Android Dropbox API - Cannot save user token after successfull authentication

Question

I am trying to connect my Android 4+ to Dropbox. I am using the latest version of the Core API provided by Dropbox.

Everything works fine until I try to save the user key and token when the user returns to my app after he authenticated the access using dropboxAPI.getSession().startOAuth2Authentication(activity) .

When the user returns to my app after the authentication the following code should save key and token:

public boolean completeLogInAfterAuthentication() {
    AndroidAuthSession session = dropboxAPI.getSession();
    if (session.authenticationSuccessful()) {
        try {
            // Mandatory call to complete the auth
            session.finishAuthentication();

            // Store it locally in our app for later use
            TokenPair tokens = session.getAccessTokenPair();
            saveSessionKeys(tokens.key, tokens.secret);
            return true;
        } catch (IllegalStateExceptione) {
            Log.d("MyLog", "Couldn't authenticate with Dropbox:" + e.getLocalizedMessage());
            Log.d("MyLog", "Error authenticating", e);
        }
    }
    return false;
}

This is quite exactly the code that is used in the DBRoulett Demo provided by Dropbox. Problem is, that session.getAccessTokenPair() returns null .

Because of this I cannot store any key or token and the user has to re-login everytime the app is started. How can I solve this?

All information I found just say, that getAccessTokenPair() could fail with an IllegalStateException but this is not the case here. The case that null is returned is not described anywhere. Any idea what I can do?

Answer 1

getAccessTokenPair is used to get an OAuth 1 access token (and secret). But you used OAuth 2, so you want getOAuth2AccessToken . From the tutorial ( https://www.dropbox.com/developers/core/start/android ):

protected void onResume() {
    super.onResume();

    if (mDBApi.getSession().authenticationSuccessful()) {
        try {
            // Required to complete auth, sets the access token on the session
            mDBApi.getSession().finishAuthentication();

            String accessToken = mDBApi.getSession().getOAuth2AccessToken();
        } catch (IllegalStateException e) {
            Log.i("DbAuthLog", "Error authenticating", e);
        }
    }
}

This is roughly the same thing that's in the DBRoulette sample, though it has code for both OAuth 1 and OAuth 2:

private void storeAuth(AndroidAuthSession session) {
    // Store the OAuth 2 access token, if there is one.
    String oauth2AccessToken = session.getOAuth2AccessToken();
    if (oauth2AccessToken != null) {
        SharedPreferences prefs = getSharedPreferences(ACCOUNT_PREFS_NAME, 0);
        Editor edit = prefs.edit();
        edit.putString(ACCESS_KEY_NAME, "oauth2:");
        edit.putString(ACCESS_SECRET_NAME, oauth2AccessToken);
        edit.commit();
        return;
    }
    // Store the OAuth 1 access token, if there is one.  This is only necessary if
    // you're still using OAuth 1.
    AccessTokenPair oauth1AccessToken = session.getAccessTokenPair();
    if (oauth1AccessToken != null) {
        SharedPreferences prefs = getSharedPreferences(ACCOUNT_PREFS_NAME, 0);
        Editor edit = prefs.edit();
        edit.putString(ACCESS_KEY_NAME, oauth1AccessToken.key);
        edit.putString(ACCESS_SECRET_NAME, oauth1AccessToken.secret);
        edit.commit();
        return;
    }
}