Facebook android SDK重新打开会话

Question

I am developing a facebook-integrated application and i am experiencing a very weird issue.

I log in normally, but as i am about to log out the SDK forces a login again...

package com.machinarius.facebook;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.LinkedList;
import java.util.List;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

import com.facebook.Request;
import com.facebook.Request.GraphUserCallback;
import com.facebook.Response;
import com.facebook.Session;
import com.facebook.Session.NewPermissionsRequest;
import com.facebook.Session.StatusCallback;
import com.facebook.SessionState;
import com.facebook.model.GraphUser;

public class MainActivity extends Activity implements StatusCallback, GraphUserCallback {
    private TextView statusText;
    private Button loginButton;
    private Boolean loggedIn;
    private Session actualSession;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        loggedIn = false;
        statusText = (TextView)findViewById(R.id.statusText);
        loginButton = (Button)findViewById(R.id.loginButton);
    }

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

    public void toggleFacebookLogin(View source) {
        if(!loggedIn) {
            actualSession = Session.openActiveSession(this, true, this);
        }
        else 
            if(actualSession == null)
                return;
            else {
                actualSession.close();
                statusText.setText("Please login");
                loggedIn = false;
            }
    }

    @Override
    public void call(Session session, SessionState state, Exception exception) {
        if(state.equals(SessionState.OPENED)) {
            loggedIn = true;
            List<String> permissions = getNewPermissions(actualSession.getPermissions(), 
                    new LinkedList<String>(Arrays.asList("user_about_me", "user_birthday", "user_hometown", "user_relationships", "user_location", "user_relationships", "email")));
            Session.NewPermissionsRequest permissionsRequest = new NewPermissionsRequest(this, permissions);
            actualSession.requestNewReadPermissions(permissionsRequest);
            populateInterface();
        } else {
            loggedIn = false;
        }
    }

    private void populateInterface() {
        Request.executeMeRequestAsync(Session.getActiveSession(), this);
    }

    @Override
    public void onCompleted(GraphUser user, Response response) {
        if(response.getError() != null) {
            statusText.setText("There was an error fetching your info");
            Log.e(getClass().getName(), response.getError().toString());
            return;
        }
        if(user != null) {
            statusText.setText("Hello " + user.getName() + "\n"
                    + "Your user ID is " + user.getId() + "\n"
                    + "Your birthday is " + user.getBirthday());
            loginButton.setText("Log out");
        } else {
            statusText.setText("There was an error fetching your info");
        }
    }

    private List<String> getNewPermissions(List<String> actualPermissions, List<String> desiredPermissions) {
        ArrayList<String> permissionsGranted = new ArrayList<String>();
        for(String nPermission : desiredPermissions)
            for(String aPermission : actualPermissions)
                if(nPermission.equals(aPermission))
                    permissionsGranted.add(nPermission);
        for(String gPermission : permissionsGranted)
            desiredPermissions.remove(gPermission);
        return desiredPermissions;
    }
}

toggleFacebookLogin is called by a XML onClick handler on the loginButton.

Another question as well, how can i integrate the permissions request into the session.open call so i dont have to make the user see a facebook dialog twice?

Answer 1

The problem here is that you're only checking for

state.equals(SessionState.OPENED)

in your call method rather than

state.isOpened()

So when you request additional permissions, the state actually transitions to OPENED_TOKEN_UPDATED, and now your loggedIn state is false (even though it should be true). So when you click the button, you're calling openActiveSession again because your loggedIn state is incorrect. If you switch to checking state.isOpened() , it should fix your issue.

To answer your second question, since you're only requesting read permissions, you can request them all at once when you open the session (whereas if you also wanted to request publish permissions - like publish_stream, then you'd need to separate the requests). To do it all at once, you need to replace your Session.openActiveSession(this, true, this) with something like:

Session actualSession = new Session(this);
Session.setActiveSession(actualSession);
actualSession.openForRead(new Session.OpenRequest(this).setPermissions(Arrays.asList("some", "read", "permissions")).setCallback(this));

Note: I wrote the above off the top of my head, so there might be syntax errors.