How to Select an Item by Default in JavaFX

In this article, we show how to select an item by default in JavaFX.

This applies to items such as radio buttons, check boxes, list views, etc.

If you create a group of radio buttons or a group of check boxes, unless you add code specifically to select an item by default, none of the buttons or boxes will be selected. All are unselected.

However, you can add code that selects one radio button by default (since only one can be selected) or 1 or more check boxes.

Let's say we have a radio button named radiobutton1. To select this radio button by default, we would use the setSelected(true) statement. This is shown below.

radiobutton1.setSelected(true);

So basically we use the setSelected() function and pass in the parameter true to this function. This selects radiobutton1 by default, so that when the window comes up with the radio buttons, the radiobutton1 is automatically selected in the options.

This same thing is done for check boxes. However, with check boxes, unlike with radio buttons, you can select multiple options by default. So, let's you have 2 check boxes, checkbox3 and checkbox5.

To select these check boxes by default, the following code can be used.

checkbox3.setSelected(true); checkbox5.setSelected(true);

If you pass in false to this setSelected() function, then it's the equivalent to putting in no code at all. The item will not be selected by default.

Below is the full Java code that creates a group of radio buttons and by default selects the first radio button.

import javafx.application.Application; import javafx.scene.Scene; import javafx.scene.control.Button; import javafx.scene.control.Label; import javafx.scene.control.RadioButton; import javafx.scene.control.ToggleGroup; import javafx.scene.layout.VBox; import javafx.stage.Stage; public class Quiz extends Application { static String result; @Override public void start(Stage primaryStage) { primaryStage.setTitle("Quiz Question 1"); Label labelfirst= new Label("What is 10 + 20?"); Label labelresponse= new Label(); VBox layout= new VBox(5); Button button= new Button("Submit"); RadioButton radio1, radio2, radio3, radio4; radio1=new RadioButton("10"); radio2= new RadioButton("20"); radio3= new RadioButton("30"); radio4= new RadioButton("40"); ToggleGroup question1= new ToggleGroup(); radio1.setToggleGroup(question1); radio2.setToggleGroup(question1); radio3.setToggleGroup(question1); radio4.setToggleGroup(question1); radio1.setSelected(true); button.setOnAction(e -> { if (radio3.isSelected()) { labelresponse.setText("Correct answer"); } else { labelresponse.setText("Wrong answer"); } } ); layout.getChildren().addAll(labelfirst, radio1, radio2, radio3, radio4, button, labelresponse); Scene scene1= new Scene(layout, 400, 250); primaryStage.setScene(scene1); primaryStage.show(); } public static void main(String[] args) { launch(args); } }

So this is just the full code so that you can see the radio button group created. There are 4 radio buttons in the group, simulating 4 answer options for the quiz question. These radio buttons are radio1, radio2, radio3, and radio4.

The line, radio1.setSelected(true);, allows us to select the first radio button by default.

Running the above code produces the image at the following link: Radio Button Selected By Default.

And this is all that is required to select an item by default in JavaFX.

Related Resources

How to Add a Title to a Window Using JavaFX