Android - 清除Facebook访问令牌

Question

我有一个SettingsActivity地方有几个选项,包括寻找Facebook好友和退出.因此,当用户选择找到她的Facebook好友时,她将被发送到另一个活动,我让她使用她的Facebook帐户登录并保存她的访问令牌.然后,当她选择退出时,她的访问令牌将被清除.问题是,我的logout方法与我创建会话的方法没有写在同一个活动中,所以当我尝试这个时:

    Session session = Session.getActiveSession();
    if (!session.isClosed()) {
        session.closeAndClearTokenInformation();
    }

Logcat积分NullPointerException.然后我尝试了:

Session.setActiveSession(null);

这也不起作用(之前登录的用户的朋友仍然显示,而不是要求新用户登录).

那么我该怎么做才能清除获得的令牌呢？先感谢您.

-编辑-

我认为我用来打开会话的活动有问题.我关注了Facebook的GraphAPISample,这就是我所做的:

public class FacebookFriendsActivity extends FragmentActivity{
    private BroadcastReceiver broadcast;
    public static Session session;
    private boolean pendingRequest;
    static final String PENDING_REQUEST_BUNDLE_KEY = "PendingRequest";

    private DatabaseHandler db;
    private FindFacebookFriends task;
    private ProgressBar progress;
    private TextView text;
    private Button retryBtn;
    private ListView userLayout;
    private ArrayList<User> userList;
    private FollowAdapter adapter;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.facebook_friends);
        // ... set views 

        session = createSession();
        Settings.addLoggingBehavior(LoggingBehavior.INCLUDE_ACCESS_TOKENS);

        showFriends();
    }

    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        if (session.onActivityResult(this, requestCode, resultCode, data) &&
                pendingRequest &&
                session.getState().isOpened()) {
            showFriends();
        }
    }

    @Override
    protected void onRestoreInstanceState(Bundle savedInstanceState) {
        super.onRestoreInstanceState(savedInstanceState);

        pendingRequest = savedInstanceState.getBoolean(PENDING_REQUEST_BUNDLE_KEY, pendingRequest);
    }

    @Override
    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);

        outState.putBoolean(PENDING_REQUEST_BUNDLE_KEY, pendingRequest);
    }

    private void showFriends(){
        task = new FindFacebookFriends();
        task.execute(session.getAccessToken());

    }

    private Session createSession() {
        Session activeSession = Session.getActiveSession();
        if (activeSession == null || activeSession.getState().isClosed()) {
            activeSession = new Session.Builder(this).setApplicationId(getString(R.string.fb_app_id)).build();
            Session.setActiveSession(activeSession);
            new SaveFacebookId().execute(activeSession.getAccessToken());
        }

        return activeSession;
    }
}

当我尝试Toast输入createSession()以检查创建的状态时activeSession,它始终显示会话已关闭.这很奇怪,因为该showFriends()方法仍然被触发,即使我再次删除并安装应用程序后,它仍然显示相同的朋友列表.我真的很困惑.

Answer 1

在Facebook SDK v4中我们可以使用注销

LoginManager.getInstance().logOut();

请注意,不要忘记像这样初始化sdk

FacebookSdk.sdkInitialize(getApplicationContext());