• Creating a CheckBox
• Adding a CheckBox to the Scene Graph
• Reading Selected State
• Allowing Indeterminate State
• Reading Indeterminate State

A JavaFX CheckBox is a button which can be in three different states: Selected, not selected and unknown (indeterminate). The JavaFX CheckBox control is represented by the class javafx.scene.control.CheckBox.

Creating a CheckBox

You create a JavaFX CheckBox control via the CheckBox constructor. Here is a JavaFX CheckBox instantiation example:

CheckBox checkBox1 = new CheckBox("Green");

The String passed to the CheckBox constructor is displayed next to the CheckBox control.

Adding a CheckBox to the Scene Graph

To make a JavaFX CheckBox control visible you must add it to the scene graph of your JavaFX application. That means adding the CheckBox control to a Scene object, or to some layout component which is itself added to a Scene object.

Here is an example showing how to add a CheckBox to the scene graph:

package com.jenkov.javafx.controls;

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.CheckBox;
import javafx.scene.layout.HBox;
import javafx.stage.Stage;


public class CheckBoxExperiments extends Application  {


    @Override
    public void start(Stage primaryStage) throws Exception {
        primaryStage.setTitle("CheckBox Experiment 1");

        CheckBox checkBox1 = new CheckBox("Green");

        HBox hbox = new HBox(checkBox1);

        Scene scene = new Scene(hbox, 200, 100);
        primaryStage.setScene(scene);
        primaryStage.show();

    }

    public static void main(String[] args) {
        Application.launch(args);
    }

}

The application resulting from running this code looks like this:

Reading Selected State

You can read the selected state of a CheckBox via its method isSelected(). Here is an example of how calling isSelected() looks:

boolean isSelected = checkBox1.isSelected();

Allowing Indeterminate State

As mentioned earlier a JavaFX CheckBox can be in an indeterminate state which means that is is neither selected, nor not selected. The user simply has not interacted with the CheckBox yet.

By default a CheckBox is not allowed to be in the indeterminate state. You can set if a CheckBox is allowed to be in an indeterminate state using the method setAllowIndeterminate(). Here is an example of allowing the indeterminate state for a CheckBox:

checkBox1.setAllowIndeterminate(true);

Reading Indeterminate State

You can read if a CheckBox is in the indeterminate state via its isIndeterminate() method. Here is an example of checking if a CheckBox is in the indeterminate state:

boolean isIndeterminate = checkBox1.isIndeterminate();

Note, that if a CheckBox is not in the indeterminate state, it is either selected or not selected, which can be seen via its isSelected() method shown earlier.