注册回调错误Android Facebook登录

Question

I am new to android. Currently adding facebook login to my app. It is giving errors on two occasions. 1. loginButton.setFragment(); and 2. on 'callbackManager' in loginButton.registerCallback(callbackManager, new FacebookCallback()

package com.example.mabdullahali.trenditch;
        import android.content.Intent;
        import android.os.Bundle;
        import android.app.Fragment;
        import android.view.LayoutInflater;
        import android.view.View;
        import android.view.ViewGroup;

        import com.facebook.FacebookCallback;
        import com.facebook.FacebookException;
        import com.facebook.login.LoginResult;
        import com.facebook.login.widget.LoginButton;


        /**
         * A simple {@link Fragment} subclass.
         */
        public class fragment_facebook_login extends Fragment {

            LoginButton loginButton;
            public fragment_facebook_login() {
                // Required empty public constructor
            }


            @Override
            public View onCreateView(
                    LayoutInflater inflater,
                    ViewGroup container,
                    Bundle savedInstanceState) {
                View view = inflater.inflate(R.layout.fragment_fragment_facebook_login, container, false);

                loginButton = (LoginButton) view.findViewById(R.id.login_button);
                loginButton.setReadPermissions("email");
                // If using in a fragment
                //loginButton.setFragment(this);
                // Other app specific specialization
                loginButton.setFragment();

                // Callback registration
                loginButton.registerCallback(callbackManager, new FacebookCallback<LoginResult>() {
                    @Override
                    public void onSuccess(LoginResult loginResult) {
                        // App code
                    }

                    @Override
                    public void onCancel() {
                        // App code
                    }

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




        }

Answer 1

Add the following piece of code:

callbackManager = CallbackManager.Factory.create();

to your Fragment's onCreate or onCreateView method.