Re-Login using Facebook SDK in Android Application

Hello,

Android applications often require login to identify the user and provide user specific content. Facebook login is one of the popular SDK used to authenticate users.

In this post I will share the code to smoothly re-login the user using Facebook SDK.

Following is complete Login class which can be used for Facebook Login

public class DemoLoginActivity extends AppCompatActivity {
    LoginButton loginButton;
    CallbackManager callbackManager;

    FacebookCallback<LoginResult> loginResultFacebookCallback = new FacebookCallback<LoginResult>() {
        @Override
        public void onSuccess(final LoginResult loginResult) {
            GraphRequest request = GraphRequest.newMeRequest(
                    loginResult.getAccessToken(),
                    new GraphRequest.GraphJSONObjectCallback() {
                        @Override
                        public void onCompleted(
                                JSONObject object,
                                GraphResponse response) {
                        }
                    });
            Bundle parameters = new Bundle();
            parameters.putString("fields", "id, name, picture,email");
            request.setParameters(parameters);
            request.executeAsync();
        }

        @Override
        public void onCancel() {
        }

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

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        FacebookSdk.sdkInitialize(getApplicationContext());
        setContentView(R.layout.loginflow);
        loginButton = (LoginButton) findViewById(R.id.facebook_button);
        List<String> permissions = new ArrayList<>();
        permissions.add("email");
        loginButton.setReadPermissions(permissions);
        callbackManager = CallbackManager.Factory.create();
        loginButton.registerCallback(callbackManager, loginResultFacebookCallback);
        LoginManager.getInstance().registerCallback(callbackManager, loginResultFacebookCallback);

        AccessToken accessToken = AccessToken.getCurrentAccessToken();
        if (accessToken != null) {
            if (accessToken.isExpired()) {
                LoginManager.getInstance().logOut();
            } else {
                /// This is code responsible for re-login
                LoginManager.getInstance().logInWithReadPermissions(this, permissions);
            }
        }
    }

    protected void onActivityResult(int requestCode, int responseCode,
                                    Intent intent) {

        super.onActivityResult(requestCode, responseCode, intent);
        callbackManager.onActivityResult(requestCode, responseCode, intent);
    }

}

Hope this helps. Happy coding :)

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Keep visiting and sharing.
Thanks,
Ashwani.