iOS swift 微信App授权登录/网页版授权登录

一、向微信开放平台申请创建应用

1、申请（微信开放后台）链接：https://open.weixin.qq.com/cgi-bin/frame?t=home/app_tmpl&lang=zh_CN
接入指南：https://developers.weixin.qq.com/doc/oplatform/Mobile_App/Access_Guide/iOS.html

二、接入后初始化并进行授权登录的操作

1、引入头文件，比如在桥接文件中引入：#import <WechatOpenSDK/WXApi.h>
2、初始化SDK，比如在didFinishLaunchingWithOptions方法中初始化

//微信SDK初始化
func initializeWeixinSDK(){
    //在微信开放平台创建应用后申请到的appId
    let wxappId = "你自己App的ID"    
    //在微信开放平台创建应用时填写的universal link
    let universalLinks = "你自己App的universal link"
    WXApi.registerApp(wxappId, universalLink: universalLinks)
    //此处时开启微信SDK的调试log，不需要调试的可注释调
    WXApi.startLog(by: .detail) { str in
        FPPrint("=========微信登录============\(str)")
    }
}

3、重写应用的三个方法（三个方法都重写，目的是兼容低版本系统）

func pplication( _ app:UIApplication, open url:URL, options: [UIApplication.OpenURLOptionsKey :Any] = [:]) -> Bool{
    //url.host == "oauth":微信app授权跳转回到自身app时的判断
    //url.host == "wapoauth":网页授权跳转回到自身app时的判断
    //url.host == nil:微信app授权，点击取消时跳转回到自身app时的判断
        if url.host == "oauth" || url.host == "wapoauth" || url.host == nil {
            //设置授权成功/取消后接受回调的代理
            return WXApi.handleOpen(url, delegate: self)
        }
        return true
}
func application(_ application: UIApplication, handleOpen url: URL) -> Bool {
        WXApi.handleOpen(url, delegate: self)
    }
    func application(_ application: UIApplication, open url: URL, sourceApplication: String?, annotation: Any) -> Bool {
        WXApi.handleOpen(url, delegate: self)
    }

4、点击按钮进行登录的代码

func sendWXAuthReq(){
        //是否安装微信App
        if  WXApi.isWXAppInstalled() {
            let sendAuth = SendAuthReq()
            sendAuth.scope = "snsapi_userinfo"//授权作用域：获取用户个人信息
            sendAuth.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
            WXApi.send(sendAuth) { _ in
                
            }
        }else{
            //未安装微信App，使用网页授权方式进行授权登录
            //但是根据官方文档解析：最好是判断是否安装微信来显示微信授权登录按钮，这样可以更好的规避app被拒绝的风险
            let sendAuth = SendAuthReq()
            sendAuth.scope = "snsapi_userinfo"//授权作用域：获取用户个人信息
            sendAuth.state = "pedometer_binding"//用于保持请求和回调的状态，授权请求或原样带回
            DispatchQueue.main.async {
                WXApi.sendAuthReq(sendAuth, viewController: self, delegate: appDelegate, completion: nil)
            }
        }
    }

5、接受回调的方法（WXApiDelegate的方法）

//授权成功/取消授权回调的方法：网页和app授权都是走这个方法，后面会细说网页授权的原理
func onResp(_ resp: BaseResp) {
        if resp.isKind(of: SendAuthResp.self){
            let response = resp as! SendAuthResp
            let errorCode = response.errCode
            if errorCode != 0{
                //授权失败，根据自身需要进行一些处理
                return
            }
            if let code = response.code{
                DispatchQueue.main.async {
                    //获取openId和access_token
                    self.getWXOpenId(code: code)
                }
            }else{
                //=====微信登录========code为空======
            }
        }
    }
    //获取openID和access_token来获取微信用户的头像/昵称等
    func getWXOpenId(code:String){
        DispatchQueue.global().async {[weak self] in
            let appId = "自身appId"//微信开放平台申请的appid
            let secret = "secretkey"微信开放平台申请的secretkey
            let codeStr = code
            let grantType = "authorization_code"//类型，直接赋予该值即可
            let urlStr = "https://api.weixin.qq.com/sns/oauth2/access_token?appid=\(appId)&secret=\(secret)&code=\(codeStr)&grant_type=\(grantType)"
            if let url = URL(string: urlStr){
                if let zoneStr = try? String(contentsOf: url){
                    if let data = zoneStr.data(using: .utf8){
                        if let dataDict = try? JSONSerialization.jsonObject(with: data, options: .allowFragments) as? [String:Any]{
                            let openId = dataDict["openid"] as? String
                            let accessToken = dataDict["access_token"] as? String
                            if openId != nil && accessToken != nil{
                            //获取微信用户信息
                            self?.getWXUserInfo(accessToken: accessToken!, openId: openId!)
                            }
                        }else{
                        //获取失败
                        }
                    }else{
                        //获取失败
                    }
                }else{
                    //获取失败
                }
            }else{
                //获取失败
            }
        }
    }
//获取用户信息：昵称/头像等
func getWXUserInfo(accessToken:String,openId:String){
        DispatchQueue.global().async {[weak self] in
            let urlStr = "https://api.weixin.qq.com/sns/userinfo?access_token=\(accessToken)&openid=\(openId)"
            if let url = URL(string: urlStr){
                if let zoneStr = try? String(contentsOf: url){
                    if let data = zoneStr.data(using: .utf8){
                        if let dataDict = try? JSONSerialization.jsonObject(with: data, options: .allowFragments) as? [String:Any]{
                            //获取成功，根据自身需要取值进行相应的操作
                        }else{
                            //获取失败
                        }
                    }else{
                       //获取失败
                    }
                }else{
                    //获取失败
                }
            }else{
                //获取失败
            }
        }
    }