Code For Facebook Login

main
=========
CallbackManager callbackManager;
    ProgressDialog mdialog;
    TextView txtEmail, txtName;


    RelativeLayout login;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);
        setPointer();
    }

    private void setPointer() {
        login =  findViewById(R.id.login);

        login.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(main.this,MainActivity.class);
                startActivity(intent);
            }

        });
        // For Facebook Login
        callbackManager = CallbackManager.Factory.create();
        txtEmail = findViewById(R.id.txtEmail);
        txtName = findViewById(R.id.txtName);

        @SuppressLint("WrongViewCast") LoginButton loginButton = (LoginButton) findViewById(R.id.login_button);
        loginButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

            }
        });
        loginButton.setReadPermissions(Arrays.asList("email","public_profile"));
        loginButton.registerCallback(callbackManager, new FacebookCallback<LoginResult>() {
            @Override
            public void onSuccess(LoginResult loginResult) {
                mdialog = new ProgressDialog(main.this);
                mdialog.setMessage("Retrieving data...");
                mdialog.show();
                String accesstoken = loginResult.getAccessToken().getToken();

                GraphRequest request = GraphRequest.newMeRequest(loginResult.getAccessToken(), new GraphRequest.GraphJSONObjectCallback() {
                    @Override
                    public void onCompleted(JSONObject object, GraphResponse response) {
                        mdialog.dismiss();
                        Log.d("response",response.toString());
                        getData(object);
                    }
                });
                Bundle parameters = new Bundle();
                parameters.putString("fields","id,email,birthday,friends,name");

                request.setParameters(parameters);
                request.executeAsync();

            }
            @Override
            public void onCancel() {
            }

            @Override
            public void onError(FacebookException error) {

            }
        });

        // if already login
        if (AccessToken.getCurrentAccessToken() != null){

            // Just set user Id
            txtEmail.setText(AccessToken.getCurrentAccessToken().getUserId());
        }

    }
    @Override

    // Facebook Methods
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        callbackManager.onActivityResult(requestCode, resultCode, data);
    }
    public void getData(JSONObject object) {

        try {
            //   URL profile_picture = new URL("https://graph.facebook.com/" + object.getString("id") + "/picture?width=250&height=250");
            //   Picasso.with(this).load(profile_picture.toString()).into(imgAvatar);
            txtEmail.setText(object.getString("email"));
            //   txtBirthday.setText(object.getString("birthday"));
            //   txtFriends.setText("Friends: " + object.getJSONObject("friends").getJSONObject("summary").getString("total_count"));
               txtName.setText(object.getString("name"));

        } catch (JSONException e) {
            e.printStackTrace();
        }


    }
    // End of Facebook Method
}
========================================================================================================


Manifest
==============
<meta-data
            android:name="com.facebook.sdk.ApplicationId"
            android:value="@string/facebook_app_id" />



==========================================================================================================



app.gruild(Module:app)
========================
implementation 'com.facebook.android:facebook-android-sdk:4.28.0'




===========================================================================================================



string.xml
=============
<!-- Facebook Codes to make facebook login -->
    <string name="facebook_app_id">1541145485955161</string>
    <string name="fb_login_protocol_scheme">fb1541145485955161</string>


============================================================================================================


activity_main.xml
=================

<android.support.design.widget.TabLayout
            android:id="@+id/tabs"
            android:layout_width="match_parent"
            android:layout_height="42dp"
            android:background="#D1C4E9"
            app:tabSelectedTextColor="#6200EA"
            app:tabTextAppearance="@android:style/TextAppearance.Widget.TabWidget"
            app:tabTextColor="#6200EA"
            app:tabGravity="fill"


==================================================================================================