# @ohos.app.ability.Configuration (Configuration)

The **Configuration** module defines environment change information. **Configuration** is an interface definition and is used only for field declaration.

> **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

```ts
import { Configuration } from '@kit.AbilityKit';
```

## Properties

**System capability**: SystemCapability.Ability.AbilityBase

| Name| Type| Read-only| Optional| Description|
| -------- | -------- | -------- | -------- | -------- |
| language | string | No| Yes| Language of the application, for example, **zh**.<br>**Atomic service API**: This API can be used in atomic services since API version 11.|
| colorMode | [ConfigurationConstant.ColorMode](js-apis-app-ability-configurationConstant.md#colormode) | No| Yes| Color mode. The default value is **COLOR_MODE_LIGHT**. The options are as follows:<br>- **COLOR_MODE_NOT_SET**: The color mode is not set.<br>- **COLOR_MODE_LIGHT**: light mode.<br>- **COLOR_MODE_DARK**: dark mode.<br>**Atomic service API**: This API can be used in atomic services since API version 11.|
| direction | [ConfigurationConstant.Direction](js-apis-app-ability-configurationConstant.md#direction) | No| Yes| Screen orientation. The options are as follows:<br>- **DIRECTION_NOT_SET**: The screen orientation is not set.<br>- **DIRECTION_HORIZONTAL**: horizontal direction.<br>- **DIRECTION_VERTICAL**: vertical direction.<br>**Atomic service API**: This API can be used in atomic services since API version 11.|
| screenDensity  | [ConfigurationConstant.ScreenDensity](js-apis-app-ability-configurationConstant.md#screendensity) | No| Yes| Pixel density of the screen. The options are as follows:<br>- **SCREEN_DENSITY_NOT_SET**: The pixel density is not set.<br>- **SCREEN_DENSITY_SDPI**: 120.<br>- **SCREEN_DENSITY_MDPI**: 160.<br>- **SCREEN_DENSITY_LDPI**: 240.<br>- **SCREEN_DENSITY_XLDPI**: 320.<br>- **SCREEN_DENSITY_XXLDPI**: 480.<br>- **SCREEN_DENSITY_XXXLDPI**: 640.<br>**Atomic service API**: This API can be used in atomic services since API version 11.|
| displayId  | number | No| Yes| ID of the display where the application is located.<br>**Atomic service API**: This API can be used in atomic services since API version 11.|
| hasPointerDevice  | boolean | No| Yes| Whether a pointer device, such as a keyboard, mouse, or touchpad, is connected.<br>**Atomic service API**: This API can be used in atomic services since API version 11.|
| fontId<sup>14+<sup> | number | No| Yes| Unique ID of the current system font.<br>**Atomic service API**: This API can be used in atomic services since API version 14.|
| fontSizeScale<sup>12+<sup> | number | No| Yes| Font size scale ratio. The value is a non-negative number. The default value is **1**.<br>**Atomic service API**: This API can be used in atomic services since API version 12.|
| fontWeightScale<sup>12+<sup> | number | No| Yes| Font weight scale ratio. The value is a non-negative number. The default value is **1**.<br>**Atomic service API**: This API can be used in atomic services since API version 12.|
| mcc<sup>12+<sup> | string | No | Yes| Mobile network code (MNC).<br>**Atomic service API**: This API can be used in atomic services since API version 12.|
| mnc<sup>12+<sup> | string | No | Yes| Mobile country code (MCC).<br>**Atomic service API**: This API can be used in atomic services since API version 12.|

**Example**

```ts
import { UIAbility, AbilityConstant, EnvironmentCallback, Want } from '@kit.AbilityKit';
import { BusinessError } from '@kit.BasicServicesKit';

export default class EntryAbility extends UIAbility {
  onCreate(want: Want, launchParam: AbilityConstant.LaunchParam) {
    let envCallback: EnvironmentCallback = {
      onConfigurationUpdated(config) {
        console.info(`envCallback onConfigurationUpdated success: ${JSON.stringify(config)}`);
        let language = config.language;
        let colorMode = config.colorMode;
        let direction = config.direction;
        let screenDensity = config.screenDensity;
        let displayId = config.displayId;
        let hasPointerDevice = config.hasPointerDevice;
        let fontId = config.fontId;
        let fontSizeScale = config.fontSizeScale;
        let fontWeightScale = config.fontWeightScale;
        let mcc = config.mcc;
        let mnc = config.mnc;
      },
      onMemoryLevel(level) {
        console.log(`onMemoryLevel level: ${level}`);
      }
    };
    try {
      let applicationContext = this.context.getApplicationContext();
      let callbackId = applicationContext.on('environment', envCallback);
      console.log(`callbackId: ${callbackId}`);
    } catch (paramError) {
      console.error(`error: ${(paramError as BusinessError).code}, ${(paramError as BusinessError).message}`);
    }
  }
}
```