ServiceExtensionContext

The ServiceExtensionContext module, inherited from ExtensionContext, provides context for ServiceExtensionAbilities.

You can use the APIs of this module to start, terminate, connect, and disconnect abilities.

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

import common from '@ohos.app.ability.common';

Usage

Before using the ServiceExtensionContext module, you must define a child class that inherits from ServiceExtensionAbility.

  import ServiceExtensionAbility from '@ohos.app.ability.ServiceExtensionAbility';

  let context = undefined;
  class MainAbility extends ServiceExtensionAbility {
    onCreate() {
      context = this.context; // Obtain a ServiceExtensionContext instance.
    }
  }

ServiceExtensionContext.startAbility

startAbility(want: Want, callback: AsyncCallback<void>): void;

Starts an ability. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.Ability.AbilityRuntime.Core

System API: This is a system API and cannot be called by third-party applications.

Parameters

Error codes

For details about the error codes, see Ability Error Codes.

Example

let want = {
  bundleName: 'com.example.myapp',
  abilityName: 'MyAbility'
};

try {
  this.context.startAbility(want, (error) => {
    if (error.code) {
      // Process service logic errors.
      console.log('startAbility failed, error.code: ' + JSON.stringify(error.code) +
        ' error.message: ' + JSON.stringify(error.message));
      return;
    }
    // Carry out normal service processing.
    console.log('startAbility succeed');
  });
} catch (paramError) {
  // Process input parameter errors.
  console.log('error.code: ' + JSON.stringify(paramError.code) +
    ' error.message: ' + JSON.stringify(paramError.message));
}

ServiceExtensionContext.startAbility

startAbility(want: Want, options?: StartOptions): Promise<void>;

Starts an ability. This API uses a promise to return the result.

System capability: SystemCapability.Ability.AbilityRuntime.Core

System API: This is a system API and cannot be called by third-party applications.

Parameters

Return value

Error codes

For details about the error codes, see Ability Error Codes.

Example

let want = {
  bundleName: 'com.example.myapp',
  abilityName: 'MyAbility'
};
let options = {
	windowMode: 0,
};

try {
  this.context.startAbility(want, options)
    .then((data) => {
      // Carry out normal service processing.
      console.log('startAbility succeed');
    })
    .catch((error) => {
      // Process service logic errors.
      console.log('startAbility failed, error.code: ' + JSON.stringify(error.code) +
        ' error.message: ' + JSON.stringify(error.message));
    });
} catch (paramError) {
  // Process input parameter errors.
  console.log('error.code: ' + JSON.stringify(paramError.code) +
    ' error.message: ' + JSON.stringify(paramError.message));
}

ServiceExtensionContext.startAbility

startAbility(want: Want, options: StartOptions, callback: AsyncCallback<void>): void

Starts an ability with the start options specified. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.Ability.AbilityRuntime.Core

System API: This is a system API and cannot be called by third-party applications.

Parameters

Error codes

For details about the error codes, see Ability Error Codes.

Example

let want = {
  deviceId: '',
  bundleName: 'com.extreme.test',
  abilityName: 'MainAbility'
};
let options = {
  windowMode: 0
};

try {
  this.context.startAbility(want, options, (error) => {
    if (error.code) {
      // Process service logic errors.
      console.log('startAbility failed, error.code: ' + JSON.stringify(error.code) +
        ' error.message: ' + JSON.stringify(error.message));
      return;
    }
    // Carry out normal service processing.
    console.log('startAbility succeed');
  });
} catch (paramError) {
  // Process input parameter errors.
  console.log('error.code: ' + JSON.stringify(paramError.code) +
    ' error.message: ' + JSON.stringify(paramError.message));
}

ServiceExtensionContext.startAbilityWithAccount

startAbilityWithAccount(want: Want, accountId: number, callback: AsyncCallback<void>): void;

Starts an ability with the account ID specified. This API uses an asynchronous callback to return the result.

Observe the following when using this API:

• If an application running in the background needs to call this API to start an ability, it must have the ohos.permission.START_ABILITIES_FROM_BACKGROUND permission.
• If visible of the target ability is false, the caller must have the ohos.permission.START_INVISIBLE_ABILITY permission.
• For details about the startup rules for the components in the stage model, see Component Startup Rules (Stage Model).

System capability: SystemCapability.Ability.AbilityRuntime.Core

System API: This is a system API and cannot be called by third-party applications.

Parameters

Error codes

For details about the error codes, see Ability Error Codes.

Example

let want = {
  deviceId: '',
  bundleName: 'com.extreme.test',
  abilityName: 'MainAbility'
};
let accountId = 100;

try {
  this.context.startAbilityWithAccount(want, accountId, (error) => {
    if (error.code) {
      // Process service logic errors.
      console.log('startAbilityWithAccount failed, error.code: ' + JSON.stringify(error.code) +
        ' error.message: ' + JSON.stringify(error.message));
      return;
    }
    // Carry out normal service processing.
    console.log('startAbilityWithAccount succeed');
  });
} catch (paramError) {
  // Process input parameter errors.
  console.log('error.code: ' + JSON.stringify(paramError.code) +
    ' error.message: ' + JSON.stringify(paramError.message));
}

ServiceExtensionContext.startAbilityWithAccount

startAbilityWithAccount(want: Want, accountId: number, options: StartOptions, callback: AsyncCallback<void>): void;

Starts an ability with the account ID and start options specified. This API uses an asynchronous callback to return the result.

Observe the following when using this API:

• If an application running in the background needs to call this API to start an ability, it must have the ohos.permission.START_ABILITIES_FROM_BACKGROUND permission.
• If visible of the target ability is false, the caller must have the ohos.permission.START_INVISIBLE_ABILITY permission.
• For details about the startup rules for the components in the stage model, see Component Startup Rules (Stage Model).

System capability: SystemCapability.Ability.AbilityRuntime.Core

System API: This is a system API and cannot be called by third-party applications.

Parameters

Error codes

For details about the error codes, see Ability Error Codes.

Example

let want = {
  deviceId: '',
  bundleName: 'com.extreme.test',
  abilityName: 'MainAbility'
};
let accountId = 100;
let options = {
  windowMode: 0
};

try {
  this.context.startAbilityWithAccount(want, accountId, options, (error) => {
    if (error.code) {
      // Process service logic errors.
      console.log('startAbilityWithAccount failed, error.code: ' + JSON.stringify(error.code) +
        ' error.message: ' + JSON.stringify(error.message));
      return;
    }
    // Carry out normal service processing.
    console.log('startAbilityWithAccount succeed');
  });
} catch (paramError) {
  // Process input parameter errors.
  console.log('error.code: ' + JSON.stringify(paramError.code) +
    ' error.message: ' + JSON.stringify(paramError.message));
}

ServiceExtensionContext.startAbilityWithAccount

startAbilityWithAccount(want: Want, accountId: number, options?: StartOptions): Promise<void>;

Starts an ability with the account ID specified. This API uses a promise to return the result.

Observe the following when using this API:

• If an application running in the background needs to call this API to start an ability, it must have the ohos.permission.START_ABILITIES_FROM_BACKGROUND permission.
• If visible of the target ability is false, the caller must have the ohos.permission.START_INVISIBLE_ABILITY permission.
• For details about the startup rules for the components in the stage model, see Component Startup Rules (Stage Model).

System capability: SystemCapability.Ability.AbilityRuntime.Core

System API: This is a system API and cannot be called by third-party applications.

Parameters

Return value

Error codes

For details about the error codes, see Ability Error Codes.

Example

let want = {
  deviceId: '',
  bundleName: 'com.extreme.test',
  abilityName: 'MainAbility'
};
let accountId = 100;
let options = {
  windowMode: 0
};

try {
  this.context.startAbilityWithAccount(want, accountId, options)
    .then((data) => {
      // Carry out normal service processing.
      console.log('startAbilityWithAccount succeed');
    })
    .catch((error) => {
      // Process service logic errors.
      console.log('startAbilityWithAccount failed, error.code: ' + JSON.stringify(error.code) +
        ' error.message: ' + JSON.stringify(error.message));
    });
} catch (paramError) {
  // Process input parameter errors.
  console.log('error.code: ' + JSON.stringify(paramError.code) +
    ' error.message: ' + JSON.stringify(paramError.message));
}

ServiceExtensionContext.startServiceExtensionAbility

startServiceExtensionAbility(want: Want, callback: AsyncCallback<void>): void;

Starts a new ServiceExtensionAbility. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.Ability.AbilityRuntime.Core

System API: This is a system API and cannot be called by third-party applications.

Parameters

Error codes

For details about the error codes, see Ability Error Codes.

Example

let want = {
  deviceId: '',
  bundleName: 'com.extreme.test',
  abilityName: 'MainAbility'
};

try {
  this.context.startServiceExtensionAbility(want, (error) => {
    if (error.code) {
      // Process service logic errors.
      console.log('startServiceExtensionAbility failed, error.code: ' + JSON.stringify(error.code) +
        ' error.message: ' + JSON.stringify(error.message));
      return;
    }
    // Carry out normal service processing.
    console.log('startServiceExtensionAbility succeed');
  });
} catch (paramError) {
  // Process input parameter errors.
  console.log('error.code: ' + JSON.stringify(paramError.code) +
    ' error.message: ' + JSON.stringify(paramError.message));
}

ServiceExtensionContext.startServiceExtensionAbility

startServiceExtensionAbility(want: Want): Promise<void>;

Starts a new ServiceExtensionAbility. This API uses a promise to return the result.

System capability: SystemCapability.Ability.AbilityRuntime.Core

System API: This is a system API and cannot be called by third-party applications.

Parameters

Return value

Error codes

For details about the error codes, see Ability Error Codes.

Example

let want = {
  deviceId: '',
  bundleName: 'com.extreme.test',
  abilityName: 'MainAbility'
};

try {
  this.context.startServiceExtensionAbility(want)
    .then((data) => {
      // Carry out normal service processing.
      console.log('startServiceExtensionAbility succeed');
    })
    .catch((error) => {
      // Process service logic errors.
      console.log('startServiceExtensionAbility failed, error.code: ' + JSON.stringify(error.code) +
        ' error.message: ' + JSON.stringify(error.message));
    });
} catch (paramError) {
  // Process input parameter errors.
  console.log('error.code: ' + JSON.stringify(paramError.code) +
    ' error.message: ' + JSON.stringify(paramError.message));
}

ServiceExtensionContext.startServiceExtensionAbilityWithAccount

startServiceExtensionAbilityWithAccount(want: Want, accountId: number, callback: AsyncCallback<void>): void;

Starts a new ServiceExtensionAbility with the account ID specified. This API uses an asynchronous callback to return the result.

Required permissions: ohos.permission.INTERACT_ACROSS_LOCAL_ACCOUNTS

System capability: SystemCapability.Ability.AbilityRuntime.Core

System API: This is a system API and cannot be called by third-party applications.

Parameters

Error codes

For details about the error codes, see Ability Error Codes.

Example

let want = {
  deviceId: '',
  bundleName: 'com.extreme.test',
  abilityName: 'MainAbility'
};
let accountId = 100;

try {
  this.context.startServiceExtensionAbilityWithAccount(want, accountId, (error) => {
    if (error.code) {
      // Process service logic errors.
      console.log('startServiceExtensionAbilityWithAccount failed, error.code: ' + JSON.stringify(error.code) +
        ' error.message: ' + JSON.stringify(error.message));
      return;
    }
    // Carry out normal service processing.
    console.log('startServiceExtensionAbilityWithAccount succeed');
  });
} catch (paramError) {
  // Process input parameter errors.
  console.log('error.code: ' + JSON.stringify(paramError.code) +
    ' error.message: ' + JSON.stringify(paramError.message));
}

ServiceExtensionContext.startServiceExtensionAbilityWithAccount

startServiceExtensionAbilityWithAccount(want: Want, accountId: number): Promise<void>;

Starts a new ServiceExtensionAbility with the account ID specified. This API uses a promise to return the result.

Required permissions: ohos.permission.INTERACT_ACROSS_LOCAL_ACCOUNTS

System capability: SystemCapability.Ability.AbilityRuntime.Core

System API: This is a system API and cannot be called by third-party applications.

Parameters

Return value

Error codes

For details about the error codes, see Ability Error Codes.

Example

let want = {
  deviceId: '',
  bundleName: 'com.extreme.test',
  abilityName: 'MainAbility'
};
let accountId = 100;

try {
  this.context.startServiceExtensionAbilityWithAccount(want, accountId)
    .then((data) => {
      // Carry out normal service processing.
      console.log('startServiceExtensionAbilityWithAccount succeed');
    })
    .catch((error) => {
      // Process service logic errors.
      console.log('startServiceExtensionAbilityWithAccount failed, error.code: ' + JSON.stringify(error.code) +
        ' error.message: ' + JSON.stringify(error.message));
    });
} catch (paramError) {
  // Process input parameter errors.
  console.log('error.code: ' + JSON.stringify(paramError.code) +
    ' error.message: ' + JSON.stringify(paramError.message));
}

ServiceExtensionContext.stopServiceExtensionAbility

stopServiceExtensionAbility(want: Want, callback: AsyncCallback<void>): void;

Stops a ServiceExtensionAbility in the same application. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.Ability.AbilityRuntime.Core

System API: This is a system API and cannot be called by third-party applications.

Parameters

Error codes

For details about the error codes, see Ability Error Codes.

Example

let want = {
  deviceId: '',
  bundleName: 'com.extreme.test',
  abilityName: 'MainAbility'
};

try {
  this.context.stopServiceExtensionAbility(want, (error) => {
    if (error.code) {
      // Process service logic errors.
      console.log('stopServiceExtensionAbility failed, error.code: ' + JSON.stringify(error.code) +
        ' error.message: ' + JSON.stringify(error.message));
      return;
    }
    // Carry out normal service processing.
    console.log('stopServiceExtensionAbility succeed');
  });
} catch (paramError) {
  // Process input parameter errors.
  console.log('error.code: ' + JSON.stringify(paramError.code) +
    ' error.message: ' + JSON.stringify(paramError.message));
}

ServiceExtensionContext.stopServiceExtensionAbility

stopServiceExtensionAbility(want: Want): Promise<void>;

Stops a ServiceExtensionAbility in the same application. This API uses a promise to return the result.

System capability: SystemCapability.Ability.AbilityRuntime.Core

System API: This is a system API and cannot be called by third-party applications.

Parameters

Return value

Error codes

For details about the error codes, see Ability Error Codes.

Example

let want = {
  deviceId: '',
  bundleName: 'com.extreme.test',
  abilityName: 'MainAbility'
};

try {
  this.context.stopServiceExtensionAbility(want)
    .then((data) => {
      // Carry out normal service processing.
      console.log('stopServiceExtensionAbility succeed');
    })
    .catch((error) => {
      // Process service logic errors.
      console.log('stopServiceExtensionAbility failed, error.code: ' + JSON.stringify(error.code) +
        ' error.message: ' + JSON.stringify(error.message));
    });
} catch (paramError) {
  // Process input parameter errors.
  console.log('error.code: ' + JSON.stringify(paramError.code) +
    ' error.message: ' + JSON.stringify(paramError.message));
}

ServiceExtensionContext.stopServiceExtensionAbilityWithAccount

stopServiceExtensionAbilityWithAccount(want: Want, accountId: number, callback: AsyncCallback<void>): void;

Stops a ServiceExtensionAbility in the same application with the account ID specified. This API uses an asynchronous callback to return the result.

Required permissions: ohos.permission.INTERACT_ACROSS_LOCAL_ACCOUNTS

System capability: SystemCapability.Ability.AbilityRuntime.Core

System API: This is a system API and cannot be called by third-party applications.

Parameters

Error codes

For details about the error codes, see Ability Error Codes.

Example

let want = {
  deviceId: '',
  bundleName: 'com.extreme.test',
  abilityName: 'MainAbility'
};
let accountId = 100;

try {
  this.context.stopServiceExtensionAbilityWithAccount(want, accountId, (error) => {
    if (error.code) {
      // Process service logic errors.
      console.log('stopServiceExtensionAbilityWithAccount failed, error.code: ' + JSON.stringify(error.code) +
        ' error.message: ' + JSON.stringify(error.message));
      return;
    }
    // Carry out normal service processing.
    console.log('stopServiceExtensionAbilityWithAccount succeed');
  });
} catch (paramError) {
  // Process input parameter errors.
  console.log('error.code: ' + JSON.stringify(paramError.code) +
    ' error.message: ' + JSON.stringify(paramError.message));
}

ServiceExtensionContext.stopServiceExtensionAbilityWithAccount

stopServiceExtensionAbilityWithAccount(want: Want, accountId: number): Promise<void>;

Stops a ServiceExtensionAbility in the same application with the account ID specified. This API uses a promise to return the result.

Required permissions: ohos.permission.INTERACT_ACROSS_LOCAL_ACCOUNTS

System capability: SystemCapability.Ability.AbilityRuntime.Core

System API: This is a system API and cannot be called by third-party applications.

Parameters

Return value

Error codes

For details about the error codes, see Ability Error Codes.

Example

let want = {
  deviceId: '',
  bundleName: 'com.extreme.test',
  abilityName: 'MainAbility'
};
let accountId = 100;

try {
  this.context.stopServiceExtensionAbilityWithAccount(want, accountId)
    .then((data) => {
      // Carry out normal service processing.
      console.log('stopServiceExtensionAbilityWithAccount succeed');
    })
    .catch((error) => {
      // Process service logic errors.
      console.log('stopServiceExtensionAbilityWithAccount failed, error.code: ' + JSON.stringify(error.code) +
        ' error.message: ' + JSON.stringify(error.message));
    });
} catch (paramError) {
  // Process input parameter errors.
  console.log('error.code: ' + JSON.stringify(paramError.code) +
    ' error.message: ' + JSON.stringify(paramError.message));
}

ServiceExtensionContext.terminateSelf

terminateSelf(callback: AsyncCallback<void>): void;

Terminates this ability. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.Ability.AbilityRuntime.Core

System API: This is a system API and cannot be called by third-party applications.

Parameters

Error codes

For details about the error codes, see Ability Error Codes.

Example

this.context.terminateSelf((error) => {
  if (error.code) {
    // Process service logic errors.
    console.log('terminateSelf failed, error.code: ' + JSON.stringify(error.code) +
      ' error.message: ' + JSON.stringify(error.message));
    return;
  }
  // Carry out normal service processing.
  console.log('terminateSelf succeed');
});

ServiceExtensionContext.terminateSelf

terminateSelf(): Promise<void>;

Terminates this ability. This API uses a promise to return the result.

System capability: SystemCapability.Ability.AbilityRuntime.Core

System API: This is a system API and cannot be called by third-party applications.

Return value

Error codes

For details about the error codes, see Ability Error Codes.

Example

this.context.terminateSelf().then((data) => {
  // Carry out normal service processing.
  console.log('terminateSelf succeed');
}).catch((error) => {
  // Process service logic errors.
  console.log('terminateSelf failed, error.code: ' + JSON.stringify(error.code) +
    ' error.message: ' + JSON.stringify(error.message));
});

ServiceExtensionContext.connectServiceExtensionAbility

connectServiceExtensionAbility(want: Want, options: ConnectOptions): number;

Connects this ability to a ServiceExtensionAbility.

System capability: SystemCapability.Ability.AbilityRuntime.Core

System API: This is a system API and cannot be called by third-party applications.

Parameters

Return value

Error codes

For details about the error codes, see Ability Error Codes.

Example

let want = {
  bundleName: 'com.example.myapp',
  abilityName: 'MyAbility'
};
let options = {
  onConnect(elementName, remote) { console.log('----------- onConnect -----------') },
  onDisconnect(elementName) { console.log('----------- onDisconnect -----------') },
  onFailed(code) { console.log('----------- onFailed -----------') }
};

let connection = null;
try {
  connection = this.context.connectServiceExtensionAbility(want, options);
} catch (paramError) {
  // Process input parameter errors.
  console.log('error.code: ' + JSON.stringify(paramError.code) +
    ' error.message: ' + JSON.stringify(paramError.message));
}

ServiceExtensionContext.connectServiceExtensionAbilityWithAccount

connectServiceExtensionAbilityWithAccount(want: Want, accountId: number, options: ConnectOptions): number;

Uses the AbilityInfo.AbilityType.SERVICE template and account ID to connect this ability to another ability.

System capability: SystemCapability.Ability.AbilityRuntime.Core

System API: This is a system API and cannot be called by third-party applications.

Parameters

Return value

Error codes

For details about the error codes, see Ability Error Codes.

Example

let want = {
  deviceId: '',
  bundleName: 'com.extreme.test',
  abilityName: 'MainAbility'
};
let accountId = 100;
let options = {
  onConnect(elementName, remote) { console.log('----------- onConnect -----------') },
  onDisconnect(elementName) { console.log('----------- onDisconnect -----------') },
  onFailed(code) { console.log('----------- onFailed -----------') }
}

let connection = null;
try {
  connection = this.context.connectServiceExtensionAbilityWithAccount(want, accountId, options);
} catch (paramError) {
  // Process input parameter errors.
  console.log('error.code: ' + JSON.stringify(paramError.code) +
    ' error.message: ' + JSON.stringify(paramError.message));
}

ServiceExtensionContext.disconnectServiceExtensionAbility

disconnectServiceExtensionAbility(connection: number, callback:AsyncCallback<void>): void;

Disconnects this ability from the ServiceExtensionAbility. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.Ability.AbilityRuntime.Core

System API: This is a system API and cannot be called by third-party applications.

Parameters

Error codes

For details about the error codes, see Ability Error Codes.

Example

// connection is the return value of connectServiceExtensionAbility.
let connection = 1;

try {
  this.context.disconnectServiceExtensionAbility(connection, (error) => {
    if (error.code) {
      // Process service logic errors.
      console.log('disconnectServiceExtensionAbility failed, error.code: ' + JSON.stringify(error.code) +
        ' error.message: ' + JSON.stringify(error.message));
      return;
    }
    // Carry out normal service processing.
    console.log('disconnectServiceExtensionAbility succeed');
  });
} catch (paramError) {
  // Process input parameter errors.
  console.log('error.code: ' + JSON.stringify(paramError.code) +
    ' error.message: ' + JSON.stringify(paramError.message));
}

ServiceExtensionContext.disconnectServiceExtensionAbility

disconnectServiceExtensionAbility(connection: number): Promise<void>;

Disconnects this ability from the ServiceExtensionAbility. This API uses a promise to return the result.

System capability: SystemCapability.Ability.AbilityRuntime.Core

System API: This is a system API and cannot be called by third-party applications.

Parameters

Return value

Error codes

For details about the error codes, see Ability Error Codes.

Example

// connection is the return value of connectServiceExtensionAbility.
let connection = 1;

try {
  this.context.disconnectServiceExtensionAbility(connection)
    .then((data) => {
      // Carry out normal service processing.
      console.log('disconnectServiceExtensionAbility succeed');
    })
    .catch((error) => {
      // Process service logic errors.
      console.log('disconnectServiceExtensionAbility failed, error.code: ' + JSON.stringify(error.code) +
        ' error.message: ' + JSON.stringify(error.message));
    });
} catch (paramError) {
  // Process input parameter errors.
  console.log('error.code: ' + JSON.stringify(paramError.code) +
    ' error.message: ' + JSON.stringify(paramError.message));
}

ServiceExtensionContext.startAbilityByCall

startAbilityByCall(want: Want): Promise<Caller>;

Starts an ability in the foreground or background and obtains the caller object for communicating with the ability.

Observe the following when using this API:

• If an application running in the background needs to call this API to start an ability, it must have the ohos.permission.START_ABILITIES_FROM_BACKGROUND permission.
• If visible of the target ability is false, the caller must have the ohos.permission.START_INVISIBLE_ABILITY permission.
• For details about the startup rules for the components in the stage model, see Component Startup Rules (Stage Model).

System capability: SystemCapability.Ability.AbilityRuntime.Core

System API: This is a system API and cannot be called by third-party applications.

Parameters

Return value

Error codes

For details about the error codes, see Ability Error Codes.

Example

Start an ability in the background.

let caller = undefined;

// Start an ability in the background by not passing parameters.
let wantBackground = {
    bundleName: 'com.example.myservice',
    moduleName: 'entry',
    abilityName: 'MainAbility',
    deviceId: ''
};

try {
  this.context.startAbilityByCall(wantBackground)
    .then((obj) => {
      // Carry out normal service processing.
      caller = obj;
      console.log('startAbilityByCall succeed');
    }).catch((error) => {
      // Process service logic errors.
      console.log('startAbilityByCall failed, error.code: ' + JSON.stringify(error.code) +
        ' error.message: ' + JSON.stringify(error.message));
    });
} catch (paramError) {
  // Process input parameter errors.
  console.log('error.code: ' + JSON.stringify(paramError.code) +
    ' error.message: ' + JSON.stringify(paramError.message));
}

Start an ability in the foreground.

let caller = undefined;

// Start an ability in the foreground with 'ohos.aafwk.param.callAbilityToForeground' in parameters set to true.
let wantForeground = {
    bundleName: 'com.example.myservice',
    moduleName: 'entry',
    abilityName: 'MainAbility',
    deviceId: '',
    parameters: {
      'ohos.aafwk.param.callAbilityToForeground': true
    }
};

try {
  this.context.startAbilityByCall(wantForeground)
    .then((obj) => {
      // Carry out normal service processing.
      caller = obj;
      console.log('startAbilityByCall succeed');
    }).catch((error) => {
      // Process service logic errors.
      console.log('startAbilityByCall failed, error.code: ' + JSON.stringify(error.code) +
        ' error.message: ' + JSON.stringify(error.message));
    });
} catch (paramError) {
  // Process input parameter errors.
  console.log('error.code: ' + JSON.stringify(paramError.code) +
    ' error.message: ' + JSON.stringify(paramError.message));
}