殺毒App（iOS）后Facebook AccessToken無

Question

我正在使用FacebookSDK開發一個iOS應用程序來登錄。

登錄並終止App后， currentAccessToken始終為nil。 它只有在我按下主頁按鈕並重新打開應用程序時才有效，因為它仍然在后台運行 。

我開始使用警報，因為殺死應用程序后日志無法正常工作。

AppDelegate.swift

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {

    FBSDKApplicationDelegate.sharedInstance().application(application, didFinishLaunchingWithOptions: launchOptions)

    let accessToken = FBSDKAccessToken.current()
    if accessToken == nil {
        Auth.auth().addStateDidChangeListener { (auth, user) in
            alert(title: user?.uid ?? "1")
        }
        alert(title: "2")
    } else {
        alert(title: accessToken?.userID ?? "3")
    }
}

它始終在警報中顯示“1”。

這是一個類似的問題： FBSDKAccessToken currentAccessToken nil退出應用程序或iOS 9 Facebook Access令牌在未來的應用程序發布時為零

我曾經嘗試過：

1. 鑰匙串不起作用
2. 通過Cocoapods降級至4.17無法降級
3. 改變運輸安全也不行

幫助/建議，

提前致謝。

Answer 1

AccessToken.current不會持久存在，因此您必須手動保存訪問令牌字符串並在連續啟動時重新創建它。

基本上：

1. 獲得Access令牌時保存

    let strAuthenticationToken = accessToken.authenticationToken UserDefaults.standard.set(strAuthenticationToken, forKey: "AccessToken_Facebook") 

2. 獲取訪問令牌字符串並在下次啟動時重新創建AccessToken對象

    if let strAuthenticationToken = UserDefaults.standard.string(forKey: "AccessToken_Facebook") { //Create AccessToken for facebook login let accessToken = AccessToken(authenticationToken: strAuthenticationToken) //...Skip Login and directly proceed to get facebook profile data with the AccessToken } 

注意：為了便於此示例，Facebook Access令牌字符串正在保存到UserDefaults但理想情況下應將其保存到Keychain。

---

在示例中：

func loginWithFacebook() {
    //Check for previous Access Token
    if let accessToken  = AccessToken.current {
        //AccessToken was obtained during same session
        getAccountDetails(withAccessToken: accessToken)
    }
    else if let strAuthenticationToken = UserDefaults.standard.string(forKey: "AccessToken_Facebook") {
        //A previous access token string was saved so create the required AccessToken object
        let accessToken = AccessToken(authenticationToken: strAuthenticationToken)

        //Skip Login and directly proceed to get facebook profile data with an AccessToken
        getAccountDetails(withAccessToken: accessToken)
    }
    else {
        //Access Token was not available so do the normal login flow to obtain the Access Token
        doFacebookLogin()
    }
}

---

func doFacebookLogin() {
    LoginManager().logIn(readPermissions: [.publicProfile, .email], viewController: nil) { loginResult in
        switch loginResult {
        case .failed(let error):
            print(error)

        case .cancelled:
            print("User cancelled login.")

        case .success(let grantedPermissions,
                      let declinedPermissions,
                      let accessToken):

            //Save Access Token string for silent login purpose later
            let strAuthenticationToken = accessToken.authenticationToken
            UserDefaults.standard.set(strAuthenticationToken,
                                      forKey: "AccessToken_Facebook")

            //Proceed to get facebook profile data
            self.getAccountDetails(withAccessToken: accessToken)
        }
    }
}

---

func getAccountDetails(withAccessToken accessToken: AccessToken) {
    let graphRequest: GraphRequest = GraphRequest(graphPath     : "me",
                                                  parameters    : ["fields" : "id, name, email"],
                                                  accessToken   : accessToken,
                                                  httpMethod    : GraphRequestHTTPMethod.GET,
                                                  apiVersion    : GraphAPIVersion.defaultVersion)
    graphRequest.start { (response, result) in
        switch result {
        case .success(let resultResponse):
            print(resultResponse)
        case .failed(let error):
            print(error)
        }
    }
}

（Swift 4 / Facebook SDK 4.30）