如何在活动之间处理 Facebook Android SDK v4.1 访问令牌

Question

当我在成功登录用户后转到另一个 activity 时，我无法访问 Facebook 访问令牌

AccessToken.getCurrentAccessToken()

我在 LogCat 中得到了这个：

{AccessToken token:ACCESS_TOKEN_REMOVED permissions:[]}

Answer 1

如果您使用 android 登录按钮，我的解决方案是： 要使用片段并在每个 activity 中调用它，您可以根据当前 activity 将要做什么来选择是否显示它，片段的所有方法都可以正常工作。

这是一些代码：

package com.infoplusplus.anix.currentapp;

import android.content.Intent;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import com.facebook.AccessToken;
import com.facebook.AccessTokenTracker;
import com.facebook.CallbackManager;
import com.facebook.FacebookCallback;
import com.facebook.FacebookException;
import com.facebook.FacebookSdk;
import com.facebook.Profile;
import com.facebook.ProfileTracker;
import com.facebook.login.LoginResult;
import com.facebook.login.widget.LoginButton;


/**
 * Created by Anix on 09/04/2015.
 */
public class LoginFacebookFragment extends Fragment {
    public LoginFacebookFragment() {
    }

    private ProfileTracker profileTracker;
    private AccessTokenTracker tokenTracker;
    private LoginButton loginButton;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        FacebookSdk.sdkInitialize(getActivity().getApplicationContext());
        mCallbackManager = CallbackManager.Factory.create();
        tokenTracker = new AccessTokenTracker() {
            @Override
            protected void onCurrentAccessTokenChanged(AccessToken oldToken, AccessToken newToken) {
            }
        };
        profileTracker = new ProfileTracker() {
            @Override
            protected void onCurrentProfileChanged(Profile oldProfile, Profile newProfile) {
                if (newProfile != null) {
                    //TODO the user has logged out
                } else {
                   //TODO the user may have logged in or changed some of his profile settings
                }
            }
        };
        profileTracker.startTracking();
        tokenTracker.startTracking();
    }

    @Override
    public View onCreateView(LayoutInflater inflater,
                             ViewGroup container,
                             Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.fragment_login_facebook, container, false);
        return rootView;
    }

    private CallbackManager mCallbackManager;
    private FacebookCallback<LoginResult> mCallback = new FacebookCallback<LoginResult>() {
        @Override
        public void onSuccess(LoginResult loginResult) {
            //TODO, implement onSuccess
        }

        @Override
        public void onCancel() {
            //TODO, implement onCancel
        }

        @Override
        public void onError(FacebookException e) {
            //TODO, implement onError inorder to handle the errors
        }
    };

    @Override
    public void onViewCreated(View view, Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        loginButton = (LoginButton) view.findViewById(R.id.btn_facebookLogin);
        //TODO: get some more permissions from the user
        //loginButton.setReadPermissions("user_friends");
        loginButton.setFragment(this);
        loginButton.registerCallback(mCallbackManager, mCallback);
    }

    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        mCallbackManager.onActivityResult(requestCode, resultCode, data);
    }

    @Override
    public void onResume() {
        super.onResume();
        profileTracker.startTracking();
        tokenTracker.startTracking();
    }

    @Override
    public void onPause() {
        super.onPause();
        profileTracker.stopTracking();
        tokenTracker.stopTracking();
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        tokenTracker.stopTracking();
        profileTracker.stopTracking();
    }
}