Adding Color Change Logic

Right now, our three radio buttons appear in the app and let the user choose between Red, Green, and Orange, but nothing happens when you select them.

In this step, we’ll make it so that when the user clicks one of the radio buttons, the square instantly changes to that color.

We’ll do this by adding a listener to the radio button group. A listener is a little piece of code that runs whenever something changes. So in this case, when a different radio button is selected.

Set Up the Listener

The colorGroup already holds all three radio buttons. We can attach a listener to it using selectedToggleProperty().addListener(...).

Let’s break down what this is doing:

• colorGroup.selectedToggleProperty() watches the selected radio button.

• When it changes, our listener runs.

• We typecast newToggle back to a RadioButton so we can check which one it is.

• We use getText() to get the label on that button (like "Red").

• Then we use a switch statement to change the square’s color to match using setFill(...)