Elgallati Noreddine Elgallati Noreddine - 1 year ago 123
Android Question

why setReadPermissions is rendering NullPointerException in Facebook login in android studio

i am trying to integrate Facebook login into my app but when i try to enter to the activity when my button is.

I followed this tutorial: http://alvarez.tech/login-facebook-en-android/

my activity is like:

public void onCreate(Bundle savedInstanceState) {

if(savedInstanceState!= null) return;

FrameLayout frameLayout = (FrameLayout)findViewById(R.id.fragment_container);

connexion0 = new connexion0Fragment();
connexion1 = new connexion1Fragment();



public void connexionViaFacebook(){
callbackManager = CallbackManager.Factory.create();

loginButton = (LoginButton) findViewById(R.id.loginButton);


loginButton.registerCallback(callbackManager, new FacebookCallback<LoginResult>() {
public void onSuccess(LoginResult loginResult) {

public void onCancel() {
Toast.makeText(getApplicationContext(), R.string.cancel_login, Toast.LENGTH_SHORT).show();

public void onError(FacebookException error) {
Toast.makeText(getApplicationContext(), R.string.error_login, Toast.LENGTH_SHORT).show();

the error is:

java.lang.NullPointerException: Attempt to invoke virtual method 'void com.facebook.login.widget.LoginButton.setReadPermissions(java.util.List)' on a null object reference

Answer Source

I think you have forgot to add the facebook initialization code in the oncreate() method of your main activity. FacebookSdk.sdkInitialize(getApplicationContext());

In your reference link, the initialization part has been done in the class extending Application.


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