How to get the User detail through facebook in Android Studio..

Creating Facebook App.
Go to https://developers.facebook.com/.

First we need to add Volley Library to our project.
compile 'com.facebook.android:facebook-android-sdk:4.0.0'

Creating New Project.
Open android studio and create a new project.

File => New => New Project => Configure your new project => Select the form factor yours app will run on => Add an Activity to Mobile => Customize the Activity => Finish.
Create Xml file in project.   
Open => app => res => layout - activity_main.xml.

<com.facebook.login.widget.LoginButton
                android:id="@+id/login_button"
                android:layout_width="match_parent"
                android:layout_height="40dp"
                android:layout_marginBottom="24dp"
                android:background="@drawable/bt_facebook"
                android:padding="12dp"
                android:layout_marginTop="12dp"
                />

Create the Java file in project.
Open app => main => src = MainActivity.java

    private CallbackManager callbackManager;
    LoginButton login_button;
    String email,name,first_name,last_name;

        //*******savedInstanceState******//
        FacebookSdk.sdkInitialize(this.getApplicationContext());
        callbackManager = CallbackManager.Factory.create();
        //***put the facebookSDK and callbackManager Object in middle saveInstanceState and setContentView*****//
    


login_button=(LoginButton) findViewById(R.id.login_button);
        login_button.setReadPermissions(Arrays.asList("public_profile","email"));
        login_button.registerCallback(callbackManager, new FacebookCallback<LoginResult>()
        {
            @Override
            public void onSuccess(LoginResult loginResult)
            {

                GraphRequest graphRequest  = GraphRequest.newMeRequest(loginResult.getAccessToken(), new GraphRequest.GraphJSONObjectCallback()
                {
                    @Override
                    public void onCompleted(JSONObject object, GraphResponse response)
                    {
                        sendData(object);
                    }
                });

                Bundle parameters = new Bundle();
                parameters.putString("fields", "id,name,first_name,last_name,email");
                graphRequest.setParameters(parameters);
                graphRequest.executeAsync();
            }

            @Override
            public void onCancel()
            {

            }

            @Override
            public void onError(FacebookException exception)
            {

            }
        });

    }

    private void sendData(JSONObject object) {
        try {
            email = object.getString("email");
            name = object.getString("name");
            first_name = object.optString("first_name");
            last_name = object.optString("last_name");
        } catch (JSONException e) {
            e.printStackTrace();
        }

        Intent main = new Intent(MainActivity.this, YourActivity.class);
        main.putExtra("email", email);
        main.putExtra("name", name);
        startActivity(main);
    }


    @Override
    protected void onRestart() {
        LoginManager.getInstance().logOut();
        super.onRestart();
    }

    @Override
    protected void onResume() {
        LoginManager.getInstance().logOut();
        super.onResume();
    }

   @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent intent)
    {
        super.onActivityResult(requestCode, resultCode, intent);
        callbackManager.onActivityResult(requestCode, resultCode, intent);
      
    }
Add Internet permission in your manifest.
<uses-permission android:name="android.permission.INTERNET" />