Get Checkbox value in a table in JavaFX

Question

I have a table and it has a column with checkboxes.

On a button click I want to find out which checkboxes are checked and which are not. So far I managed to create checkboxes in a table. The code is as follows.

public class TTEs implements Initializable {

    @FXML
    private TableView<TestObject> tableReport;

    @FXML
    private TableColumn<TestObject, String> name;

    @FXML
    private TableColumn<TestObject, Boolean> checkbox;

    @FXML
    public void getValues() {        
        //the method will get what check boxes are checked (this part is the problem)
    }

    @Override
    public void initialize(URL arg0, ResourceBundle arg1) { 
        ObservableList<TestObject> data = FXCollections.observableArrayList();
        data.add(new TestObject("Test 1", true));
        data.add(new TestObject("Test 2", false));

        tableReport.setItems(data);

        name.setCellValueFactory(new PropertyValueFactory<TestObject, String>("name"));
        checkbox.setCellValueFactory(new PropertyValueFactory<TestObject, Boolean>("checked"));

        checkbox.setCellFactory(new Callback<TableColumn<TestObject, Boolean>,
            TableCell<TestObject, Boolean>>() {

            public TableCell<TestObject, Boolean> call(TableColumn<TestObject, Boolean> p) {
                return new CheckBoxTableCell<TestObject, Boolean>();
            }
        });
    }

    //CheckBoxTableCell for creating a CheckBox in a table cell
    public static class CheckBoxTableCell<S, T> extends TableCell<S, T> {
        private final CheckBox checkBox;
        private ObservableValue<T> ov;

        public CheckBoxTableCell() {
            this.checkBox = new CheckBox();
            this.checkBox.setAlignment(Pos.CENTER);

            setAlignment(Pos.CENTER);
            setGraphic(checkBox);
        } 

        @Override public void updateItem(T item, boolean empty) {
            super.updateItem(item, empty);
            if (empty) {
                setText(null);
                setGraphic(null);
            } else {
                setGraphic(checkBox);
                if (ov instanceof BooleanProperty) {
                    checkBox.selectedProperty().unbindBidirectional((BooleanProperty) ov);
                }
                ov = getTableColumn().getCellObservableValue(getIndex());
                if (ov instanceof BooleanProperty) {
                    checkBox.selectedProperty().bindBidirectional((BooleanProperty) ov);
                }
            }
        }
    }
}

When I debug, I find that:

        ov = getTableColumn().getCellObservableValue(getIndex());
        if (ov instanceof BooleanProperty) {
            checkBox.selectedProperty().bindBidirectional((BooleanProperty) ov);
        }

In the above condition, it never goes inside the if statement, meaning that the ov is not an instance of BooleanProperty. But when I print the class of ov,

System.out.println(ov.getClass().getName());

it prints as

javafx.beans.property.ReadOnlyObjectWrapper

ReadOnlyObjectWrapper is a subclass of BooleanProperty, so why is the instanceof check not working?

Answer 1

The main problem with your approach is the CheckBoxTableCell usage: A Cell is a heavily reused 'rendering' machine. If you try to add a state, like the CheckBox variable, you are in trouble.

The most simple fix to your problem is to allocate the checkbox each time. The following code provides a working checkbox column:

public static class Member {
    private StringProperty myName;
    private BooleanProperty myCheck;

    public Member(String name, boolean checked) {
        myName = new SimpleStringProperty(name);
        myCheck = new SimpleBooleanProperty(checked);
    }

    public StringProperty nameProperty() { return myName; }    
    public BooleanProperty checkProperty() { return myCheck; }
}

VBox testTable6(VBox box) { // check box bind to cell property
    ObservableList<Member> members = FXCollections.observableArrayList();

    members.add(new Member("peter", true));
    members.add(new Member("gernot", true));
    members.add(new Member("fritz", false));

    TableView<Member> table = new TableView<Member>();
    table.prefHeightProperty().bind(box.heightProperty());
    table.setItems(members);

    TableColumn<Member,String> c1 = new TableColumn<Member,String>("Name");
    c1.setCellValueFactory(new PropertyValueFactory<Member,String>("name"));
    table.getColumns().add(c1);

    TableColumn<Member,Boolean> c2 = new TableColumn<Member,Boolean>("Membercheck");
    c2.setCellValueFactory(new PropertyValueFactory<Member,Boolean>("check"));
    c2.setCellFactory(column -> new TableCell<Member, Boolean>(){
        public void updateItem(Boolean check, boolean empty) {
            super.updateItem(check, empty);
            if (check == null || empty) {
                setGraphic(null);
            } else {
                CheckBox box = new CheckBox();
                BooleanProperty checked = (BooleanProperty)column.getCellObservableValue(getIndex());
                box.setSelected(checked.get());
                box.selectedProperty().bindBidirectional(checked);
                setGraphic(box);
            }
        }
    }
            );
    table.getColumns().add(c2);

    box.getChildren().addAll(table);
    return box;
}

As the bidirectional property binding is a weak binding, carbage collection will work properly even if you are unable to unbind explicitely.

The unchecked cast to BooleanProperty is not a good style anyhow here, sorry. Consider to access the whole object using:

...
Member member = table.getItems().get(getIndex());
box.setSelected(member.checkProperty().get());
box.selectedProperty().bindBidirectional(member.checkProperty());
....

by the way: the birdeirectional binding will NOT set the selected property in that moment, only if it is changed afterward! so the explicit assignment:

box.setSelected(member.checkProperty().get());

is mandatory here.

Answer 2

package checkboxtablecelltest;

import javafx.application.Application;
import javafx.beans.property.BooleanProperty;
import javafx.beans.property.SimpleBooleanProperty;
import javafx.beans.property.SimpleStringProperty;
import javafx.beans.property.StringProperty;
import javafx.beans.value.ChangeListener;
import javafx.beans.value.ObservableValue;
import javafx.collections.FXCollections;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.SelectionMode;
import javafx.scene.control.TableColumn;
import javafx.scene.control.TableView;
import javafx.scene.control.cell.CheckBoxTableCell;
import javafx.scene.control.cell.PropertyValueFactory;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.HBox;
import javafx.stage.Stage;

/**
 *
 * @author reegan
 */
public class CheckBoxTableCellTest extends Application {

    @Override   
    public void start(Stage primaryStage) {
        final TableView<Person> tableView = new TableView<Person>();
        tableView.getSelectionModel().setSelectionMode(SelectionMode.MULTIPLE);
        tableView.setItems(FXCollections.observableArrayList(
                new Person("Robert", "Plant"),
                new Person("Neil", "Young"),
                new Person("Willie", "Nelson"),
                new Person("Natalie", "Merchant")));
        tableView.getItems().get(3).setVegetarian(true);
        final TableColumn<Person, String> firstNameCol = new TableColumn<Person, String>("First Name");
        final TableColumn<Person, String> lastNameCol = new TableColumn<Person, String>("Last Name");
        final TableColumn<Person, Boolean> vegetarianCol = new TableColumn<Person, Boolean>("Vegetarian");
        tableView.getColumns().addAll(firstNameCol, lastNameCol, vegetarianCol);
        firstNameCol.setCellValueFactory(new PropertyValueFactory<Person, String>("firstName"));
        lastNameCol.setCellValueFactory(new PropertyValueFactory<Person, String>("lastName"));
        vegetarianCol.setCellValueFactory(new PropertyValueFactory<Person, Boolean>("vegetarian"));
        vegetarianCol.setCellFactory(CheckBoxTableCell.forTableColumn(vegetarianCol));
        vegetarianCol.setEditable(true);
        tableView.setEditable(true);

        final BorderPane root = new BorderPane();
        root.setCenter(tableView);

        final HBox controls = new HBox(5);
        final Button infoButton = new Button("Show details");
        infoButton.setOnAction(new EventHandler<ActionEvent>() {
            @Override
            public void handle(ActionEvent event) {
                for (Person p : tableView.getItems()) {
                    System.out.printf("%s %s (%svegetarian)%n", p.getFirstName(),
                            p.getLastName(), p.isVegetarian() ? "" : "not ");
                            System.out.println(tableView.getSelectionModel().getSelectedItems());

                }
                System.out.println();
            }
        });
        controls.getChildren().add(infoButton);
        root.setBottom(controls);

        Scene scene = new Scene(root, 300, 400);
        primaryStage.setScene(scene);
        primaryStage.show();
    }

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

    public static class Person {

        private StringProperty firstName;
        private StringProperty lastName;
        private BooleanProperty vegetarian;

        public Person(String firstName, String lastName) {
            this.firstName = new SimpleStringProperty(firstName);
            this.lastName = new SimpleStringProperty(lastName);
            this.vegetarian = new SimpleBooleanProperty(false);
        }

        public String getFirstName() {
            return firstName.get();
        }

        public String getLastName() {
            return lastName.get();
        }

        public boolean isVegetarian() {
            return vegetarian.get();
        }

        public void setFirstName(String firstName) {
            this.firstName.set(firstName);
        }

        public void setLastName(String lastName) {
            this.lastName.set(lastName);
        }

        public void setVegetarian(boolean vegetarian) {
            this.vegetarian.set(vegetarian);
        }

        public StringProperty firstNameProperty() {
            return firstName;
        }

        public StringProperty lastNameProperty() {
            return lastName;
        }

        public BooleanProperty vegetarianProperty() {
            return vegetarian;
        }
    }
}

`

Answer 3

Tested on Java 8.
Only 4 simple things.

1) Make CheckBoxCellFactory class. Put somewhere in your project.

public class CheckBoxCellFactory implements Callback {
    @Override
    public TableCell call(Object param) {
        CheckBoxTableCell<Person,Boolean> checkBoxCell = new CheckBoxTableCell();
        return checkBoxCell;
    }
}

2) Your model class. Person for example.

public static class Person {
   private SimpleBooleanProperty checked = new SimpleBooleanProperty(false);
   // other columns here

    public SimpleBooleanProperty checkedProperty() {
        return this.checked;
    }

    public java.lang.Boolean getChecked() {
        return this.checkedProperty().get();
    }

    public void setChecked(final java.lang.Boolean checked) {
        this.checkedProperty().set(checked);
    }

    // getter/setter for other columns

}

3) Made modifications in your fxml file. The section of your TableView -> TableColumn gonna look like this:

<TableColumn fx:id="checkBoxTableColumn" maxWidth="34.0" minWidth="26.0" prefWidth="34.0" resizable="false" sortable="false">   
<cellValueFactory><PropertyValueFactory property="checked" /></cellValueFactory>
<cellFactory><partarch.fx.CheckBoxCellFactory /></cellFactory>
</TableColumn>

4) If you want to make your checkbox being editable

• 4.1 Open fxml in the Scene Builder.
• 4.2 Select checkBox column and then check "Editable" property in the Properties pane.
• 4.3 Select TableView containing your checkbox and do the same(check "Editable" property in the Properties pane).

Implementation in binaries on SF and source on GitHub

Answer 4

A little off topic - but in Kotlin you can do this:

    isPvtColumn.cellFactory = Callback { CheckBoxTableCell<KeyWithProperties, Boolean>() }

    isPvtColumn.cellValueFactory = Callback {
        a -> a.value.private
    }

This is all there is to it

Answer 5

In the initialize method, switch your custom factory for the one provided by JavaFX:

@Override
public void initialize(URL arg0, ResourceBundle arg1) {

     ObservableList<TestObject> data = FXCollections.observableArrayList();
     data.add(new TestObject("Test 1", true));
     data.add(new TestObject("Test 2", false));

     tableReport.setItems(data);

     name.setCellValueFactory(new PropertyValueFactory<TestObject, String>("name"));
     checkbox.setCellValueFactory(new PropertyValueFactory<TestObject, Boolean>("checked"));

     checkbox.setCellFactory(
         CheckBoxTableCell.forTableColumn(checkbox)
     );

}

Now your data is binded to the column and you can iterate over the items and check for the "checked" field:

@FXML
public void getValues(){        
    ObservableList<TestObject> data = tableReport.getItems();

    for (TestObject item : data){
        //check the boolean value of each item to determine checkbox state
    }
}

Answer 6

Loop through the data model of your TableView checking the boolean value that is bound to each CheckBox.

@FXML
public void getValues(){        
    ObservableList<TestObject> data = tableReport.getItems();

    for (TestObject item : data){
        //check the boolean value of each item to determine checkbox state
    }
}