Android Facebook SDK: OnSuccess called, but OnCancel not called

Question

I have implemented facebook login for my application. After a successful login, the onSuccess () callback is called. However, when I log out of Facebook, the onCancel () callback is not called, although the logout was completed successfully. In the logs, I see the following line after clicking on exit:

01-24 17:22:07.801 952-952/? W/SurfaceFlinger: couldn't log to binary event log: overflow 

I am using API 23. I tried it on an emulator with Android 6.0 and Facebook SDK 4.6.0 Below is my code:

 package com.example.ankur.pollutionandweathermonitor; import android.Manifest; import android.content.Intent; import android.content.pm.PackageManager; import android.os.Bundle; import android.support.v4.app.ActivityCompat; import android.support.v4.content.ContextCompat; import android.support.v7.app.AppCompatActivity; import android.support.v7.widget.Toolbar; import android.util.Log; import android.view.Menu; import android.view.MenuItem; import android.widget.Toast; import com.facebook.AccessToken; import com.facebook.CallbackManager; import com.facebook.FacebookCallback; import com.facebook.FacebookException; import com.facebook.FacebookSdk; import com.facebook.Profile; import com.facebook.login.LoginResult; import com.facebook.login.widget.LoginButton; public class MainActivity extends AppCompatActivity { //LoginButton and callbackManager are for facebook login private LoginButton loginButton; CallbackManager callbackManager; /*firstName is to store the firstname of the logged in facebook user*/ private String firstName; /*profile and accessToken are for to get the current session tokens of the logged in users*/ private Profile profile; private AccessToken accessToken; /*permissionStatus is to store the ACCESS_FINE_LOCATION permission of the user*/ private boolean permissionStatus; /*EXTRA_MESSAGE_FIRSTNAME is to send the firstname of the logged in facebook user in the intent*/ public final static String EXTRA_MESSAGE_FIRSTNAME = "USERNAME"; /*EXTRA_MESSAGE_LOCATION_PERMISSION is to send the ACCESS_FINE_LOCATION permission value in the intent*/ public final static String EXTRA_MESSAGE_LOCATION_PERMISSION = "PERMISSION"; /*Logs generated in this class are accessed through the Tag LOGTAG*/ private String LOGTAG = MainActivity.class.getSimpleName(); @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); //Initialize the facebook SDK for login FacebookSdk.sdkInitialize(getApplicationContext()); callbackManager = CallbackManager.Factory.create(); setContentView(R.layout.activity_main); //Call the CheckFacebookToken() function to see if there is a logged in user already. //The function returns the firstname if there is a logged in user, else returns null firstName = CheckFacebookToken(); if(firstName != null) { //If there is an active current Session, then check if the user has granted the // ACCESS_FINE_LOCATION permission. This check is only for Android >= 6.0 //For Android <6, the permission can be put in the AndroidMenifestFile CheckLocationPermission(); } //create the facebook login Button loginButton = (LoginButton) findViewById(R.id.login_button); try{ loginButton.setReadPermissions("user_friends"); loginButton.registerCallback(callbackManager, new FacebookCallback<LoginResult>() { @Override public void onSuccess(LoginResult loginResult) { Log.v(LOGTAG, "successfully connected to facebook"); //After the login is successful, get the firstname of the logged in user firstName = CheckFacebookToken(); //If there is an active current Session, then check if the user has granted the // ACCESS_FINE_LOCATION permission. This check is only for Android >= 6.0 //For Android <6, the permission can be put in the AndroidMenifestFile CheckLocationPermission(); } @Override public void onCancel() { someCallback(); Log.v(LOGTAG, " connection to facebook cancelled"); } @Override public void onError(FacebookException exception) { Toast.makeText(getApplicationContext(), "Fb Login Error", Toast.LENGTH_LONG); Log.v(LOGTAG, "Error on connection to facebook"); } }); }catch (Exception e){ Log.v(LOGTAG, "Error in the loginButton facebook"); e.printStackTrace(); } Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar); setSupportActionBar(toolbar); } //check if the user has granted the ACCESS_FINE_LOCATION permission. // This check is only for Android >= 6.0. For Android <6, the permission can be put in the AndroidMenifestFile protected void CheckLocationPermission(){ if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED) { ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.ACCESS_FINE_LOCATION}, 100); } else{ //Redirects the user to the Activity DisplayInformation RedirectToDisplayInformation(); } } protected void someCallback(){ Log.v(LOGTAG, "logged out from facebook"); } //The function CheckFacebookToken returns the firstname of the logged in facebook user, else returns null protected String CheckFacebookToken(){ //Check if there is an active facebook session String fName = null; try{ accessToken = AccessToken.getCurrentAccessToken(); Log.v(LOGTAG, accessToken.getToken()); } catch (Exception e){ e.printStackTrace(); } //If there is an Active facebook session, get the firstname and redirect user to the //DisplayInformation Activity, send the username through the intent if(accessToken != null) { try { profile = Profile.getCurrentProfile(); if(profile != null) { fName = profile.getFirstName(); Log.v(LOGTAG, "There is an active session. The logged in user is " + fName); } }catch (Exception e){ e.printStackTrace(); } } else { Log.v(LOGTAG, "No Active sessions found"); } return fName; } //The function RedirectToDisplayInformation redirects the user to the Activity DisplayInformation //The intent also sends the firstname of the logged in facebook user protected void RedirectToDisplayInformation(){ Log.v(LOGTAG, "successfully called the function RedirectToDisplayInformation"); Intent intent = new Intent(this, DisplayInformation.class); intent.putExtra(EXTRA_MESSAGE_LOCATION_PERMISSION, String.valueOf(permissionStatus)); intent.putExtra(EXTRA_MESSAGE_FIRSTNAME,firstName ); //startActivity(intent); } //This function is to call the callback functions of facebook after the login attempt @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { super.onActivityResult(requestCode, resultCode, data); callbackManager.onActivityResult(requestCode, resultCode, data); } @Override public boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.menu.menu_main, menu); return true; } @Override public boolean onOptionsItemSelected(MenuItem item) { // Handle action bar item clicks here. The action bar will // automatically handle clicks on the Home/Up button, so long // as you specify a parent activity in AndroidManifest.xml. int id = item.getItemId(); //noinspection SimplifiableIfStatement if (id == R.id.action_settings) { return true; } return super.onOptionsItemSelected(item); } //The function onRequestPermissionResult is a callback to promt the user to either allow or deny the //permissions. This function is significant only for Android >6 @Override public void onRequestPermissionsResult(int requestCode,String permissions[], int[] grantResults) { Log.v(LOGTAG, "onRequestPermissionResult"); switch (requestCode) { case 100: { // If request is cancelled, the result arrays are empty. if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) { permissionStatus = true; Log.v(LOGTAG, "Permission Granted. Status is: " + String.valueOf(permissionStatus)); } else { permissionStatus = false; Log.v(LOGTAG, "Permission Denied. Status is: " + String.valueOf(permissionStatus)); } RedirectToDisplayInformation(); return; } } } } 

Answer 1

FacebookCallback onCancel () is called only when the login dialog is canceled without continuing to log in.

Upon exiting the system, the profile and AccessToken will become null, but onCancel will not be called.

Hope this helps :)