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

**AbilityStage** is a runtime class for HAP files.

**AbilityStage** notifies you of when you can perform HAP initialization such as resource pre-loading and thread creation during the HAP loading.

> **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. 
> The APIs of this module can be used only in the stage model.

## Modules to Import

```ts
import AbilityStage from '@ohos.app.ability.AbilityStage';
```

## AbilityStage.onCreate

onCreate(): void

Called when the application is created.

**System capability**: SystemCapability.Ability.AbilityRuntime.Core

**Example**
    
```ts
import AbilityStage from '@ohos.app.ability.AbilityStage';

class MyAbilityStage extends AbilityStage {
    onCreate() {
        console.log('MyAbilityStage.onCreate is called');
    }
}
```


## AbilityStage.onAcceptWant

onAcceptWant(want: Want): string

Called when a specified ability is started.

**System capability**: SystemCapability.Ability.AbilityRuntime.Core

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| want | [Want](js-apis-app-ability-want.md) | Yes| Want information about the target ability, such as the ability name and bundle name.|

**Return value**

  | Type| Description| 
  | -------- | -------- |
  | string | Ability ID. If the ability with this ID has been started, no new instance is created and the ability is placed at the top of the stack. Otherwise, a new instance is created and started.| 

**Example**
    
```ts
import AbilityStage from '@ohos.app.ability.AbilityStage';
import Want from '@ohos.app.ability.Want';

class MyAbilityStage extends AbilityStage {
    onAcceptWant(want: Want) {
        console.log('MyAbilityStage.onAcceptWant called');
        return 'com.example.test';
    }
}
```

## AbilityStage.onNewProcessRequest<sup>11+</sup>

onNewProcessRequest(want: Want): string

Called when the UIAbility is started in the specified process.

**System capability**: SystemCapability.Ability.AbilityRuntime.Core

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| want | [Want](js-apis-app-ability-want.md) | Yes| Want information about the target ability, such as the ability name and bundle name.|

**Return value**

| Type| Description| 
| -------- | -------- |
| string | Process ID. If the process with this ID has been created, the ability runs in the process. Otherwise, a new process is created and the ability runs in it.| 

**Example**
    
```ts
import AbilityStage from '@ohos.app.ability.AbilityStage';
import Want from '@ohos.app.ability.Want';

class MyAbilityStage extends AbilityStage {
    onNewProcessRequest(want: Want) {
        console.log('MyAbilityStage.onNewProcessRequest called');
        return 'com.example.test';
    }
}
```


## AbilityStage.onConfigurationUpdate

onConfigurationUpdate(newConfig: Configuration): void

Called when the global configuration is updated.

**System capability**: SystemCapability.Ability.AbilityRuntime.Core

**Parameters**

  | Name| Type| Mandatory| Description| 
  | -------- | -------- | -------- | -------- |
  | newConfig | [Configuration](js-apis-app-ability-configuration.md) | Yes| Callback invoked when the global configuration is updated. The global configuration indicates the configuration of the environment where the application is running and includes the language and color mode.| 

**Example**
    
```ts
import AbilityStage from '@ohos.app.ability.AbilityStage';
import { Configuration } from '@ohos.app.ability.Configuration';

class MyAbilityStage extends AbilityStage {
    onConfigurationUpdate(config: Configuration) {
        console.log('onConfigurationUpdate, language: ${config.language}');
    }
}
```

## AbilityStage.onMemoryLevel

onMemoryLevel(level: AbilityConstant.MemoryLevel): void

Called when the system has decided to adjust the memory level. For example, this API can be used when there is not enough memory to run as many background processes as possible.

**System capability**: SystemCapability.Ability.AbilityRuntime.Core

**Parameters**

  | Name| Type| Mandatory| Description| 
  | -------- | -------- | -------- | -------- |
  | level | [AbilityConstant.MemoryLevel](js-apis-app-ability-abilityConstant.md#abilityconstantmemorylevel) | Yes| Memory level that indicates the memory usage status. When the specified memory level is reached, a callback will be invoked and the system will start adjustment.| 

**Example**
    
```ts
import AbilityStage from '@ohos.app.ability.AbilityStage';
import AbilityConstant from '@ohos.app.ability.AbilityConstant';

class MyAbilityStage extends AbilityStage {
    onMemoryLevel(level: AbilityConstant.MemoryLevel) {
        console.log(`onMemoryLevel, level: ${JSON.stringify(level)}`);
    } 
}
```

## AbilityStage.context

context: AbilityStageContext

Defines the context of **AbilityStage**.

**System capability**: SystemCapability.Ability.AbilityRuntime.Core

| Name     | Type                       | Description                                                        |
| ----------- | --------------------------- | ------------------------------------------------------------ |
| context  | [AbilityStageContext](js-apis-inner-application-abilityStageContext.md) | The context is obtained in the callback invoked when initialization is performed during ability startup.|

**Example**
    
```ts
import AbilityStage from '@ohos.app.ability.AbilityStage';

export default class MyAbilityStage extends AbilityStage {
  onCreate() {
    let abilityStageContext = this.context;
  }
  // ...
}
```