JavaFX ComboBox with CheckBoxes

I try to create a JavaFX ComboBox which holds CheckBoxes in the dropdown menu.
The ComboBox shall be editable and gets fed by a simple Class lets call it CheckItem.
the list of CheckItems shall be checkable - and shall not close the dropdown menu after a selection is made.

JavaFX

ComboBox

CheckBoxes

ComboBox

Class

CheckItem

CheckItems

finally the Text in the ComboBox should be available and a Selection (all checked Items)

ComboBox

(1) a ComboBox rendering the CheckItem as CheckedBox with correct selection

ComboBox

CheckItem

CheckedBox

(2) gaining the Text from the ComboBox

ComboBox

(1) After clicking on one item the dropdown closes & selection state of the item does not change.

(2) As far as i noticed its only possible to have one item selected at a time?

here is my code for testing the stuff:

public class ComboButtonSample extends Application {

@Override
public void start(Stage stage)
final ObservableList<CheckItem> items = fetchItems();
ComboBox<CheckItem> combo = createComboBox(items);
combo.setPromptText("enter searchstring here");
combo.setEditable(true);


// order the components vertically
VBox vBox = new VBox();
vBox.getChildren().add(combo);

// Button to write out the text and the items of the combobox
Button btn = new Button();
btn.setText("combo text to console");
btn.setOnAction((event) ->
System.out.println("Text is: "+combo.getEditor().getText());
System.out.println("Content is: ");
for (Iterator<CheckItem> iterator = combo.getItems().iterator(); iterator.hasNext();)
CheckItem ci = (CheckItem) iterator.next();
System.out.println(String.format("[%s] %s -> %s", ci.selected ? "X" : " ",ci.getDisplayName(), ci.getInternalName()));


);

vBox.getChildren().add(btn);

// show you do not need any code to change the selection of the box.
CheckBox checkBox = new CheckBox();
checkBox.setText("test box");
vBox.getChildren().add(checkBox);

stage.setScene(new Scene(vBox));
stage.show();


private ComboBox<CheckItem> createComboBox(ObservableList<CheckItem> data)
ComboBox<CheckItem> combo = new ComboBox<>();
combo.getItems().addAll(data);
combo.setCellFactory(listView -> new CheckItemListCell());
return combo;


class CheckItemListCell extends ListCell<CheckItem>
private final CheckBox btn;

CheckItemListCell()
setContentDisplay(ContentDisplay.GRAPHIC_ONLY);
btn = new CheckBox();


@Override
protected void updateItem(CheckItem item, boolean empty) empty)
setGraphic(null);
else
btn.setText(item.getDisplayName());
btn.selectedProperty().setValue(item.selected);
setGraphic(btn);




private ObservableList<CheckItem> fetchItems()
final ObservableList<CheckItem> data = FXCollections
.observableArrayList();
for (int i = 1; i < 15; i++)
CheckItem chkItem = new CheckItem();
chkItem.selected = i%3==0;
chkItem.setDisplayName("DisplayName" + i);
chkItem.setInternalName("InternalName" + i);
data.add(chkItem);

return data;


public static void main(String args)
launch(args);



public class CheckItem
boolean selected;
String displayName;
String internalName;

public boolean isChecked()
return selected;


public void setChecked(boolean checked)
this.selected = checked;


public String getDisplayName()
return displayName;


public void setDisplayName(String displayName)
this.displayName = displayName;


public String getInternalName()
return internalName;


public void setInternalName(String internalName)
this.internalName = internalName;




ComboBox

MenuButton

CheckMenuItem

2 Answers
2

If you have problems in your implementation, you should have a look to the CheckComboBox control in the ControlsFX project.

Source code can be found here.

My sample code:

CheckedComboBox

class Person

public class Person

private StringProperty name = new SimpleStringProperty();
private ObjectProperty<LocalDate> birthday = new SimpleObjectProperty<>();

public Person()


public Person(String name, LocalDate birthday)
setNameValue(name);
setBirthdayValue(birthday);


public StringProperty getNameProperty()
return name;


public String getNameValue()
return name.getValue();


public void setNameValue(String value)
name.setValue(value);


public ObjectProperty<LocalDate> getBirthdayProperty()
return birthday;


public LocalDate getBirthdayValue()
return birthday.getValue();


public void setBirthdayValue(LocalDate value)
birthday.setValue(value);


@Override
public String toString()
return getNameValue()+" ("+getBirthdayValue()+")";





simple wrapper

public class ComboBoxItemWrap<T>

private BooleanProperty check = new SimpleBooleanProperty(false);
private ObjectProperty<T> item = new SimpleObjectProperty<>();

ComboBoxItemWrap()


ComboBoxItemWrap(T item)
this.item.set(item);


ComboBoxItemWrap(T item, Boolean check)
this.item.set(item);
this.check.set(check);


public BooleanProperty checkProperty()
return check;


public Boolean getCheck()
return check.getValue();


public void setCheck(Boolean value)
check.set(value);


public ObjectProperty<T> itemProperty()
return item;


public T getItem()
return item.getValue();


public void setItem(T value)
item.setValue(value);


@Override
public String toString()
return item.getValue().toString();




sample code

public class MainApplication extends Application

@Override
public void start(Stage stage)
Scene scene = new Scene(new VBox(), 450, 250);

ComboBox<ComboBoxItemWrap<Person>> cb = new ComboBox<>();

@SuppressWarnings("unchecked")
ObservableList<ComboBoxItemWrap<Person>> options = FXCollections.observableArrayList(
new ComboBoxItemWrap<>(new Person("A", LocalDate.now().minusDays(12))),
new ComboBoxItemWrap<>(new Person("B", LocalDate.now().minusDays(34))),
new ComboBoxItemWrap<>(new Person("C", LocalDate.now().minusDays(48))),
new ComboBoxItemWrap<>(new Person("D", LocalDate.now().minusDays(56))),
new ComboBoxItemWrap<>(new Person("E", LocalDate.now().minusDays(72))),
new ComboBoxItemWrap<>(new Person("F", LocalDate.now().minusDays(96)))
);

cb.setCellFactory( c ->
ListCell<ComboBoxItemWrap<Person>> cell = new ListCell<>()
@Override
protected void updateItem(ComboBoxItemWrap<Person> item, boolean empty)
super.updateItem(item, empty);
if (!empty)
final CheckBox cb = new CheckBox(item.toString());
cb.selectedProperty().bind(item.checkProperty());
setGraphic(cb);


;

cell.addEventFilter(MouseEvent.MOUSE_RELEASED, event ->
cell.getItem().checkProperty().set(!cell.getItem().checkProperty().get());
StringBuilder sb = new StringBuilder();
cb.getItems().filtered( f-> f!=null).filtered( f-> f.getCheck()).forEach( p ->
sb.append("; "+p.getItem());
);
final String string = sb.toString();
cb.setPromptText(string.substring(Integer.min(2, string.length())));
);

return cell;
);

cb.setItems(options);


VBox root = (VBox) scene.getRoot();

Button bt = new Button("test");

bt.setOnAction(event ->
cb.getItems().filtered( f -> f.getCheck()).forEach( item -> System.out.println(item.getItem()));
);

root.getChildren().addAll(cb, bt);
stage.setScene(scene);
stage.show();


public static void main(String args)
launch(args);




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