How to add a logout callback for facebook sdk in android

Question

I have integrated Facebook sdk in my android app. As described in the manual I added the login callback for facebook. But I have to change the UI if the user logs out from facebook. Where do I put that code. My code for login is

         /**
         * Login Callback for facebook login
         */
        callbackManager = CallbackManager.Factory.create();

    LoginManager.getInstance().registerCallback(callbackManager,
            new FacebookCallback<LoginResult>() {

                @Override
                public void onSuccess(LoginResult loginResult) {
                    //Call updateUI()

                    setData("provider","facebook");
                    loginType = LoginTypes.FB_LOGIN;
                    isLoggedin = true;
                    GraphRequest request = GraphRequest.newMeRequest(
                            loginResult.getAccessToken(),
                            new GraphRequest.GraphJSONObjectCallback() {
                                @Override
                                public void onCompleted(
                                        JSONObject object,
                                        GraphResponse response) {
                                    // Application code

                                    txtName.setText(response.toString());
                                    updateUI();
                                }
                            });
                    Bundle parameters = new Bundle();
                    parameters.putString("fields", "id,name,email");
                    request.setParameters(parameters);
                    request.executeAsync();
                }

                @Override
                public void onCancel() {
                    editText_message.setText("Login Cancelled.");
                    // App code
                }

                @Override
                public void onError(FacebookException exception) {
                    // App code
                }
            });

Answer 1

there are 2 possible ways:

1) you need to overwrite in on create AccessTokenTracker like this:

accessTokenTracker = new AccessTokenTracker() {
            @Override
            protected void onCurrentAccessTokenChanged(AccessToken oldAccessToken,
                                                       AccessToken currentAccessToken) {
                    if (currentAccessToken == null) {
                        //write your code here what to do when user logout
                    } 
                }
            }

2) You can call LoginManager.logOut() to log out the user

hope this will help you :)