文章目录
一、简介二、场景介绍三、接口说明四、开发步骤
一、简介
近场通信(Near Field Communication，NFC)是一种短距高频的无线电技术，在13.56MHz频率运行，通信距离一般在10厘米距离内。HCE(Host Card Emulation)，称为基于主机的卡模拟，表示不依赖安全单元芯片，电子设备上的应用程序模拟NFC卡片和NFC读卡器通信，实现NFC刷卡业务。
二、场景介绍
应用程序模拟NFC卡片，和NFC读卡器通信完成NFC刷卡业务。从使用场景上，可以分成HCE应用前台刷卡，和HCE应用后台刷卡。
HCE应用前台刷卡
前台刷卡是指在触碰NFC读卡器之前，用户先在电子设备上打开特定的应用程序，用户明确想使用所打开的应用程序和NFC读卡器进行刷卡操作。用户打开应用程序在前台，并且进入应用的刷卡页面之后，电子设备触碰NFC读卡器，只会把刷卡交易数据分发给前台应用。
HCE应用后台刷卡
后台刷卡是指不打开特定的HCE应用程序，电子设备触碰NFC读卡器后，根据NFC读卡器选择的应用ID（AID）匹配到HCE应用程序，并自动和匹配的HCE应用程序通信完成刷卡交易。如果匹配到多个HCE应用程序时，说明存在冲突，需要用户打开指定的应用才能完成刷卡。
HCE应用刷卡的约束条件
1、不管是HCE应用前台还是后台刷卡，能够完成HCE应用程序NFC刷卡的条件是电子设备需要亮屏解锁。
2、module.json5文件中需要声明nfc卡模拟权限，具体见示例。
3、前台应用时需要调用start和stop注册和去注册AID，具体见示例。
三、接口说明
NFC卡模拟完整的JS API说明以及实例代码请参考：NFC卡模拟接口。
完成HCE卡模拟功能，可能使用到下面的接口。
接口名功能描述start(elementName: ElementName, aidList: string[]): void启动HCE业务功能。包括设置当前应用为前台优先，动态注册AID列表。stop(elementName: ElementName): void停止HCE业务功能。包括取消APDU数据接收的订阅，退出当前应用前台优先，释放动态注册的AID列表。on(type: ‘hceCmd’, callback: AsyncCallback
四、开发步骤
HCE应用前台刷卡
在module.json5文件中声明NFC卡模拟权限，以及声明HCE特定的action。import需要的NFC卡模拟模块和其他相关的模块。判断设备是否支持NFC能力和HCE能力。使能前台HCE应用程序优先处理NFC刷卡功能。订阅HCE APDU数据的接收。完成HCE刷卡APDU数据的接收和发送。退出应用程序NFC刷卡页面时，退出前台优先功能。
"abilities": [
{
"name": "EntryAbility",
"srcEntry": "./ets/entryability/EntryAbility.ts",
"description": "$string:EntryAbility_desc",
"icon": "$media:icon",
"label": "$string:EntryAbility_label",
"startWindowIcon": "$media:icon",
"startWindowBackground": "$color:start_window_background",
"exported": true,
"skills": [
{
"entities": [
"entity.system.home"
],
"actions": [
"action.system.home",
// Add the nfc card emulation action to filter out for this application.
"ohos.nfc.cardemulation.action.HOST_APDU_SERVICE"
]
}
]
}
],
"requestPermissions": [
{
// Add the permission for nfc card emulation.
"name": "ohos.permission.NFC_CARD_EMULATION",
"reason": "$string:app_name",
}
]
import { cardEmulation } from '@kit.ConnectivityKit';
import { BusinessError } from '@kit.BasicServicesKit';
import { hilog } from '@kit.PerformanceAnalysisKit';
import { AsyncCallback } from '@kit.BasicServicesKit';
import { AbilityConstant, UIAbility, Want, bundleManager } from '@kit.AbilityKit';
let hceElementName: bundleManager.ElementName;
let hceService: cardEmulation.HceService;
const hceCommandCb : AsyncCallback
if (!error) {
if (hceCommand == null || hceCommand == undefined) {
hilog.error(0x0000, 'testTag', 'hceCommandCb has invalid hceCommand.');
return;
}
// check the command, then transmit the response.
hilog.info(0x0000, 'testTag', 'hceCommand = %{public}s', JSON.stringify(hceCommand));
let responseData = [0x90, 0x00]; // change the response depend on different received command.
hceService.transmit(responseData).then(() => {
hilog.info(0x0000, 'testTag', 'hceService transmit Promise success.');
}).catch((err: BusinessError) => {
hilog.error(0x0000, 'testTag', 'hceService transmit Promise error = %{public}s', JSON.stringify(err));
});
} else {
hilog.error(0x0000, 'testTag', 'hceCommandCb error %{public}s', JSON.stringify(error));
}
}
export default class EntryAbility extends UIAbility {
onCreate(want: Want, launchParam: AbilityConstant.LaunchParam) {
hilog.info(0x0000, 'testTag', '%{public}s', 'Ability onCreate');
// 判断设备是否支持NFC能力和HCE能力
if (!canIUse("SystemCapability.Communication.NFC.Core")) {
hilog.error(0x0000, 'testTag', 'nfc unavailable.');
return;
}
if (!cardEmulation.hasHceCapability()) {
hilog.error(0x0000, 'testTag', 'hce unavailable.');
return;
}
hceElementName = {
bundleName: want.bundleName ?? '',
abilityName: want.abilityName ?? '',
moduleName: want.moduleName,
}
hceService = new cardEmulation.HceService();
}
onForeground() {
// Ability has brought to foreground
hilog.info(0x0000, 'testTag', '%{public}s', 'Ability onForeground');
if (hceElementName != undefined) {
try {
// 调用接口使能前台HCE应用程序优先处理NFC刷卡功能
let aidList = ["A0000000031010", "A0000000031011"]; // change aid tobe correct.
hceService.start(hceElementName, aidList);
// 订阅HCE APDU数据的接收
hceService.on('hceCmd', hceCommandCb);
} catch (error) {
hilog.error(0x0000, 'testTag', 'hceService.start error = %{public}s', JSON.stringify(error));
}
}
}
onBackground() {
// Ability has back to background
hilog.info(0x0000, 'testTag', '%{public}s', 'Ability onBackground');
// 退出应用程序NFC标签页面时，调用tag模块退出前台优先功能
if (hceElementName != undefined) {
try {
hceService.stop(hceElementName);
} catch (error) {
hilog.error(0x0000, 'testTag', 'hceService.stop error = %{public}s', JSON.stringify(error));
}
}
}
}
HCE应用后台刷卡
在module.json5文件中声明NFC卡模拟权限，声明HCE特定的action，声明应用能够处理的AID。import需要的NFC卡模拟模块和其他相关的模块。判断设备是否支持NFC能力和HCE能力。订阅HCE APDU数据的接收。完成HCE刷卡APDU数据的接收和发送。退出应用程序时，退出订阅功能。
"abilities": [
{
"name": "EntryAbility",
"srcEntry": "./ets/entryability/EntryAbility.ts",
"description": "$string:EntryAbility_desc",
"icon": "$media:icon",
"label": "$string:EntryAbility_label",
"startWindowIcon": "$media:icon",
"startWindowBackground": "$color:start_window_background",
"exported": true,
"skills": [
{
"entities": [
"entity.system.home"
],
"actions": [
"action.system.home",
// Add the nfc card emulation action to filter out for this application.
"ohos.nfc.cardemulation.action.HOST_APDU_SERVICE"
]
}
],
"metadata": [
{
"name": "payment-aid",
"value": "A0000000031010" // change it tobe correct
},
{
"name": "other-aid",
"value": "A0000000031011" // change it tobe correct
}
]
}
],
"requestPermissions": [
{
// Add the permission for nfc card emulation.
"name": "ohos.permission.NFC_CARD_EMULATION",
"reason": "$string:app_name",
}
]
import { cardEmulation } from '@kit.ConnectivityKit';
import { BusinessError } from '@kit.BasicServicesKit';
import { hilog } from '@kit.PerformanceAnalysisKit';
import { AsyncCallback } from '@kit.BasicServicesKit';
import { AbilityConstant, UIAbility, Want, bundleManager } from '@kit.AbilityKit';
let hceElementName : bundleManager.ElementName;
let hceService: cardEmulation.HceService;
const hceCommandCb : AsyncCallback
if (!error) {
if (hceCommand == null || hceCommand == undefined) {
hilog.error(0x0000, 'testTag', 'hceCommandCb has invalid hceCommand.');
return;
}
// check the command, then transmit the response.
hilog.info(0x0000, 'testTag', 'hceCommand = %{public}s', JSON.stringify(hceCommand));
let responseData = [0x90, 0x00]; // change the response depend on different received command.
hceService.transmit(responseData).then(() => {
hilog.info(0x0000, 'testTag', 'hceService transmit Promise success.');
}).catch((err: BusinessError) => {
hilog.error(0x0000, 'testTag', 'hceService transmit Promise error = %{public}s', JSON.stringify(err));
});
} else {
hilog.error(0x0000, 'testTag', 'hceCommandCb error %{public}s', JSON.stringify(error));
}
}
export default class EntryAbility extends UIAbility {
onCreate(want: Want, launchParam: AbilityConstant.LaunchParam) {
hilog.info(0x0000, 'testTag', '%{public}s', 'Ability onCreate');
// 判断设备是否支持NFC能力和HCE能力
if (!canIUse("SystemCapability.Communication.NFC.Core")) {
hilog.error(0x0000, 'testTag', 'nfc unavailable.');
return;
}
if (!cardEmulation.hasHceCapability()) {
hilog.error(0x0000, 'testTag', 'hce unavailable.');
return;
}
hceElementName = {
bundleName: want.bundleName ?? '',
abilityName: want.abilityName ?? '',
moduleName: want.moduleName,
}
hceService = new cardEmulation.HceService();
hceService.on('hceCmd', hceCommandCb);
}
onForeground() {
// Ability has brought to foreground
hilog.info(0x0000, 'testTag', '%{public}s', 'Ability onForeground');
}
onDestroy() {
// Ability has back to destroy
hilog.info(0x0000, 'testTag', '%{public}s', 'Ability onDestroy');
// 退出应用程序NFC标签页面时，调用tag模块退出前台优先功能
if (hceElementName != undefined) {
try {
hceService.stop(hceElementName);
} catch (error) {
hilog.error(0x0000, 'testTag', 'hceService.stop error = %{public}s', JSON.stringify(error));
}
}
}
}