Facebook SDK 4 for Android - how to log out programmatically

Question

You can use LoginManager.getInstance().logOut();, even if you use LoginButton because

This UI element wraps functionality available in the LoginManager.

EDIT: Just to mention that this works for Facebook SDK v4. I don't know if they will change it in the future.

@as batoutofhell mention, don't forget to put FacebookSdk.sdkInitialize(getApplicationContext()); to initialize the facebook sdk. Please see here for the details.

SDK4, if you want to completely de-couple, make sure you also remove the app from the user's facebook account. This method disconnects the user completely:

public void disconnectFromFacebook() {

    if (AccessToken.getCurrentAccessToken() == null) {
        return; // already logged out
    }

    new GraphRequest(AccessToken.getCurrentAccessToken(), "/me/permissions/", null, HttpMethod.DELETE, new GraphRequest
            .Callback() {
        @Override
        public void onCompleted(GraphResponse graphResponse) {

            LoginManager.getInstance().logOut();

        }
    }).executeAsync();
}

You can use LoginManager.logOut()

Check out https://developers.facebook.com/docs/reference/android/current/class/LoginManager/

To handle it with the loginButton:

//Check if user is currently logged in
        if (AccessToken.getCurrentAccessToken() != null && com.facebook.Profile.getCurrentProfile() != null){
            //Logged in so show the login button
            fbLogin.setVisibility(View.VISIBLE);
            fbLogin.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
//log out
                    LoginManager.getInstance().logOut();
                    gotoLogin();
                }
            });
        }

You can logout by using LoginManager but you have to use graph request also. I am talking about log out completely so, that next time you can login with different account.

new GraphRequest(AccessToken.getCurrentAccessToken(), "/me/permissions/", null, HttpMethod.DELETE, new GraphRequest
            .Callback() {
        @Override
        public void onCompleted(GraphResponse graphResponse) {

            SharedPreferences pref = DashBoard.this.getPreferences(Context.MODE_PRIVATE);
            SharedPreferences.Editor editor = pref.edit();
            editor.clear();
            editor.commit();
            LoginManager.getInstance().logOut();

            Intent logoutint = new Intent(DashBoard.this,MainActivity.class);
            logoutint.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
               startActivity(logoutint);

        }
    }).executeAsync();

By the help of shared preferences here you can logout completely, and next time you can login with different account.

Frank version kotlin:

 fun disconnectFromFacebook() {
    if (AccessToken.getCurrentAccessToken() == null) {
        return  // already logged out
    }
    GraphRequest(
        AccessToken.getCurrentAccessToken(),
        "/me/permissions/",
        null,
        HttpMethod.DELETE,
        GraphRequest.Callback {
            LoginManager.getInstance().logOut()
        }).executeAsync()
}