1# @ohos.app.ability.Configuration (Configuration)
2
3The **Configuration** module defines environment change information. **Configuration** is an interface definition and is used only for field declaration.
4
5> **NOTE**
6>
7> 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.
8
9## Modules to Import
10
11```ts
12import { Configuration } from '@kit.AbilityKit';
13```
14
15## Properties
16
17**System capability**: SystemCapability.Ability.AbilityBase
18
19| Name| Type| Read-only| Optional| Description|
20| -------- | -------- | -------- | -------- | -------- |
21| 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.|
22| 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.|
23| 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.|
24| 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.|
25| 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.|
26| 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.|
27| 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.|
28| 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.|
29| 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.|
30| 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.|
31| 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.|
32
33**Example**
34
35```ts
36import { UIAbility, AbilityConstant, EnvironmentCallback, Want } from '@kit.AbilityKit';
37import { BusinessError } from '@kit.BasicServicesKit';
38
39export default class EntryAbility extends UIAbility {
40  onCreate(want: Want, launchParam: AbilityConstant.LaunchParam) {
41    let envCallback: EnvironmentCallback = {
42      onConfigurationUpdated(config) {
43        console.info(`envCallback onConfigurationUpdated success: ${JSON.stringify(config)}`);
44        let language = config.language;
45        let colorMode = config.colorMode;
46        let direction = config.direction;
47        let screenDensity = config.screenDensity;
48        let displayId = config.displayId;
49        let hasPointerDevice = config.hasPointerDevice;
50        let fontId = config.fontId;
51        let fontSizeScale = config.fontSizeScale;
52        let fontWeightScale = config.fontWeightScale;
53        let mcc = config.mcc;
54        let mnc = config.mnc;
55      },
56      onMemoryLevel(level) {
57        console.log(`onMemoryLevel level: ${level}`);
58      }
59    };
60    try {
61      let applicationContext = this.context.getApplicationContext();
62      let callbackId = applicationContext.on('environment', envCallback);
63      console.log(`callbackId: ${callbackId}`);
64    } catch (paramError) {
65      console.error(`error: ${(paramError as BusinessError).code}, ${(paramError as BusinessError).message}`);
66    }
67  }
68}
69```
70