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

UIAbility是包含UI界面的应用组件，提供组件创建、销毁、前后台切换等生命周期回调，同时也具备组件协同的能力，组件协同主要提供如下常用功能：

- [Caller](#caller)：由[startAbilityByCall](js-apis-inner-application-uiAbilityContext.md#uiabilitycontextstartabilitybycall)接口返回，CallerAbility(调用者)可使用Caller与CalleeAbility(被调用者)进行通信。
- [Callee](#callee)：UIAbility的内部对象，CalleeAbility(被调用者)可以通过Callee与Caller进行通信。

> **说明：**
>
> 本模块首批接口从API version 9 开始支持。后续版本的新增接口，采用上角标单独标记接口的起始版本。
> 本模块接口仅可在Stage模型下使用。

## 导入模块

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

## 属性

**系统能力**：以下各项对应的系统能力均为SystemCapability.Ability.AbilityRuntime.AbilityCore

| 名称 | 类型 | 可读 | 可写 | 说明 |
| -------- | -------- | -------- | -------- | -------- |
| context | [UIAbilityContext](js-apis-inner-application-uiAbilityContext.md) | 是 | 否 | 上下文。 |
| launchWant | [Want](js-apis-app-ability-want.md) | 是 | 否 | UIAbility启动时的参数。 |
| lastRequestWant | [Want](js-apis-app-ability-want.md) | 是 | 否 | UIAbility最后请求时的参数。|
| callee | [Callee](#callee) | 是 | 否 | 调用Stub（桩）服务对象。|

## UIAbility.onCreate

onCreate(want: Want, launchParam: AbilityConstant.LaunchParam): void;

UIAbility创建时回调，执行初始化业务逻辑操作。

**系统能力**：SystemCapability.Ability.AbilityRuntime.AbilityCore

**参数：**

| 参数名 | 类型 | 必填 | 说明 |
| -------- | -------- | -------- | -------- |
| want | [Want](js-apis-app-ability-want.md) | 是 | 当前UIAbility的Want类型信息，包括ability名称、bundle名称等。 |
| param | [AbilityConstant.LaunchParam](js-apis-app-ability-abilityConstant.md#abilityconstantlaunchparam) | 是 | 创建 ability、上次异常退出的原因信息。 |

**示例：**

  ```ts
  import UIAbility from '@ohos.app.ability.UIAbility';
  import AbilityConstant from '@ohos.app.ability.AbilityConstant';
  import Want from '@ohos.app.ability.Want';

  class MyUIAbility extends UIAbility {
      onCreate(want: Want, launchParam: AbilityConstant.LaunchParam) {
          console.log('onCreate, want: ${want.abilityName}');
      }
  }
  ```


## UIAbility.onWindowStageCreate

onWindowStageCreate(windowStage: window.WindowStage): void

当WindowStage创建后调用。

**系统能力**：SystemCapability.Ability.AbilityRuntime.AbilityCore

**参数：**

| 参数名 | 类型 | 必填 | 说明 |
| -------- | -------- | -------- | -------- |
| windowStage | [window.WindowStage](js-apis-window.md#windowstage9) | 是 | WindowStage相关信息。 |

**示例：**

  ```ts
  import UIAbility from '@ohos.app.ability.UIAbility';
  import window from '@ohos.window';

  class MyUIAbility extends UIAbility {
      onWindowStageCreate(windowStage: window.WindowStage) {
          console.log('onWindowStageCreate');
      }
  }
  ```


## UIAbility.onWindowStageDestroy

onWindowStageDestroy(): void

当WindowStage销毁后调用。

**系统能力**：SystemCapability.Ability.AbilityRuntime.AbilityCore

**示例：**

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

  class MyUIAbility extends UIAbility {
      onWindowStageDestroy() {
          console.log('onWindowStageDestroy');
      }
  }
  ```


## UIAbility.onWindowStageRestore

onWindowStageRestore(windowStage: window.WindowStage): void

当迁移多实例ability时，恢复WindowStage后调用。

**系统能力**：SystemCapability.Ability.AbilityRuntime.AbilityCore

**参数：**

| 参数名 | 类型 | 必填 | 说明 |
| -------- | -------- | -------- | -------- |
| windowStage | [window.WindowStage](js-apis-window.md#windowstage9) | 是 | WindowStage相关信息。 |

**示例：**

  ```ts
  import UIAbility from '@ohos.app.ability.UIAbility';
  import window from '@ohos.window';

  class MyUIAbility extends UIAbility {
      onWindowStageRestore(windowStage: window.WindowStage) {
          console.log('onWindowStageRestore');
      }
  }
  ```


## UIAbility.onDestroy

onDestroy(): void | Promise<void>;

UIAbility生命周期回调，在销毁时回调，执行资源清理等操作。

**系统能力**：SystemCapability.Ability.AbilityRuntime.AbilityCore

**示例：**


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

  class MyUIAbility extends UIAbility {
      onDestroy() {
          console.log('onDestroy');
      }
  }
  ```

在执行完onDestroy生命周期回调后，应用可能会退出，从而可能导致onDestroy中的异步函数未能正确执行，比如异步写入数据库。可以使用异步生命周期，以确保异步onDestroy完成后再继续后续的生命周期。

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

class MyUIAbility extends UIAbility {
    async onDestroy() {
        console.log('onDestroy');
        // 调用异步函数...
    }
}
  ```

## UIAbility.onForeground

onForeground(): void;

UIAbility生命周期回调，当应用从后台转到前台时触发。

**系统能力**：SystemCapability.Ability.AbilityRuntime.AbilityCore

**示例：**

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

  class MyUIAbility extends UIAbility {
      onForeground() {
          console.log('onForeground');
      }
  }
  ```


## UIAbility.onBackground

onBackground(): void;

UIAbility生命周期回调，当应用从前台转到后台时触发。

**系统能力**：SystemCapability.Ability.AbilityRuntime.AbilityCore

**示例：**

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

  class MyUIAbility extends UIAbility {
      onBackground() {
          console.log('onBackground');
      }
  }
  ```


## UIAbility.onContinue

onContinue(wantParam: { [key: string]: Object }): AbilityConstant.OnContinueResult;

当ability迁移准备迁移时触发，保存数据。

**系统能力**：SystemCapability.Ability.AbilityRuntime.AbilityCore

**参数：**

| 参数名 | 类型 | 必填 | 说明 |
| -------- | -------- | -------- | -------- |
| wantParam | {[key: string]: Object} | 是 | want相关参数。 |

**返回值：**

| 类型 | 说明 |
| -------- | -------- |
| [AbilityConstant.OnContinueResult](js-apis-app-ability-abilityConstant.md#abilityconstantoncontinueresult) | 继续的结果。 |

**示例：**

  ```ts
  import UIAbility from '@ohos.app.ability.UIAbility';
  import AbilityConstant from '@ohos.app.ability.AbilityConstant';

  class MyUIAbility extends UIAbility {
      onContinue(wantParams: Record<string, Object>) {
          console.log('onContinue');
          wantParams['myData'] = 'my1234567';
          return AbilityConstant.OnContinueResult.AGREE;
      }
  }
  ```


## UIAbility.onNewWant

onNewWant(want: Want, launchParam: AbilityConstant.LaunchParam): void;

当传入新的Want，ability再次被拉起时会回调执行该方法。

**系统能力**：SystemCapability.Ability.AbilityRuntime.AbilityCore

**参数：**

| 参数名 | 类型 | 必填 | 说明 |
| -------- | -------- | -------- | -------- |
| want | [Want](js-apis-app-ability-want.md) | 是 | Want类型参数，如ability名称，包名等。 |
| launchParam | [AbilityConstant.LaunchParam](js-apis-app-ability-abilityConstant.md#abilityconstantlaunchparam) | 是 | UIAbility启动的原因、上次异常退出的原因信息。 |

**示例：**

  ```ts
  import UIAbility from '@ohos.app.ability.UIAbility';
  import AbilityConstant from '@ohos.app.ability.AbilityConstant';

  class MyUIAbility extends UIAbility {
      onNewWant(want: Want, launchParam: AbilityConstant.LaunchParam) {
          console.log('onNewWant, want: ${want.abilityName}');
          console.log('onNewWant, launchParam: ${JSON.stringify(launchParam)}');
      }
  }
  ```

## UIAbility.onDump

onDump(params: Array\<string>): Array\<string>;

转储客户端信息时调用。

**系统能力**：SystemCapability.Ability.AbilityRuntime.AbilityCore

**参数：**

| 参数名 | 类型 | 必填 | 说明 |
| -------- | -------- | -------- | -------- |
| params | Array\<string> | 是 | 表示命令形式的参数。|

**示例：**

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

  class MyUIAbility extends UIAbility {
      onDump(params: Array<string>) {
          console.log('dump, params: ${JSON.stringify(params)}');
          return ['params'];
      }
  }
  ```


## UIAbility.onSaveState

onSaveState(reason: AbilityConstant.StateType, wantParam : {[key: string]: Object}): AbilityConstant.OnSaveResult;

该API配合[appRecovery](js-apis-app-ability-appRecovery.md)使用。在应用故障时，如果使能了自动保存状态，框架将回调onSaveState保存UIAbility状态。

**系统能力**：SystemCapability.Ability.AbilityRuntime.AbilityCore

**参数：**

| 参数名 | 类型 | 必填 | 说明 |
| -------- | -------- | -------- | -------- |
| reason | [AbilityConstant.StateType](js-apis-app-ability-abilityConstant.md#abilityconstantstatetype) | 是 | 回调保存状态的原因。 |
| wantParam | {[key:&nbsp;string]:&nbsp;Object} | 是 | want相关参数。 |

**返回值：**

| 类型 | 说明 |
| -------- | -------- |
| [AbilityConstant.OnSaveResult](js-apis-app-ability-abilityConstant.md#abilityconstantonsaveresult) | 是否同意保存当前UIAbility的状态。 |

**示例：**

  ```ts
import UIAbility from '@ohos.app.ability.UIAbility';
import AbilityConstant from '@ohos.app.ability.AbilityConstant';

class MyUIAbility extends UIAbility {
    onSaveState(reason: AbilityConstant.StateType, wantParam: Record<string, Object>) {
        console.log('onSaveState');
        wantParam['myData'] = 'my1234567';
        return AbilityConstant.OnSaveResult.RECOVERY_AGREE;
    }
}
  ```

## UIAbility.onShare<sup>10+</sup>

onShare(wantParam:{ [key: string]: Object }): void;

在跨端分享场景下，在UIAbility中设置分享方设备要分享的数据。

**系统能力**：SystemCapability.Ability.AbilityRuntime.AbilityCore

**参数：**

| 参数名 | 类型 | 必填 | 说明 |
| -------- | -------- | -------- | -------- |
| wantParam | {[key:&nbsp;string]:&nbsp;Object} | 是 | 待分享的数据。 |

**示例：**

  ```ts
import UIAbility from '@ohos.app.ability.UIAbility';
import AbilityConstant from '@ohos.app.ability.AbilityConstant';

class MyUIAbility extends UIAbility {
    onShare(wantParams: Record<string, Object>) {
        console.log('onShare');
        wantParams['ohos.extra.param.key.shareUrl'] = 'example.com';
    }
}
  ```

## UIAbility.onPrepareToTerminate<sup>10+</sup>

onPrepareToTerminate(): boolean;

UIAbility生命周期回调，当系统预关闭开关打开后（配置系统参数persist.sys.prepare_terminate为true打开），在UIAbility关闭时触发，可在回调中定义操作来决定是否继续执行关闭UIAbility的操作。如果UIAbility在退出时需要与用户交互确认是否关闭UIAbility，可在此生命周期回调中定义预关闭操作配合[terminateSelf](js-apis-inner-application-uiAbilityContext.md#uiabilitycontextterminateself)接口退出，如弹窗确认是否关闭，并配置预关闭生命周期返回true取消正常关闭。

**需要权限**：ohos.permission.PREPARE_APP_TERMINATE

**系统能力**：SystemCapability.Ability.AbilityRuntime.AbilityCore

**返回值：**

| 类型 | 说明 |
| -- | -- |
| boolean | 是否执行UIAbility关闭操作，返回true表示本次UIAbility关闭流程取消，不再退出，返回false表示UIAbility继续正常关闭。 |

**示例：**

  ```ts
  import UIAbility from '@ohos.app.ability.UIAbility';
  import Want from '@ohos.app.ability.Want';
  import { BusinessError } from '@ohos.base';

  export default class EntryAbility extends UIAbility {
    onPrepareToTerminate() {
      // 开发者定义预关闭动作
      // 例如拉起另一个ability，根据ability处理结果执行异步关闭
      let want: Want = {
        bundleName: "com.example.myapplication",
        moduleName: "entry",
        abilityName: "SecondAbility"
      }
      this.context.startAbilityForResult(want)
        .then((result)=>{
          // 获取ability处理结果，当返回结果的resultCode为0关闭当前UIAbility
          console.log('startAbilityForResult success, resultCode is ' + result.resultCode);
          if (result.resultCode === 0) {
            this.context.terminateSelf();
          }
        }).catch((err: BusinessError)=>{
          // 异常处理
          console.log('startAbilityForResult failed, err:' + JSON.stringify(err));
          this.context.terminateSelf();
        })

      return true; // 已定义预关闭操作后，返回true表示UIAbility取消关闭
    }
  }
  ```

## UIAbility.onBackPressed<sup>10+</sup>

onBackPressed(): boolean;

UIAbility生命周期回调，当UIAbility侧滑返回时触发。根据返回值决定是否销毁UIAbility，默认为销毁UIAbility。

**系统能力**：SystemCapability.Ability.AbilityRuntime.AbilityCore

**返回值：**

| 类型 | 说明 |
| -- | -- |
| boolean | 返回true表示UIAbility将会被移到后台不销毁，返回false表示UIAbility将正常销毁。 |

**示例：**

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

  export default class EntryAbility extends UIAbility {
    onBackPressed() {
      return true;
    }
  }
  ```

## Caller

通用组件Caller通信客户端调用接口, 用来向通用组件服务端发送约定数据。

## Caller.call

call(method: string, data: rpc.Parcelable): Promise&lt;void&gt;;

向通用组件服务端发送约定序列化数据。

**系统能力**：SystemCapability.Ability.AbilityRuntime.AbilityCore

**参数：**

| 参数名 | 类型 | 必填 | 说明 |
| -------- | -------- | -------- | -------- |
| method | string | 是 | 约定的服务端注册事件字符串。 |
| data | [rpc.Parcelable](js-apis-rpc.md#parcelable9) | 是 | 由开发者实现的Parcelable可序列化数据。 |

**返回值：**

| 类型 | 说明 |
| -------- | -------- |
| Promise&lt;void&gt; | Promise形式返回应答。 |

**错误码：**

| 错误码ID | 错误信息 |
| ------- | -------------------------------- |
| 16200001 | Caller released. The caller has been released. |
| 16200002 | Callee invalid. The callee does not exist. |
| 16000050 | Internal error. |

以上错误码详细介绍请参考[errcode-ability](../errorcodes/errorcode-ability.md)。

**示例：**

  ```ts
  import UIAbility from '@ohos.app.ability.UIAbility';
  import { Caller } from '@ohos.app.ability.UIAbility';
  import { BusinessError } from '@ohos.base';
  import window from '@ohos.window';
  import rpc from '@ohos.rpc';

  class MyMessageAble implements rpc.Parcelable { // 自定义的Parcelable数据结构
    name: string
    str: string
    num: number = 1
    constructor(name: string, str: string) {
      this.name = name;
      this.str = str;
    }
    marshalling(messageSequence: rpc.MessageSequence) {
      messageSequence.writeInt(this.num);
      messageSequence.writeString(this.str);
      console.log('MyMessageAble marshalling num[${this.num}] str[${this.str}]');
      return true;
    }
    unmarshalling(messageSequence: rpc.MessageSequence) {
      this.num = messageSequence.readInt();
      this.str = messageSequence.readString();
      console.log('MyMessageAble unmarshalling num[${this.num}] str[${this.str}]');
      return true;
    }
  };
  let method = 'call_Function'; // 约定的通知消息字符串
  let caller: Caller;
  export default class MainUIAbility extends UIAbility {
    onWindowStageCreate(windowStage: window.WindowStage) {
      this.context.startAbilityByCall({
        bundleName: 'com.example.myservice',
        abilityName: 'MainUIAbility',
        deviceId: ''
      }).then((obj) => {
        caller = obj;
        let msg = new MyMessageAble('msg', 'world'); // 参考Parcelable数据定义
        caller.call(method, msg)
          .then(() => {
            console.log('Caller call() called');
          })
          .catch((callErr: BusinessError) => {
            console.log('Caller.call catch error, error.code: ${callErr.code}, error.message: ${callErr.message}');
          });
      }).catch((err: BusinessError) => {
        console.log('Caller GetCaller error, error.code: ${err.code}, error.message: ${err.message}');
      });
    }
  }
  ```


## Caller.callWithResult

callWithResult(method: string, data: rpc.Parcelable): Promise&lt;rpc.MessageSequence&gt;;

向通用组件服务端发送约定序列化数据, 并将服务端返回的约定序列化数据带回。

**系统能力**：SystemCapability.Ability.AbilityRuntime.AbilityCore

**参数：**

| 参数名 | 类型 | 必填 | 说明 |
| -------- | -------- | -------- | -------- |
| method | string | 是 | 约定的服务端注册事件字符串。 |
| data | [rpc.Parcelable](js-apis-rpc.md#parcelable9) | 是 | 由开发者实现的Parcelable可序列化数据。 |

**返回值：**

| 类型 | 说明 |
| -------- | -------- |
| Promise&lt;[rpc.MessageSequence](js-apis-rpc.md#messagesequence9)&gt; | Promise形式返回通用组件服务端应答数据。 |

**错误码：**

| 错误码ID | 错误信息 |
| ------- | -------------------------------- |
| 16200001 | Caller released. The caller has been released. |
| 16200002 | Callee invalid. The callee does not exist. |
| 16000050 | Internal error. |

以上错误码详细介绍请参考[errcode-ability](../errorcodes/errorcode-ability.md)。

**示例：**

  ```ts
  import UIAbility from '@ohos.app.ability.UIAbility';
  import { Caller } from '@ohos.app.ability.UIAbility';
  import { BusinessError } from '@ohos.base';
  import window from '@ohos.window';
  import rpc from '@ohos.rpc';

  class MyMessageAble implements rpc.Parcelable {
    name: string
    str: string
    num: number = 1
    constructor(name: string, str: string) {
      this.name = name;
      this.str = str;
    }
    marshalling(messageSequence: rpc.MessageSequence) {
      messageSequence.writeInt(this.num);
      messageSequence.writeString(this.str);
      console.log('MyMessageAble marshalling num[${this.num}] str[${this.str}]');
      return true;
    }
    unmarshalling(messageSequence: rpc.MessageSequence) {
      this.num = messageSequence.readInt();
      this.str = messageSequence.readString();
      console.log('MyMessageAble unmarshalling num[${this.num] str[${this.str}]');
      return true;
    }
  };
  let method = 'call_Function';
  let caller: Caller;
  export default class MainUIAbility extends UIAbility {
    onWindowStageCreate(windowStage: window.WindowStage) {
      this.context.startAbilityByCall({
        bundleName: 'com.example.myservice',
        abilityName: 'MainUIAbility',
        deviceId: ''
      }).then((obj) => {
        caller = obj;
        let msg = new MyMessageAble(1, 'world');
        caller.callWithResult(method, msg)
          .then((data) => {
            console.log('Caller callWithResult() called');
            let retmsg = new MyMessageAble(0, '');
            data.readParcelable(retmsg);
          })
          .catch((callErr: BusinessError) => {
            console.log('Caller.callWithResult catch error, error.code: ${callErr.code}, error.message: ${callErr.message}');
          });
      }).catch((err: BusinessError) => {
        console.log('Caller GetCaller error, error.code: ${err.code}, error.message: ${err.message}');
      });
    }
  }
  ```


## Caller.release

release(): void;

主动释放通用组件服务端的通信接口。

**系统能力**：SystemCapability.Ability.AbilityRuntime.AbilityCore

**错误码：**

| 错误码ID | 错误信息 |
| ------- | -------------------------------- |
| 16200001 | Caller released. The caller has been released. |
| 16200002 | Callee invalid. The callee does not exist. |

以上错误码详细介绍请参考[errcode-ability](../errorcodes/errorcode-ability.md)。

**示例：**

  ```ts
  import UIAbility from '@ohos.app.ability.UIAbility';
  import { Caller } from '@ohos.app.ability.UIAbility';
  import { BusinessError } from '@ohos.base';
  import window from '@ohos.window';

  let caller: Caller;
  export default class MainUIAbility extends UIAbility {
    onWindowStageCreate(windowStage: window.WindowStage) {
      this.context.startAbilityByCall({
        bundleName: 'com.example.myservice',
        abilityName: 'MainUIAbility',
        deviceId: ''
      }).then((obj) => {
        caller = obj;
        try {
          caller.release();
        } catch (releaseErr) {
          console.log('Caller.release catch error, error.code: ${releaseErr.code}, error.message: ${releaseErr.message}');
        }
      }).catch((err: BusinessError) => {
        console.log('Caller GetCaller error, error.code: ${err.code}, error.message: ${err.message}');
      });
    }
  }
  ```

## Caller.onRelease

 onRelease(callback: OnReleaseCallback): void;

注册通用组件服务端Stub（桩）断开监听通知。

**系统能力**：SystemCapability.Ability.AbilityRuntime.AbilityCore

**错误码：**

| 错误码ID | 错误信息 |
| ------- | -------------------------------- |
| 16200001 | Caller released. The caller has been released. |

以上错误码详细介绍请参考[errcode-ability](../errorcodes/errorcode-ability.md)。

**参数：**

| 参数名 | 类型 | 必填 | 说明 |
| -------- | -------- | -------- | -------- |
| callback | [OnReleaseCallback](#onreleasecallback) | 是 | 返回onRelease回调结果。 |

**示例：**

  ```ts
  import UIAbility from '@ohos.app.ability.UIAbility';
  import { Caller } from '@ohos.app.ability.UIAbility';
  import { BusinessError } from '@ohos.base';
  import window from '@ohos.window';

  let caller: Caller;
  export default class MainUIAbility extends UIAbility {
    onWindowStageCreate(windowStage: window.WindowStage) {
      this.context.startAbilityByCall({
        bundleName: 'com.example.myservice',
        abilityName: 'MainUIAbility',
        deviceId: ''
      }).then((obj) => {
          caller = obj;
          try {
            caller.onRelease((str) => {
                console.log(' Caller OnRelease CallBack is called ${str}');
            });
          } catch (error) {
            console.log('Caller.onRelease catch error, error.code: $error.code}, error.message: ${error.message}');
          }
      }).catch((err: BusinessError) => {
        console.log('Caller GetCaller error, error.code: ${err.code}, error.message: ${err.message}');
      });
    }
  }
  ```

## Caller.onRemoteStateChange<sup>10+</sup>

onRemoteStateChange(callback: OnRemoteStateChangeCallback): void;

注册协同场景下跨设备组件状态变化监听通知。

**系统能力**：SystemCapability.Ability.AbilityRuntime.AbilityCore

**参数：**

| 参数名 | 类型 | 必填 | 说明 |
| -------- | -------- | -------- | -------- |
| callback | [OnRemoteStateChangeCallback](#onremotestatechangecallback) | 是 | 返回onRemoteStateChange回调结果。 |

**错误码：**

| 错误码ID | 错误信息 |
| ------- | -------------------------------- |
| 16200001 | Caller released. The caller has been released. |

以上错误码详细介绍请参考[errcode-ability](../errorcodes/errorcode-ability.md)。

**示例：**

  ```ts
  import UIAbility from '@ohos.app.ability.UIAbility';
  import { Caller } from '@ohos.app.ability.UIAbility';
  import { BusinessError } from '@ohos.base';
  import window from '@ohos.window';

  let caller: Caller;
  let dstDeviceId: string;
  export default class MainAbility extends UIAbility {
      onWindowStageCreate(windowStage: window.WindowStage) {
          this.context.startAbilityByCall({
              bundleName: 'com.example.myservice',
              abilityName: 'MainUIAbility',
              deviceId: dstDeviceId
          }).then((obj) => {
              caller = obj;
              try {
                  caller.onRemoteStateChange((str) => {
                      console.log('Remote state changed ' + str);
                  });
              } catch (error) {
                  console.log('Caller.onRemoteStateChange catch error, error.code: ${JSON.stringify(error.code)}, error.message: ${JSON.stringify(error.message)}');
              }
          }).catch((err: BusinessError) => {
              console.log('Caller GetCaller error, error.code: ${JSON.stringify(err.code)}, error.message: ${JSON.stringify(err.message)}');
          })
      }
  }
  ```

## Caller.on

on(type: 'release', callback: OnReleaseCallback): void;

注册通用组件服务端Stub（桩）断开监听通知。

**系统能力**：SystemCapability.Ability.AbilityRuntime.AbilityCore

**参数：**

| 参数名 | 类型 | 必填 | 说明 |
| -------- | -------- | -------- | -------- |
| type | string | 是 | 监听releaseCall事件，固定为'release'。 |
| callback | [OnReleaseCallback](#onreleasecallback) | 是 | 返回onRelease回调结果。 |

**错误码：**

| 错误码ID | 错误信息 |
| ------- | -------------------------------- |
| 401 | If the input parameter is not valid parameter. |
| 16200001 | Caller released. The caller has been released. |

以上错误码详细介绍请参考[errcode-ability](../errorcodes/errorcode-ability.md)。

**示例：**

  ```ts
  import UIAbility from '@ohos.app.ability.UIAbility';
  import { Caller } from '@ohos.app.ability.UIAbility';
  import { BusinessError } from '@ohos.base';
  import window from '@ohos.window';

  let caller: Caller;
  export default class MainUIAbility extends UIAbility {
    onWindowStageCreate(windowStage: window.WindowStage) {
      this.context.startAbilityByCall({
        bundleName: 'com.example.myservice',
        abilityName: 'MainUIAbility',
        deviceId: ''
      }).then((obj) => {
          caller = obj;
          try {
            caller.on('release', (str) => {
                console.log(' Caller OnRelease CallBack is called ${str}');
            });
          } catch (error) {
            console.log('Caller.on catch error, error.code: ${error.code}, error.message: ${error.message}');
          }
      }).catch((err: BusinessError) => {
        console.log('Caller GetCaller error, error.code: ${err.code}, error.message: ${err.message}');
      });
    }
  }
  ```

## Caller.off

off(type: 'release', callback: OnReleaseCallback): void;

取消注册通用组件服务端Stub（桩）断开监听通知。预留能力，当前暂未支持。

**系统能力**：SystemCapability.Ability.AbilityRuntime.AbilityCore

**参数：**

| 参数名 | 类型 | 必填 | 说明 |
| -------- | -------- | -------- | -------- |
| type | string | 是 | 监听releaseCall事件，固定为'release'。 |
| callback | [OnReleaseCallback](#onreleasecallback) | 是 | 返回off回调结果。 |

**错误码：**

| 错误码ID | 错误信息 |
| ------- | -------------------------------- |
| 401 | If the input parameter is not valid parameter. |

**示例：**

  ```ts
  import UIAbility, { OnReleaseCallback } from '@ohos.app.ability.UIAbility';
  import { Caller } from '@ohos.app.ability.UIAbility';
  import { BusinessError } from '@ohos.base';
  import window from '@ohos.window';

  let caller: Caller;
  export default class MainUIAbility extends UIAbility {
    onWindowStageCreate(windowStage: window.WindowStage) {
      this.context.startAbilityByCall({
        bundleName: 'com.example.myservice',
        abilityName: 'MainUIAbility',
        deviceId: ''
      }).then((obj) => {
          caller = obj;
          try {
            let onReleaseCallBack: OnReleaseCallback = (str) => {
                console.log(' Caller OnRelease CallBack is called ${str}');
            };
            caller.on('release', onReleaseCallBack);
            caller.off('release', onReleaseCallBack);
          } catch (error) {
            console.log('Caller.on or Caller.off catch error, error.code: ${error.code}, error.message: ${error.message}');
          }
      }).catch((err: BusinessError) => {
        console.log('Caller GetCaller error, error.code: ${err.code}, error.message: ${err.message}');
      });
    }
  }
  ```

## Caller.off

off(type: 'release'): void;

取消注册通用组件服务端Stub（桩）断开监听通知。预留能力，当前暂未支持。

**系统能力**：SystemCapability.Ability.AbilityRuntime.AbilityCore

**参数：**

| 参数名 | 类型 | 必填 | 说明 |
| -------- | -------- | -------- | -------- |
| type | string | 是 | 监听releaseCall事件，固定为'release'。 |

**示例：**

  ```ts
  import UIAbility, { OnReleaseCallback } from '@ohos.app.ability.UIAbility';
  import { Caller } from '@ohos.app.ability.UIAbility';
  import { BusinessError } from '@ohos.base';
  import window from '@ohos.window';

  let caller: Caller;
  export default class MainUIAbility extends UIAbility {
    onWindowStageCreate(windowStage: window.WindowStage) {
      this.context.startAbilityByCall({
        bundleName: 'com.example.myservice',
        abilityName: 'MainUIAbility',
        deviceId: ''
      }).then((obj) => {
          caller = obj;
          try {
            let onReleaseCallBack: OnReleaseCallback = (str) => {
                console.log(' Caller OnRelease CallBack is called ${str}');
            };
            caller.on('release', onReleaseCallBack);
            caller.off('release');
          } catch (error) {
            console.error('Caller.on or Caller.off catch error, error.code: ${error.code}, error.message: ${error.message}');
          }
      }).catch((err: BusinessError) => {
        console.error('Caller GetCaller error, error.code: ${err.code}, error.message: ${err.message}');
      });
    }
  }
  ```

## Callee

通用组件服务端注册和解除客户端caller通知送信的callback接口。

## Callee.on

on(method: string, callback: CalleeCallback): void;

通用组件服务端注册消息通知callback。

**系统能力**：SystemCapability.Ability.AbilityRuntime.AbilityCore

**参数：**

| 参数名 | 类型 | 必填 | 说明 |
| -------- | -------- | -------- | -------- |
| method | string | 是 | 与客户端约定的通知消息字符串。 |
| callback | [CalleeCallback](#calleecallback) | 是 | 一个[rpc.MessageSequence](js-apis-rpc.md#messagesequence9)类型入参的js通知同步回调函数,&nbsp;回调函数至少要返回一个空的[rpc.Parcelable](js-apis-rpc.md#parcelable9)数据对象,&nbsp;其他视为函数执行错误。 |

**错误码：**

| 错误码ID | 错误信息 |
| ------- | -------------------------------- |
| 16200004 | Method registered. The method has registered. |
| 16000050 | Internal error. |

以上错误码详细介绍请参考[errcode-ability](../errorcodes/errorcode-ability.md)。

**示例：**

  ```ts
  import UIAbility, { CalleeCallback } from '@ohos.app.ability.UIAbility';
  import AbilityConstant from '@ohos.app.ability.AbilityConstant';
  import Want from '@ohos.app.ability.Want';
  import rpc from '@ohos.rpc';

  class MyMessageAble implements rpc.Parcelable {
      name: string
      str: string
      num: number = 1
      constructor(name: string, str: string) {
        this.name = name;
        this.str = str;
      }
      marshalling(messageSequence: rpc.MessageSequence) {
          messageSequence.writeInt(this.num);
          messageSequence.writeString(this.str);
          console.log('MyMessageAble marshalling num[${this.num}] str[${this.str}]');
          return true;
      }
      unmarshalling(messageSequence: rpc.MessageSequence) {
          this.num = messageSequence.readInt();
          this.str = messageSequence.readString();
          console.log('MyMessageAble unmarshalling num[${this.num}] str[${this.str}]');
          return true;
      }
  };
  let method = 'call_Function';
  function funcCallBack(pdata: rpc.MessageSequence) {
      console.log('Callee funcCallBack is called ${pdata}');
      let msg = new MyMessageAble('test', '');
      pdata.readParcelable(msg);
      return new MyMessageAble('test1', 'Callee test');
  }
  export default class MainUIAbility extends UIAbility {
    onCreate(want: Want, launchParam: AbilityConstant.LaunchParam) {
      console.log('Callee onCreate is called');
      try {
        this.callee.on(method, funcCallBack);
      } catch (error) {
        console.log('Callee.on catch error, error.code: ${error.code}, error.message: ${error.message}');
      }
    }
  }
  ```

## Callee.off

off(method: string): void;

解除通用组件服务端注册消息通知callback。

**系统能力**：SystemCapability.Ability.AbilityRuntime.AbilityCore

**参数：**

| 参数名 | 类型 | 必填 | 说明 |
| -------- | -------- | -------- | -------- |
| method | string | 是 | 已注册的通知事件字符串。 |

**错误码：**

| 错误码ID | 错误信息 |
| ------- | -------------------------------- |
| 16200005 | Method not registered. The method has not registered. |
| 16000050 | Internal error. |

以上错误码详细介绍请参考[errcode-ability](../errorcodes/errorcode-ability.md)。


**示例：**

  ```ts
  import UIAbility from '@ohos.app.ability.UIAbility';
  import AbilityConstant from '@ohos.app.ability.AbilityConstant';
  import Want from '@ohos.app.ability.Want';

  let method = 'call_Function';
  export default class MainUIAbility extends UIAbility {
    onCreate(want: Want, launchParam: AbilityConstant.LaunchParam) {
      console.log('Callee onCreate is called');
      try {
        this.callee.off(method);
      } catch (error) {
        console.log('Callee.off catch error, error.code: ${error.code}, error.message: ${error.message}');
      }
    }
  }
  ```

## OnReleaseCallback

(msg: string): void;

**系统能力**：SystemCapability.Ability.AbilityRuntime.AbilityCore

| 名称 | 可读 | 可写 | 类型 | 说明 |
| -------- | -------- | -------- | -------- | -------- |
| (msg: string) | 是 | 否 | function | 调用者注册的侦听器函数接口的原型。 |

## OnRemoteStateChangeCallback<sup>10+</sup>

(msg: string): void;

**系统能力**：SystemCapability.Ability.AbilityRuntime.AbilityCore

| 名称 | 可读 | 可写 | 类型 | 说明 |
| -------- | -------- | -------- | -------- | -------- |
| (msg: string) | 是 | 否 | function | 调用者注册的协同场景下组件状态变化监听函数接口的原型。 |

## CalleeCallback

(indata: rpc.MessageSequence): rpc.Parcelable;

**系统能力**：SystemCapability.Ability.AbilityRuntime.AbilityCore

| 名称 | 可读 | 可写 | 类型 | 说明 |
| -------- | -------- | -------- | -------- | -------- |
| (indata: [rpc.MessageSequence](js-apis-rpc.md#messagesequence9)) | 是 | 否 | [rpc.Parcelable](js-apis-rpc.md#parcelable9) | 被调用方注册的消息侦听器函数接口的原型。 |