第一步： 不管微信登录，微信支付，微信分享都需要到微信开放平台注册账号后并注册应用，拿到应用唯一标识AppID和应用密钥 AppSecret

然后集成SDK,具体如何集成查看官方文档，文档有详细介绍
微信开放平台–iOS 接入指南

第二步：微信SDK初始化，注意universal_link必须添加

 let universal_link = "https://wx.universal_link.url" //此处填写微信后台写的universal_link 地址
 WXApi.registerApp(WX_APPID, universalLink: universal_link)

设置universalLink

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微信配置代理，接收微信请求后的返回信息（用户登录/微信支付订单信息）

 // 9.0之后  打开第三方应用之后返回程序内  设置系统回调  --------待完善---------
    func application(_ app: UIApplication, open url: URL, options: [UIApplication.OpenURLOptionsKey : Any] = [:]) -> Bool {
        if url.absoluteString.hasPrefix(WX_APPID){
            //微-信
            WXApi.handleOpen(url, delegate: NK_WXUtils.sharedManager)
            return true
        }
     }
    func application(_ application: UIApplication, continue userActivity: NSUserActivity, restorationHandler: @escaping ([UIUserActivityRestoring]?) -> Void) -> Bool {
        
        if userActivity.activityType == NSUserActivityTypeBrowsingWeb {
            if let url = userActivity.webpageURL{
                    return WXApi.handleOpenUniversalLink(userActivity, delegate: NK_WXUtils.sharedManager)
            }
            
        }
        return true
    }

微信调用方法

class NK_WXUtils: NSObject , WXApiDelegate{

    //微信登录
    static func wxLogin(){
        
        if WXApi.isWXAppInstalled() {
            let req = SendAuthReq()
            req.state = "wx_oauth_authorization_state";//用于保持请求和回调的状态，授权请求或原样带回
            req.scope = "snsapi_userinfo";//授权作用域：获取用户个人信息
            // req.scope = "snsapi_userinfo,snsapi_base";//授权作用域：获取用户个人信息
            
            DispatchQueue.main.async {
                WXApi.send(req)
            }
        }else{
            MBProgressHUD.showJustText(msg: "您尚未安装微信客户端，请安装后重试!")
        }
        
    }

    //微信发送请求，这里不用处理
    func onReq(_ req: BaseReq) {
        
        MYLog( "\n\n----openID:"+req.openID)
    }
    //微信请求返回结果，这里处理返回的结果
    func onResp(_ resp: BaseResp) {
        if resp.isKind(of: SendAuthResp.self) {
            let res = resp as? SendAuthResp
            if res?.state == "wx_oauth_authorization_state" {
                NK_WXUtils.getWechatAccessToken(code: res!.code!)
            }
        }
    }


    static func getWechatAccessToken(code:String)  {
        
        let url = "https://api.weixin.qq.com/sns/oauth2/access_token?appid=\(WX_APPID)&secret=\(WX_SECRET)&code=\(code)&grant_type=authorization_code"
        MBProgressHUD.showLoadingHUD(msg: nil, view: nil)
        NK_HttpManager().requestData(with: url, cache: false, method: .get, params: nil).success { (code, res) in
            MYLog(res)
            guard let dic = res as? [String: Any] else{
                return
            }
            
            guard let access_token = dic["access_token"] as? String,  let openid = dic["openid"] as? String else{
                MBProgressHUD.hideToastHUD(view: nil)
                return
            }
            getWechatUserInfo(with: access_token, openId: openid )
           
            }.fail { (error, msg) in
//                MYLog(msg)
                MBProgressHUD.showJustText(msg: msg)
        }
        
    }
    
    
    static func getWechatUserInfo(with access_token:String, openId:String)  {

        let url = "https://api.weixin.qq.com/sns/userinfo?access_token=\(access_token)&openid=\(openId)"
        NK_HttpManager().requestData(with: url, cache: false, method: .get, params: nil).success { (code, res) in
            MBProgressHUD.hideToastHUD(view: nil)
        //            MYLog(res)
            if let dic = res as? [String: Any]{
                // 获取到的用户信息json格式，可以拿来给服务端绑定用户信息
            }
            
            }.fail { (error, msg) in
                MBProgressHUD.showJustText(msg: msg)
        }
    }
    
}