ |
| isNano   | boolean                     | No  | Whether the time to return is in nanoseconds.<br>- **true**: in nanoseconds.<br>- **false**: in milliseconds. |
| callback | AsyncCallback&lt;number&gt; | Yes  | Callback used to return the time.        |

**Example**

  ```js
  systemTime.getCurrentTime(true, (error, data) => {
      if (error) {
          console.error(`failed to systemTime.getCurrentTime because ` + JSON.stringify(error));
          return;
      }
      console.log(`systemTime.getCurrentTime success data : ` + JSON.stringify(data));
  });
  ```


## systemTime.getCurrentTime<sup>8+</sup>

getCurrentTime(isNano?: boolean): Promise&lt;number&gt;

Obtains the time elapsed since the Unix epoch. This API uses a promise to return the result.

**System capability**: SystemCapability.MiscServices.Time

**Parameters**

| Name| Type   | Mandatory| Description                                                        |
| ------ | ------- | ---- | ------------------------------------------------------------ |
| isNano | boolean | No  | Whether the time to return is in nanoseconds.<br>- **true**: in nanoseconds.<br>- **false**: in milliseconds. |

**Return value**

| Type                 | Description                                                        |
| --------------------- | ------------------------------------------------------------ |
| Promise&lt;number&gt; | Promise used to return the time.|

**Example**

  ```js
  systemTime.getCurrentTime().then((data) => {
      console.log(`systemTime.getCurrentTime success data : ` + JSON.stringify(data));
  }).catch((error) => {
      console.error(`failed to systemTime.getCurrentTime because ` + JSON.stringify(error));
  });
  ```


## systemTime.getRealActiveTime<sup>8+</sup>

getRealActiveTime(isNano?: boolean, callback: AsyncCallback&lt;number&gt;): void

Obtains the time elapsed since system start, excluding the deep sleep time. This API uses an asynchronous callback to return the result.

**System capability**: SystemCapability.MiscServices.Time

**Parameters**

| Name  | Type                       | Mandatory| Description                                                        |
| -------- | --------------------------- | ---- | ------------------------------------------------------------ |
| isNano   | boolean                     | No  | Whether the time to return is in nanoseconds.<br>- **true**: in nanoseconds.<br>- **false**: in milliseconds. |
| callback | AsyncCallback&lt;number&gt; | Yes  | Callback used to return the time.|

**Example**

  ```js
  systemTime.getRealActiveTime(true, (error, data) => {
      if (error) {
          console.error(`failed to systemTime.getRealActiveTimebecause ` + JSON.stringify(error));
          return;
      }
      console.log(`systemTime.getRealActiveTime success data : ` + JSON.stringify(data));
  });
  ```


## systemTime.getRealActiveTime<sup>8+</sup>

getRealActiveTime(isNano?: boolean): Promise&lt;number&gt;

Obtains the time elapsed since system start, excluding the deep sleep time. This API uses a promise to return the result.

**System capability**: SystemCapability.MiscServices.Time

**Parameters**

| Name| Type   | Mandatory| Description                                                        |
| ------ | ------- | ---- | ------------------------------------------------------------ |
| isNano | boolean | No  | Whether the time to return is in nanoseconds.<br>- **true**: in nanoseconds.<br>- **false**: in milliseconds. |

**Return value**

| Type                 | Description                                                        |
| --------------------- | ------------------------------------------------------------ |
| Promise&lt;number&gt; | Promise used to return the time.|

**Example**

  ```js
  systemTime.getRealActiveTime().then((data) => {
      console.log(`systemTime.getRealActiveTime success data : ` + JSON.stringify(data));
  }).catch((error) => {
      console.error(`failed to systemTime.getRealActiveTime because ` + JSON.stringify(error));
  });
  ```


## systemTime.getRealTime<sup>8+</sup>

getRealTime(isNano?: boolean, callback: AsyncCallback&lt;number&gt;): void

Obtains the time elapsed since system start, including the deep sleep time. This API uses an asynchronous callback to return the result.

**System capability**: SystemCapability.MiscServices.Time

**Parameters**

| Name  | Type                       | Mandatory| Description                                                        |
| -------- | --------------------------- | ---- | ------------------------------------------------------------ |
| isNano   | boolean                     | No  | Whether the time to return is in nanoseconds.<br>- **true**: in nanoseconds.<br>- **false**: in milliseconds. |
| callback | AsyncCallback&lt;number&gt; | Yes  | Callback used to return the time.  |

**Example**

  ```js
  systemTime.getRealTime(true, (error, data) => {
      if (error) {
          console.error(`failed to systemTime.getRealTime because ` + JSON.stringify(error));
          return;
      }
      console.log(`systemTime.getRealTime success data: ` + JSON.stringify(data));
  });
  ```


## systemTime.getRealTime<sup>8+</sup>

getRealTime(isNano?: boolean): Promise&lt;number&gt;

Obtains the time elapsed since system start, including the deep sleep time. This API uses a promise to return the result.

**System capability**: SystemCapability.MiscServices.Time

**Parameters**

| Name| Type   | Mandatory| Description                                                        |
| ------ | ------- | ---- | ------------------------------------------------------------ |
| isNano | boolean | No  | Whether the time to return is in nanoseconds.<br>- **true**: in nanoseconds.<br>- **false**: in milliseconds. |

**Return value**

| Type                 | Description                                                        |
| --------------------- | ------------------------------------------------------------ |
| Promise&lt;number&gt; | Promise used to return the time.|

**Example**

  ```js
  systemTime.getRealTime().then((data) => {
      console.log(`systemTime.getRealTime success data: ` + JSON.stringify(data));
  }).catch((error) => {
      console.error(`failed to systemTime.getRealTime because ` + JSON.stringify(error));
  });
  ```


## systemTime.setDate

setDate(date: Date, callback: AsyncCallback&lt;void&gt;): void

Sets the system date. This API uses an asynchronous callback to return the result.

**Required permissions**: ohos.permission.SET_TIME

**System capability**: SystemCapability.MiscServices.Time

**Parameters**

| Name  | Type                     | Mandatory| Description                                      |
| -------- | ------------------------- | ---- | ------------------------------------------ |
| date     | Date                      | Yes  | Target date to set.                                |
| callback | AsyncCallback&lt;void&gt; | Yes  | Callback used to return the result.|

**Example**

  ```js
  var data = new Date("October 13, 2020 11:13:00");
  systemTime.setDate(data,(error, data) => {       
      if (error) {            
      console.error('failed to systemTime.setDate because ' + JSON.stringify(error));           
      return;       
  }        
      console.info('systemTime.setDate success data : ' + JSON.stringify(data));    
  });
  ```


## systemTime.setDate

setDate(date: Date): Promise&lt;void&gt;

Sets the system date. This API uses a promise to return the result.

**Required permissions**: ohos.permission.SET_TIME

**System capability**: SystemCapability.MiscServices.Time

**Parameters**

| Name| Type| Mandatory| Description      |
| ------ | ---- | ---- | ---------- |
| date   | Date | Yes  | Target date to set.|

**Return value**

| Type               | Description                |
| ------------------- | -------------------- |
| Promise&lt;void&gt; | Promise used to return the result.|

**Example**

  ```js
  var data = new Date("October 13, 2020 11:13:00"); 
  systemTime.setDate(data).then((value) => {        
      console.log(`systemTime.setDate success data : ` + JSON.stringify(value));    
  }).catch((error) => {        
      console.error(`failed to systemTime.setDate because: ` + JSON.stringify(error));
  });
  ```


## systemTime.getDate<sup>8+</sup>

getDate(callback: AsyncCallback&lt;Date&gt;): void

Obtains the current system date. This API uses an asynchronous callback to return the result.

**System capability**: SystemCapability.MiscServices.Time

**Parameters**

| Name  | Type                     | Mandatory| Description                        |
| -------- | ------------------------- | ---- | ---------------------------- |
| callback | AsyncCallback&lt;Date&gt; | Yes  | Callback used to return the current system date.|

**Example**

  ```js
  systemTime.getDate((error, data) => {
      if (error) {
          console.error(`failed to systemTime.getDate because ` + JSON.stringify(error));
          return;
      }
      console.log(`systemTime.getDate success data : ` + JSON.stringify(data));
  });
  ```


## systemTime.getDate<sup>8+</sup>

getDate(): Promise&lt;Date&gt;

Obtains the current system date. This API uses a promise to return the result.

**System capability**: SystemCapability.MiscServices.Time

**Return value**

| Type               | Description                                     |
| ------------------- | ----------------------------------------- |
| Promise&lt;Date&gt; | Promise used to return the current system date.|

**Example**

  ```js
  systemTime.getDate().then((data) => {
      console.log(`systemTime.getDate success data : ` + JSON.stringify(data));
  }).catch((error) => {
      console.error(`failed to systemTime.getDate because ` + JSON.stringify(error));
  });
  ```


## systemTime.setTimezone

setTimezone(timezone: string, callback: AsyncCallback&lt;void&gt;): void

Sets the system time zone. This API uses an asynchronous callback to return the result.

**Required permissions**: ohos.permission.SET_TIME_ZONE

**System capability**: SystemCapability.MiscServices.Time

**Parameters**

| Name  | Type                     | Mandatory| Description                                      |
| -------- | ------------------------- | ---- | ------------------------------------------ |
| timezone | string                    | Yes  | System time zone to set.                                |
| callback | AsyncCallback&lt;void&gt; | Yes  | Callback used to return the result.|

**Example**

  ```js
  systemTime.setTimezone('Asia/Shanghai', (error, data) => {       
      if (error) {          
          console.error('failed to systemTime.setTimezone because ' + JSON.stringify(error));         
          return;       
      }       
      console.info('SystemTimePlugin systemTime.setTimezone success data : ' + JSON.stringify(data)); 
  });
  ```


## systemTime.setTimezone

setTimezone(timezone: string): Promise&lt;void&gt;

Sets the system time zone. This API uses a promise to return the result.

**Required permissions**: ohos.permission.SET_TIME_ZONE

**System capability**: SystemCapability.MiscServices.Time

**Parameters**

| Name  | Type  | Mandatory| Description      |
| -------- | ------ | ---- | ---------- |
| timezone | string | Yes  | System time zone to set.|

**Return value**

| Type               | Description                |
| ------------------- | -------------------- |
| Promise&lt;void&gt; | Promise used to return the result.|

**Example**

  ```js
  systemTime.setTimezone('Asia/Shanghai').then((data) => {        
      console.log(`systemTime.setTimezone success data : ` + JSON.stringify(data));     
  }).catch((error) => {        
      console.error(`failed to systemTime.setTimezone because: ` + JSON.stringify(error));    
  });
  ```


## systemTime.getTimezone<sup>8+</sup>

getTimezone(callback: AsyncCallback&lt;string&gt;): void

Obtains the system time zone. This API uses an asynchronous callback to return the result.

**System capability**: SystemCapability.MiscServices.Time

**Parameters**

| Name  | Type                       | Mandatory| Description                    |
| -------- | --------------------------- | ---- | ------------------------ |
| callback | AsyncCallback&lt;string&gt; | Yes  | Callback used to return the system time zone.|

**Example**

  ```js
  systemTime.getTimezone((error, data) => {
      if (error) {
          console.error(`failed to systemTime.getTimezone because ` + JSON.stringify(error));
          return;
      }
      console.log(`systemTime.getTimezone success data : ` + JSON.stringify(data));
  });
  ```


## systemTime.getTimezone<sup>8+</sup>

getTimezone(): Promise&lt;string&gt;

Obtains the system time zone. This API uses a promise to return the result.

**System capability**: SystemCapability.MiscServices.Time

**Return value**

| Type                 | Description                                 |
| --------------------- | ------------------------------------- |
| Promise&lt;string&gt; | Promise used to return the system time zone.|

**Example**

  ```js
  systemTime.getTimezone().then((data) => {
      console.log(`systemTime.getTimezone success data : ` + JSON.stringify(data));
  }).catch((error) => {
      console.error(`failed to systemTime.getTimezone because ` + JSON.stringify(error));
  });
  ```