android - Profile.getCurrentProfile() returns null after logging in (FB API v4.0)

Question

For some reason Profile.getCurrentProfile() shows up null at times right after logging into FaceBook, using FB API v4.0.

This is causing problems for me in my app because I can't display my next Activity with Profile being null.

The reason I say it's null sometimes is because if I close out of my app and re-open it, I'm able to get to my next Activity, but if I'm not already logged in, and then login, Profile is null. It seems it is for a short period.

Is there a work around or fix to this?

Answer 1

Like Hardy said, you have to create an instance of ProfileTracker which will start tracking profile updates, (i.e ProfileTracker.onCurrentProfileChanged() will be called when the user's profile finishes being fetched).

Following is the complete code that you'd need to login to FB and get the user's profile:

LoginButton loginButton = (LoginButton) findViewById(R.id.btn_facebook);
loginButton.setReadPermissions("public_profile");
mCallbackManager = CallbackManager.Factory.create();
loginButton.registerCallback(mCallbackManager, new FacebookCallback<LoginResult>() {

    private ProfileTracker mProfileTracker;

    @Override
    public void onSuccess(LoginResult loginResult) {
        if(Profile.getCurrentProfile() == null) {
            mProfileTracker = new ProfileTracker() {
                @Override
                protected void onCurrentProfileChanged(Profile oldProfile, Profile currentProfile) {
                    Log.v("facebook - profile", currentProfile.getFirstName());
                    mProfileTracker.stopTracking();
                }
            };
            // no need to call startTracking() on mProfileTracker
            // because it is called by its constructor, internally.
        }
        else {
            Profile profile = Profile.getCurrentProfile();
            Log.v("facebook - profile", profile.getFirstName());
        }
    }

    @Override
    public void onCancel() {
        Log.v("facebook - onCancel", "cancelled");
    }

    @Override
    public void onError(FacebookException e) {
        Log.v("facebook - onError", e.getMessage());
    }
});

You must override your Activity's or Fragment's onActivityResult() as below:

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    // if you don't add following block,
    // your registered `FacebookCallback` won't be called
    if (mCallbackManager.onActivityResult(requestCode, resultCode, data)) {
        return;
    }
}

Edit:

Code updated with Alex Zezekalo's suggestion to only call mProfileTracker.startTracking(); if Profile.getCurrentProfile() returns null.