FormExtensionContext (System API)

The FormExtensionContext module, inherited from ExtensionContext, provides the context environment for the FormExtensionAbility.

You can use the APIs of this module to start a FormExtensionAbility.

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. The APIs provided by this module are system APIs.

Modules to Import

import { common } from '@kit.AbilityKit';

FormExtensionContext.startAbility

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

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

System API: This is a system API.

System capability: SystemCapability.Ability.Form

Error codes

For details about the error codes, see Universal Error Codes and Form Error Codes.

ID	Error Message
202	The application is not a system application.
401	Parameter error. Possible causes: 1.Mandatory parameters are left unspecified; 2.Incorrect parameter types; 3.Parameter verification failed.
16500050	IPC connection error.
16500100	Failed to obtain the configuration information.
16501000	An internal functional error occurred.

Parameters

Name	Type	Mandatory	Description
want	Want	Yes	Information about the ability to start, such as the bundle name, ability name, and custom parameters.
callback	AsyncCallback<void>	Yes	Callback used to return the result. If the ability is started, err is undefined; otherwise, err is an error object.

Example

import { FormExtensionAbility } from '@kit.FormKit';
import { Want } from '@kit.AbilityKit';
import { BusinessError } from '@kit.BasicServicesKit';

export default class MyFormExtensionAbility extends FormExtensionAbility {
  onFormEvent(formId: string, message: string) {
    // Call startAbility() when the message event is triggered.
    console.log(`FormExtensionAbility onFormEvent, formId: ${formId}, message:${message}`);
    let want: Want = {
      deviceId: '',
      bundleName: 'com.example.formstartability',
      abilityName: 'EntryAbility',
      parameters: {
        'message': message
      }
    };
    this.context.startAbility(want, (error: BusinessError) => {
      if (error) {
        console.error(`FormExtensionContext startAbility, error:${JSON.stringify(error)}`);
      } else {
        console.log('FormExtensionContext startAbility success');
      }
    });
  }
};

FormExtensionContext.startAbility

startAbility(want: Want): Promise<void>

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

System API: This is a system API.

System capability: SystemCapability.Ability.Form

Parameters

Name	Type	Mandatory	Description
want	Want	Yes	Information about the ability to start, such as the bundle name, ability name, and custom parameters.

Return value

Type	Description
Promise<void>	Promise that returns no value.

Error codes

For details about the error codes, see Universal Error Codes and Form Error Codes.

ID	Error Message
202	The application is not a system application.
401	Parameter error. Possible causes: 1.Mandatory parameters are left unspecified; 2.Incorrect parameter types; 3.Parameter verification failed.
16500050	IPC connection error.
16500100	Failed to obtain the configuration information.
16501000	An internal functional error occurred.

Example

import { FormExtensionAbility } from '@kit.FormKit';
import { Want } from '@kit.AbilityKit';
import { BusinessError } from '@kit.BasicServicesKit';

export default class MyFormExtensionAbility extends FormExtensionAbility {
  onFormEvent(formId: string, message: string) {
    // Call startAbility() when the message event is triggered.
    console.log(`FormExtensionAbility onFormEvent, formId:${formId}, message:${message}`);
    let want: Want = {
      deviceId: '',
      bundleName: 'com.example.formstartability',
      abilityName: 'EntryAbility',
      parameters: {
        'message': message
      }
    };
    this.context.startAbility(want).then(() => {
      console.info('StartAbility Success');
    }).catch((error: BusinessError) => {
      console.error(`StartAbility failed, error.code: ${error.code}, error.message: ${error.message}`);
    });
  }
};

FormExtensionContext.connectServiceExtensionAbility¹⁰⁺

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

Connects this ability to a ServiceExtensionAbility.

System capability: SystemCapability.Ability.Form

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

Parameters

Name	Type	Mandatory	Description
want	Want	Yes	Want information about the target ability, such as the ability name and bundle name.
options	ConnectOptions	Yes	Callback used to return the information indicating that the connection is successful, interrupted, or failed.

Return value

Type	Description
number	Returns a connect ID, which will be used for the disconnection.

Error codes

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

ID	Error Message
201	Permissions denied.
401	Parameter error. Possible causes: 1.Mandatory parameters are left unspecified; 2.Incorrect parameter types; 3.Parameter verification failed.
16000001	The specified ability does not exist.
16000002	Incorrect ability type.
16000004	Can not start invisible component.
16000005	The specified process does not have the permission.
16000006	Cross-user operations are not allowed.
16000008	The crowdtesting application expires.
16000053	The ability is not on the top of the UI.
16000055	Installation-free timed out.
16000011	The context does not exist.
16000050	Internal error.

Example

import { rpc } from '@kit.IPCKit';
import { FormExtensionAbility } from '@kit.FormKit';
import { common, Want } from '@kit.AbilityKit';
import { BusinessError } from '@kit.BasicServicesKit';

let commRemote: rpc.IRemoteObject|null = null;

export default class MyFormExtensionAbility extends FormExtensionAbility {
  onFormEvent(formId: string, message: string) {
    // Call connectServiceExtensionAbility() when the message event is triggered.
    console.log(`FormExtensionAbility onFormEvent, formId:${formId}, message:${message}`);
    let want: Want = {
      deviceId: '',
      bundleName: 'com.example.formstartability',
      abilityName: 'EntryAbility',
      parameters: {
        'message': message
      }
    };
    let options: common.ConnectOptions = {
      onConnect(elementName, remote) {
        commRemote = remote; // remote is used to communicate with the ServiceExtensionAbility.
        console.log('----------- onConnect -----------');
      },
      onDisconnect(elementName) {
        console.log('----------- onDisconnect -----------')
      },
      onFailed(code) {
        console.error('----------- onFailed -----------')
      }
    };

    let connection: number|null = null;
    try {
      connection = this.context.connectServiceExtensionAbility(want, options);
    } catch (paramError) {
      // Process input parameter errors.
      console.error(`error.code: ${(paramError as BusinessError).code}, error.message: ${(paramError as BusinessError).message}`);
    }
  }
};

FormExtensionContext.disconnectServiceExtensionAbility¹⁰⁺

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

Disconnects this ability from a ServiceExtensionAbility and after the successful disconnection, sets the remote object returned upon the connection to void. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.Ability.Form

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

Parameters

Name	Type	Mandatory	Description
connection	number	Yes	Number returned after connectServiceExtensionAbility is called.
callback	AsyncCallback<void>	Yes	Callback used to return the result. If the ability is disconnected, err is undefined; otherwise, err is an error object.

Error codes

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

ID	Error Message
401	Parameter error. Possible causes: 1.Mandatory parameters are left unspecified; 2.Incorrect parameter types; 3.Parameter verification failed.
16000011	The context does not exist.
16000050	Internal error.

Example

import { FormExtensionAbility } from '@kit.FormKit';
import { rpc } from '@kit.IPCKit';
import { BusinessError } from '@kit.BasicServicesKit';

// commRemote is the remote object returned in the onConnect() callback. The value null is meaningless and is only an example.
let commRemote: rpc.IRemoteObject|null = null;
export default class MyFormExtensionAbility extends FormExtensionAbility {
  onFormEvent(formId: string, message: string) {
    // In actual use, connection is the return value of connectServiceExtensionAbility(). The value 1 is meaningless and is only an example.
    let connection: number = 1;

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

FormExtensionContext.disconnectServiceExtensionAbility¹⁰⁺

disconnectServiceExtensionAbility(connection: number): Promise<void>

Disconnects this ability from a ServiceExtensionAbility and after the successful disconnection, sets the remote object returned upon the connection to void. This API uses a promise to return the result.

System capability: SystemCapability.Ability.Form

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

Parameters

Name	Type	Mandatory	Description
connection	number	Yes	Number returned after connectServiceExtensionAbility is called.

Return value

Type	Description
Promise<void>	Promise that returns no value.

Error codes

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

ID	Error Message
401	Parameter error. Possible causes: 1.Mandatory parameters are left unspecified; 2.Incorrect parameter types; 3.Parameter verification failed.
16000011	The context does not exist.
16000050	Internal error.

Example

import { FormExtensionAbility } from '@kit.FormKit';
import { rpc } from '@kit.IPCKit';
import { BusinessError } from '@kit.BasicServicesKit';

// commRemote is the remote object returned in the onConnect() callback. The value null is meaningless and is only an example.
let commRemote: rpc.IRemoteObject|null = null;
export default class MyFormExtensionAbility extends FormExtensionAbility {
  onFormEvent(formId: string, message: string) {
    // In actual use, connection is the return value of connectServiceExtensionAbility(). The value 1 is meaningless and is only an example.
    let connection: number = 1;

    try {
      this.context.disconnectServiceExtensionAbility(connection)
        .then(() => {
          commRemote = null;
          // Carry out normal service processing.
          console.log('disconnectServiceExtensionAbility succeed');
        })
        .catch((error: BusinessError) => {
          commRemote = null;
          // Process service logic errors.
          console.error(`disconnectServiceExtensionAbility failed, error.code: ${error.code}, error.message: ${error.message}`);
        });
    } catch (paramError) {
      commRemote = null;
      // Process input parameter errors.
      console.error(`error.code: ${(paramError as BusinessError).code}, error.message: ${(paramError as BusinessError).message}`);
    }
  }
};