@ohos.nfc.cardEmulation (Standard NFC Card Emulation)

The cardEmulation module implements Near-Field Communication (NFC) card emulation. You can use the APIs provided by this module to determine the card emulation type supported and implement Host Card Emulation (HCE). HCE provides card emulation that does not depend on a secure element. It allows an application to emulate a card and communicate with an NFC card reader through the NFC service.

NOTE

The initial APIs of this module are supported since API version 6. Newly added APIs will be marked with a superscript to indicate their earliest API version.

HCE and AID Declaration

Before developing an application related to HCE, you must declare NFC-related attributes in the module.json5 file.

{
  "module": {
    // Other declared attributes.
    "abilities": [
      {
        // Other declared attributes.
        "skills": [
          {
            "actions": [
              "ohos.nfc.cardemulation.action.HOST_APDU_SERVICE"
            ]
          }
        ],
        "metadata": [
          {
            "name": "payment-aid",
            "value": "your payment aid"
          },
          {
            "name": "other-aid",
            "value": "your other aid"
          }
        ]
      }
    ],
    "requestPermissions": [
      {
        "name": "ohos.permission.NFC_CARD_EMULATION",
        // should add variable card_emulation_reason in string.json
        "reason": "$string:card_emulation_reason",
      }
    ]
  }
}

NOTE

• The actions field must contain ohos.nfc.cardemulation.action.HOST_APDU_SERVICE and cannot be changed.
• The name fields under metadata must be payment-aid or other-aid when application IDs (AIDs) are declared. Incorrect setting will cause a parsing failure.
• The name field of requestPermissions must be ohos.permission.NFC_CARD_EMULATION and cannot be changed.

Modules to Import

import cardEmulation from '@ohos.nfc.cardEmulation';

FeatureType^(deprecated)

Enumerates the NFC card emulation types.

NOTE This API is supported since API version 6 and deprecated since API version 9. Use hasHceCapability instead.

System capability: SystemCapability.Communication.NFC.CardEmulation

CardType⁹⁺

Enumerates the types of services used by the card emulation application.

System capability: SystemCapability.Communication.NFC.CardEmulation

isSupported^(deprecated)

isSupported(feature: number): boolean

Checks whether a certain type of card emulation is supported.

NOTE This API is supported since API version 6 and deprecated since API version 9. Use hasHceCapability instead.

System capability: SystemCapability.Communication.NFC.CardEmulation

Parameters

Return value

hasHceCapability⁹⁺

hasHceCapability(): boolean

Checks whether the device supports HCE.

System capability: SystemCapability.Communication.NFC.CardEmulation

Required permissions: ohos.permission.NFC_CARD_EMULATION

Ability API set: Since API version 12, this API can be used in abilities.

Return value

Example

import cardEmulation from '@ohos.nfc.cardEmulation';

let isHceSupported = cardEmulation.isSupported(cardEmulation.FeatureType.HCE);
if (!isHceSupported) {
    console.log('this device is not supported for HCE, ignore it.');
}

let hasHceCap = cardEmulation.hasHceCapability();
if (!hasHceCap) {
    console.log('this device hasHceCapability false, ignore it.');
}

isDefaultService⁹⁺

isDefaultService(elementName: ElementName, type: CardType): boolean

Checks whether an application is the default application of the specified service type.

System capability: SystemCapability.Communication.NFC.CardEmulation

Required permissions: ohos.permission.NFC_CARD_EMULATION

Ability API set: Since API version 12, this API can be used in abilities.

Parameters

Return value

Example

import cardEmulation from '@ohos.nfc.cardEmulation';
import bundleManager from '@ohos.bundle.bundleManager';

let elementName : bundleManager.ElementName;

// Initialize elementName here. bundleName and abilityName are required.

let isDefaultService = cardEmulation.isDefaultService(elementName, cardEmulation.CardType.PAYMENT);
// Do something according to the isDefaultService value.

HceService⁸⁺

Provides APIs for implementing HCE, including receiving Application Protocol Data Units (APDUs) from the peer card reader and sending a response. Before using HCE-related APIs, check whether the device supports HCE.

startHCE^(deprecated)

startHCE(aidList: string[]): boolean

Starts HCE, including enabling this application to run in the foreground preferentially and dynamically registering the AID list. This API is used only for declaration and cannot be used currently.

NOTE This API is supported since API version 8 and deprecated since API version 9. Use start instead.

Required permissions: ohos.permission.NFC_CARD_EMULATION

System capability: SystemCapability.Communication.NFC.CardEmulation

Parameters

Return value

start⁹⁺

start(elementName: ElementName, aidList: string[]): void

Starts HCE, including enabling this application to run in the foreground preferentially and dynamically registering the AID list. This API is used only for declaration and cannot be used currently.

Required permissions: ohos.permission.NFC_CARD_EMULATION

System capability: SystemCapability.Communication.NFC.CardEmulation

Ability API set: Since API version 12, this API can be used in abilities.

Parameters

Error codes

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

stopHCE^(deprecated)

stopHCE(): boolean

Stops HCE, including exiting the current application from the foreground, releasing the dynamically registered AID list, and canceling the subscription of hceCmd.

NOTE This API is supported since API version 8 and deprecated since API version 9. Use stop instead.

Required permissions: ohos.permission.NFC_CARD_EMULATION

System capability: SystemCapability.Communication.NFC.CardEmulation

Return value

Example

For details, see the example of on.

stop⁹⁺

stop(elementName: ElementName): void

Stops HCE, including canceling the subscription of APDU data, exiting this application from the foreground, and releasing the dynamically registered AID list. The application needs to call this API in onDestroy of the HCE page.

Required permissions: ohos.permission.NFC_CARD_EMULATION

System capability: SystemCapability.Communication.NFC.CardEmulation

Ability API set: Since API version 12, this API can be used in abilities.

Parameters

Error codes

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

on⁸⁺

on(type: 'hceCmd', callback: AsyncCallback<number[]>): void

Registers a callback to receive APDUs from the peer card reader. The application needs to call this API in onCreate() of the HCE page.

Required permissions: ohos.permission.NFC_CARD_EMULATION

System capability: SystemCapability.Communication.NFC.CardEmulation

Ability API set: Since API version 12, this API can be used in abilities.

Parameters

Example

import UIAbility from '@ohos.app.ability.UIAbility';
import hilog from '@ohos.hilog';
import cardEmulation from '@ohos.nfc.cardEmulation';
import { AsyncCallback } from '@ohos.base';
import { ElementName } from './bundleManager/ElementName'

let hceService: cardEmulation.HceService = new cardEmulation.HceService();
let element: ElementName;

export default class EntryAbility extends UIAbility {
  onCreate(want, launchParam) {
    hilog.info(0x0000, 'testHce', '%{public}s', 'Ability onCreate');
    element = {
      bundleName: want.bundleName,
      abilityName: want.abilityName,
      moduleName: want.moduleName
    }
    const apduCallback: AsyncCallback<number[]> = (err, data) => {
      //handle the data and err
      console.log("got apdu data");
    };
    hceService.on('hceCmd', apduCallback);
  }
  onDestroy() {
    hilog.info(0x0000, 'testHce', '%{public}s', 'Ability onDestroy');
    hceService.stop(element)
  }
  // other life cycle method...
}

sendResponse^(deprecated)

sendResponse(responseApdu: number[]): void

Sends a response to the peer card reader. This API is used only for declaration and cannot be used currently.

NOTE This API is supported since API version 8 and deprecated since API version 9. Use transmit instead.

Required permissions: ohos.permission.NFC_CARD_EMULATION

System capability: SystemCapability.Communication.NFC.CardEmulation

Parameters

transmit⁹⁺

transmit(response: number[]): Promise<void>

Transmits an APDU to the peer card reader. This API uses a promise to return the result. The application calls this API only after receiving an APDU sent by the card reader via on.

Required permissions: ohos.permission.NFC_CARD_EMULATION

System capability: SystemCapability.Communication.NFC.CardEmulation

Ability API set: Since API version 12, this API can be used in abilities.

Parameters

Return value

Error codes

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

Example

import cardEmulation from '@ohos.nfc.cardEmulation';
import { BusinessError } from '@ohos.base';

let hceService: cardEmulation.HceService = new cardEmulation.HceService();

// the data app wanna send, just a example data
const responseData = [0x1, 0x2];
hceService.transmit(responseData).then(() => {
  // handle the transmit promise
  console.log("transmit Promise success.");
}).catch((err: BusinessError) => {
  console.log("transmit Promise error:", err);
});

transmit⁹⁺

transmit(response: number[], callback: AsyncCallback<void>): void

Transmits an APDU to the peer card reader. This API uses an asynchronous callback to return the result. The application calls this API only after receiving an APDU sent by the card reader via on.

Required permissions: ohos.permission.NFC_CARD_EMULATION

System capability: SystemCapability.Communication.NFC.CardEmulation

Ability API set: Since API version 12, this API can be used in abilities.

Parameters

Error codes

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

Example

import cardEmulation from '@ohos.nfc.cardEmulation';
import { BusinessError } from '@ohos.base';

let hceService: cardEmulation.HceService = new cardEmulation.HceService();

// the data app wanna send, just a example data
try {
  const responseData = [0x1, 0x2];

  hceService.transmit(responseData, (err : BusinessError)=> {
    if (err) {
      console.error("transmit AsyncCallback err Code: ${err.code}, message: ${err.message}");
    } else {
      console.log("transmit AsyncCallback success.");
    }
  });
} catch (busiError) {
  console.error("transmit AsyncCallback catch Code: ${(busiError as Businsess).code}, " +
    "message: ${(busiError as Businsess).message}");
}