Step $1$: Login Scene and LoginController.java

Login.fxml

First, open Login.fxml in SceneBuilder and design the scene. You don$$t

necessarily need to exactly match what I did, but the closer you are the easier

I will be able to help with debugging. Most of it should be straightforward but

note that the password field should be a PasswordField instead of a TextField.

The only difference is that typed letters automatically appear as $*****.$

Once the scene is laid out, make sure to set the controller to LoginController.

Then, ensure you set IDs for each of the elements listed in LoginController.

This is nameField, passwordField, and errorLabel. Also, ensure the buttons have methods listed

as events $($openSettings$()$ for $$Settings$,$ login for $$Calculator Login$).$ Once you$$re satisfied with

that, clear the text of the errorLabel so that it starts empty.

LoginController.java

login$()$: The goal is to validate the username and password and open the calculator scene if so$.$

Do this by manually checking if both the contents of nameField and passwordField match the

contents of username and password respectively. If both do$,$ call openCalculator$()$; Else, set

errorLabel to be $$Invalid login credentials.$$

Additionally, in login$(),$ put these $3$ lines immediately after calling openCalculator$().$ It closes the

login screen when loading the calculator screen.

Button caller $=($Button$)$event$.$getSource$()$;

Stage stage $=($Stage$)$caller$.$getScene$().$getWindow$()$;

stage.close$()$;

Testing: with this filled in$,$ you can now do more testing. If you run the program to the login

screen and enter $$admin$$ and $$password$$ respectively $($hardcoded values$),$ you should be able

to load the calculator. If you didn$$t in step $0,$ you may need to open Calculator.fxml in

SceneBuilder and make sure the controller is set correctly to have this

work. Clicking $$settings$$ will load an empty scene, which leads you into...

Step $2$: Settings Scene and SettingsController.java

Settings.fxml

First, open Settings.fxml in SceneBuilder and design the scene. It$$s worth

note that this screen only simulates the profile saving $$ there is no actual

saving of birthday or preferred language. The only saved part is the new

username and password if they are set. The new elements here are:

DatePicker: This element works with virtually $0$ effort. Just drag it into the scene next to a label

and it works automatically.

RadioButton: These also work mostly automatically. However, you must set the Toggle Group

property of both buttons. It doesn$$t matter what, as long as they are the same. I suggest

$$language$.$ This makes it so you can only select $1$ at a time, not both. Test this to make sure it

works before moving on$.$

Like before, set the controller to SettingsController and set the IDs and events for each element.

You need IDs for datePicker, usernameField, passwordField, radioJava, radioPython,

errorLabel, and confirmLabel. $$Update$$ should have event set to updateInfo, $$Save Profile$$

should be set to save, and $$Return to Login$$ should be set to returnToLogin. Lastly, empty the

text of errorLabel and confirmLabel.

SettingsController.java

updateInfo$()$: Let$$s start here since it only requires $4$ lines. The first $2$ should update the value of

LoginController.username and LoginController.password to be the current text of

usernameField and passwordField respectively. Next, empty errorLabel and set confirmLabel to

$$Login credentials updated.$$ Note the lack of error checking for username and password $($you

could enter both as $).$ That is an optional challenge you can try once you get the rest of the

project working :$)$

save$()$: First, as edge cases, empty both errorLabel and confirmLabel. Next, you need to check if

the user has selected a birthday and one of the preferred languages. To check if a date was

selected, you can say if$($datePicker$.$getValue$()==$ null$).$ To check the radio buttons, check if both

have not been selected $($use isSelected$()).$ Update errorLabel accordingly for either $($You didn$$t

select a birthday.$$ or $$You didn$$t select a preferred language.$)$ If neither case happens, update

confirmLabel to $$Profile saved.$$

Testing: You can now do more testing. You should be able to enter the settings screen and

update the login credentials, so make sure of this before moving on$.$ The rest of the settings

page should react accordingly based on whether you selected a date or preferred language, try

out various combinations to ensure the error$/$confirmation labels act right.

Step $3$: Calculator Scene and CalculatorController.java

Calculator.fxml

Thankfully, you don$$t have to do any work for this part :) I provided Calculator.fxml

already filled in$.$ However, you should examine the layout to ensure you understand

how it works. Each of the numbers $0-9$ is connected to numButton$(),$ the operators

have operatorButton$(),$ equals has equals$(),$ clear has clear$(),$ and $$Logout$$ has

logout$()$ already implemented. Additionally, note that the text field up to