详细记录一下鸿蒙系统版本的微信支付开发过程，避免日后踩坑。

一、微信后台添加应用并配置鸿蒙应用信息

首先要在微信开放平台（https://open.weixin.qq.com）添加应用，配置鸿蒙应用信息并审核通过。

Bundle ID：指的是鸿蒙应用的包名

Identifier：指的是鸿蒙应用的 appIdentifier

获取方法一：华为应用后台获取

华为应用管理 —> 我的项目 —> 项目设置 —> OAuth 2.0客户端ID —> Client ID

Client ID 就是鸿蒙应用的 appIdentifier

获取方法二：代码获取

bundleManager.getBundleInfoForSelf(bundleManager.BundleFlag.GET_BUNDLE_INFO_WITH_SIGNATURE_INFO).then((info) => {
    let appIdentifier = info.signatureInfo.appIdentifier
    LogUtil.debug("[EntryAbility]appIdentifier：" + appIdentifier)
  })

二、引入微信SDK

在项目级或者应用级的oh-package.json5文件中的dependencies增加微信sdk库，注意修改sdk最新的版本号

"dependencies": {
    "@tencent/wechat_open_sdk": "1.0.14"
  }

三、增加微信SDK回调类

新建文件WXApiWrap.ets,代码如下

import * as wxopensdk from '@tencent/wechat_open_sdk';
import { LogUtil } from '../utils/LogUtil';

export type OnWXReq = (req: wxopensdk.BaseReq) => void
export type OnWXResp = (resp: wxopensdk.BaseResp) => void

const kTag = "WXApiEventHandlerImpl"

class WXApiEventHandlerImpl implements wxopensdk.WXApiEventHandler {
  private onReqCallbacks: Map<OnWXReq, OnWXReq> = new Map
  private onRespCallbacks: Map<OnWXResp, OnWXResp> = 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): void {
    wxopensdk.Log.i(kTag, "onReq:%s", JSON.stringify(req))
    LogUtil.debug("[WXApiEventHandlerImpl]onReq",JSON.stringify(req))
    this.onReqCallbacks.forEach((on) => {
      on(req)
    })
  }

  onResp(resp: wxopensdk.BaseResp): void {
    wxopensdk.Log.i(kTag, "onResp:%s", JSON.stringify(resp))
    LogUtil.debug("[WXApiEventHandlerImpl]onResp",JSON.stringify(resp))
    this.onRespCallbacks.forEach((on) => {
      on(resp)
    })
  }
}

export const WXApi = wxopensdk.WXAPIFactory.createWXAPI("填写微信后台移动应用的APPID")
export const WXEventHandler = new WXApiEventHandlerImpl

四、在EntryAbility中响应来自微信的回调

在应用启动类EntryAbility.ets中添加如下代码：

export default class EntryAbility extends UIAbility {
  onCreate(want: Want, _launchParam: AbilityConstant.LaunchParam): void {
    this.handleWeChatCallIfNeed(want)
  }
  
  onNewWant(want: Want, _launchParam: AbilityConstant.LaunchParam): void {
    this.handleWeChatCallIfNeed(want)
  }

  private handleWeChatCallIfNeed(want: Want) {
    WXApi.handleWant(want, WXEventHandler)
  }
}

主要是添加handleWeChatCallIfNeed函数，然后在EntryAbility的onCreate和onNewWant生命周期中调用该函数

五、生成订单

1、服务端需要集成微信支付SDK

2、客户端调用服务端接口，进行预下单，并返回订单信息partnerId、prepayId、noncestr、timestamp、sign等字段

六、调用微信支付

1、定义微信wxApi、wxEventHandler对象和OnWXResp回调

@State payResultText: string = ''
private wxApi = WXApi
private wxEventHandler = WXEventHandler
private onWXResp: OnWXResp = (resp) => {
  this.payResultText = JSON.stringify(resp ?? {}, null, 2)
  LogUtil.debug("[BuyVipPage]onWXResp payResultText",this.payResultText)
  if(resp["errCode"] === ErrCode.ERR_OK ){
    emitter.emit(MessageEvent.BUY_VIP_SUCCESS,{priority:emitter.EventPriority.HIGH})
    router.back()
  }else if (resp["errCode"] === ErrCode.ERR_USER_CANCEL){
    promptAction.showToast({
      message: "取消支付",
      duration: 1000
    })
  }else {
    promptAction.showToast({
      message: "支付失败，请稍后重试或联系客服",
      duration: 3000
    })
  }
}

2、注册微信登录回调

在aboutToAppear生命周期中注册微信登录回调，在aboutToDisappear生命周期中销毁微信登录回调

aboutToAppear(): void {
  this.wxEventHandler.registerOnWXRespCallback(this.onWXResp)
}

aboutToDisappear(): void {
  this.wxEventHandler.unregisterOnWXRespCallback(this.onWXResp)
}

3、发起支付

let req = new wxopensdk.PayReq
    req.partnerId = orderInfo.partnerId
    req.appId = WechatConstants.APPID
    req.packageValue = 'Sign=WXPay'
    req.prepayId = orderInfo.prepayId
    req.nonceStr = orderInfo.noncestr
    req.timeStamp = orderInfo.timestamp
    req.sign = orderInfo.sign
    let finished = await this.wxApi.sendReq(getContext(this) as common.UIAbilityContext, req)
    console.log("send request finished: ", finished)

支付结束后，会在onWXResp回调里面返回支付结果

尚拙

HarmonyOS Next 微信支付开发指南