HarmonyOS Flutter: Simplified WeChat Pay Integration

HarmonyOS Flutter: Simplified WeChat Pay Integration I. Configure HarmonyOS Application Information Important Notes Refer to the official WeChat Pay documentation: https://pay.weixin.qq.com/doc/v3/merchant/4012073588#%E9%B8%BF%E8%92%99-SDK-%E8%B0%83%E7%94%A8%E8%AF%B4%E6%98%8E Key Configuration Requirements: Bundle ID: The package name of your HarmonyOS app. Identifier: Your app’s unique identifier (App ID obtained from WeChat Open Platform). Critical Warning: If your app is already published on Android/iOS markets, do not select "Not published on any market". This option restricts WeChat Pay functionality unless all platforms (Android, iOS, HarmonyOS) are unpublished. II. SDK Dependency Configuration { "name": "demo", "version": "1.0.0", "description": "Describe the basic app info.", "main": "", "author": "", "license": "", "dependencies": { "@tencent/wechat_open_sdk": "1.0.0" // WeChat Open SDK dependency } } III. Ohos-Side Integration 1. Initialize WeChat API import * as wxopensdk from '@wechat/open_sdk'; // Create WXAPI instance with your App ID export const WXApi = wxopensdk.WXAPIFactory.createWXAPI(APP_ID); // Define callback handler for WeChat responses class WXApiEventHandlerImpl implements wxopensdk.WXApiEventHandler { private onReqCallbacks = new Map(); private onRespCallbacks = new Map(); registerOnWXReqCallback(on: OnWXReq) { this.onReqCallbacks.set(on, on); } unregisterOnWXReqCallback(on: OnWXReq) { this.onReqCallbacks.delete(on); } registerOnWXRespCallback(on: OnWXResp) { this.onRespCallbacks.set(on, on); } unregisterOnWXRespCallback(on: OnWXResp) { this.onRespCallbacks.delete(on); } onReq(req: wxopensdk.BaseReq) { Log.i(kTag, `onReq: ${JSON.stringify(req)}`); this.onReqCallbacks.forEach((callback) => callback(req)); } onResp(resp: wxopensdk.BaseResp) { Log.i(kTag, `onResp: ${JSON.stringify(resp)}`); this.onRespCallbacks.forEach((callback) => callback(resp)); } } export const WXEventHandler = new WXApiEventHandlerImpl(); 2. Initiate Payment // Build payment request let req = new wxopensdk.PayReq(); req.appId = 'wxd930ea5d5a258f4f'; // Your WeChat App ID req.partnerId = '1900000109'; // Your WeChat Merchant ID req.prepayId = '1101000000140415649af9fc314aa427'; // Prepay ID from WeChat Pay API req.packageValue = 'Sign=WXPay'; // Fixed value req.nonceStr = '1101000000140429eb40476f8896f4c9'; // Random string (≤32 chars) req.timeStamp = '1398746574'; // Timestamp req.sign = '7FFECB600D7157C5AA49810D2D8F28BC2811827B'; // Signature // Send payment request to WeChat let finished = await WXApi.sendReq( context: common.UIAbilityContext, // Required for inter-app navigation req: req ); IV. Flutter Plugin Channel Setup 1. Flutter Side Implementation class WeChatPayPlugin { static const MethodChannel _channel = MethodChannel('wechat_pay'); // Initialize WeChat API Future registerWxApi(String appId) async { return await _channel.invokeMethod('registerWxApi', appId); } // Trigger WeChat Pay Future payWithWeChat({ required String appId, required String partnerId, required String prepayId, required String packageValue, required String nonceStr, required int timeStamp, required String sign, String? signType, String? extData, }) async { return await _channel.invokeMethod('payWithWeChat', { 'appId': appId, 'partnerId': partnerId, 'prepayId': prepayId, 'packageValue': packageValue, 'nonceStr': nonceStr, 'timeStamp': timeStamp, 'sign': sign, 'signType': signType, 'extData': extData, }); } } V. External Invocation Example // Call WeChat Pay from Flutter WeChatPayPlugin().payWithWeChat( appId: itemMap['appid'].toString(), partnerId: itemMap['partnerid'].toString(), prepayId: itemMap['prepayid'].toString(), packageValue: itemMap['package'].toString(), nonceStr: itemMap['noncestr'].toString(), timeStamp: int.parse(itemMap['timestamp']), sign: itemMap['sign'].toString(), ).then((success) { print('--- Payment Result: $success'); }); VI. Key Notes Lifecycle Handling: In your HarmonyOS EntryAbility , override onCreate and onNewWant to handle WeChat callbacks: @Override public void onCreate(Want want, LaunchParam launchParam) { super.onCreate(want, launchParam); WXEventHandler.handleWant(want); // Pass intents to WeChat handler } Security: Ensure all sensitive data (e.g., partnerId, sign) is securely stored and transmitted. Testing: Test with a valid WeChat sandbox account before production deployment.

Jun 27, 2025 - 03:20

HarmonyOS Flutter: Simplified WeChat Pay Integration

I. Configure HarmonyOS Application Information

Important Notes

Refer to the official WeChat Pay documentation:
https://pay.weixin.qq.com/doc/v3/merchant/4012073588#%E9%B8%BF%E8%92%99-SDK-%E8%B0%83%E7%94%A8%E8%AF%B4%E6%98%8E

Key Configuration Requirements:

Bundle ID: The package name of your HarmonyOS app.
Identifier: Your app’s unique identifier (App ID obtained from WeChat Open Platform).

Critical Warning:

If your app is already published on Android/iOS markets, do not select "Not published on any market". This option restricts WeChat Pay functionality unless all platforms (Android, iOS, HarmonyOS) are unpublished.

II. SDK Dependency Configuration

{
  "name": "demo",
  "version": "1.0.0",
  "description": "Describe the basic app info.",
  "main": "",
  "author": "",
  "license": "",
  "dependencies": {
    "@tencent/wechat_open_sdk": "1.0.0" // WeChat Open SDK dependency
  }
}

III. Ohos-Side Integration

1. Initialize WeChat API

import * as wxopensdk from '@wechat/open_sdk';

// Create WXAPI instance with your App ID
export const WXApi = wxopensdk.WXAPIFactory.createWXAPI(APP_ID);

// Define callback handler for WeChat responses
class WXApiEventHandlerImpl implements wxopensdk.WXApiEventHandler {
  private onReqCallbacks = new Map();
  private onRespCallbacks = new Map();

  registerOnWXReqCallback(on: OnWXReq) {
    this.onReqCallbacks.set(on, on);
  }

  unregisterOnWXReqCallback(on: OnWXReq) {
    this.onReqCallbacks.delete(on);
  }

  registerOnWXRespCallback(on: OnWXResp) {
    this.onRespCallbacks.set(on, on);
  }

  unregisterOnWXRespCallback(on: OnWXResp) {
    this.onRespCallbacks.delete(on);
  }

  onReq(req: wxopensdk.BaseReq) {
    Log.i(kTag, `onReq: ${JSON.stringify(req)}`);
    this.onReqCallbacks.forEach((callback) => callback(req));
  }

  onResp(resp: wxopensdk.BaseResp) {
    Log.i(kTag, `onResp: ${JSON.stringify(resp)}`);
    this.onRespCallbacks.forEach((callback) => callback(resp));
  }
}

export const WXEventHandler = new WXApiEventHandlerImpl();

2. Initiate Payment

// Build payment request
let req = new wxopensdk.PayReq();
req.appId = 'wxd930ea5d5a258f4f'; // Your WeChat App ID
req.partnerId = '1900000109'; // Your WeChat Merchant ID
req.prepayId = '1101000000140415649af9fc314aa427'; // Prepay ID from WeChat Pay API
req.packageValue = 'Sign=WXPay'; // Fixed value
req.nonceStr = '1101000000140429eb40476f8896f4c9'; // Random string (≤32 chars)
req.timeStamp = '1398746574'; // Timestamp
req.sign = '7FFECB600D7157C5AA49810D2D8F28BC2811827B'; // Signature

// Send payment request to WeChat
let finished = await WXApi.sendReq(
  context: common.UIAbilityContext, // Required for inter-app navigation
  req: req
);

IV. Flutter Plugin Channel Setup

1. Flutter Side Implementation

class WeChatPayPlugin {
  static const MethodChannel _channel = MethodChannel('wechat_pay');

  // Initialize WeChat API
  Future registerWxApi(String appId) async {
    return await _channel.invokeMethod('registerWxApi', appId);
  }

  // Trigger WeChat Pay
  Future payWithWeChat({
    required String appId,
    required String partnerId,
    required String prepayId,
    required String packageValue,
    required String nonceStr,
    required int timeStamp,
    required String sign,
    String? signType,
    String? extData,
  }) async {
    return await _channel.invokeMethod('payWithWeChat', {
      'appId': appId,
      'partnerId': partnerId,
      'prepayId': prepayId,
      'packageValue': packageValue,
      'nonceStr': nonceStr,
      'timeStamp': timeStamp,
      'sign': sign,
      'signType': signType,
      'extData': extData,
    });
  }
}

V. External Invocation Example

// Call WeChat Pay from Flutter
WeChatPayPlugin().payWithWeChat(
  appId: itemMap['appid'].toString(),
  partnerId: itemMap['partnerid'].toString(),
  prepayId: itemMap['prepayid'].toString(),
  packageValue: itemMap['package'].toString(),
  nonceStr: itemMap['noncestr'].toString(),
  timeStamp: int.parse(itemMap['timestamp']),
  sign: itemMap['sign'].toString(),
).then((success) {
  print('--- Payment Result: $success');
});

VI. Key Notes

Lifecycle Handling:

In your HarmonyOS

 EntryAbility

, override

 onCreate

and

 onNewWant

to handle WeChat callbacks:

 @Override
 public void onCreate(Want want, LaunchParam launchParam) {
   super.onCreate(want, launchParam);
   WXEventHandler.handleWant(want); // Pass intents to WeChat handler
 }

Security:

Ensure all sensitive data (e.g., partnerId, sign) is securely stored and transmitted.

Testing:

Test with a valid WeChat sandbox account before production deployment.