javafx combobox checkbox multiselect filtered - javafx

Question

I have looked days on any ready solution for the subject of having TOGETHER in javafx (pure) :
Combobox
Multiselect of items through Checkboxes
Filter items by the "editable" part of the Combobox
I have had no luck finding what I was looking for so I have now a working solution taken from different separate solution... Thank you to all for this !
Now I would like to know if what I have done follows the best practices or not... It's working... but is it "ugly" solution ? Or would that be a sort of base anyone could use ?
I tied to comment as much as I could, and also kept the basic comment of the sources :
user:2436221 (Jonatan Stenbacka) --> https://stackoverflow.com/a/34609439/14021197
user:5844477 (Sai Dandem) --> https://stackoverflow.com/a/52471561/14021197
Thank you for your opinions, and suggestions...
Here is the working example :
package application;
import com.sun.javafx.scene.control.skin.ComboBoxListViewSkin;
import javafx.application.Application;
import javafx.application.Platform;
import javafx.beans.property.BooleanProperty;
import javafx.beans.property.SimpleBooleanProperty;
import javafx.beans.property.SimpleStringProperty;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.collections.transformation.FilteredList;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.CheckBox;
import javafx.scene.control.ComboBox;
import javafx.scene.control.ListCell;
import javafx.scene.control.ListView;
import javafx.scene.layout.HBox;
import javafx.scene.text.Text;
import javafx.stage.Stage;
import javafx.util.Callback;
#SuppressWarnings ("restriction") // Only applies for PROTECTD library : com.sun.javafx.scene.control.skin.ComboBoxListViewSkin
public class MultiSelectFiltered2 extends Application {
// These 2 next fields are used in order to keep the FILTERED TEXT entered by user.
private String aFilterText = "";
private boolean isUserChangeText = true;
public void start(Stage stage) {
Text txt = new Text(); // A place where to expose the result of checked items.
HBox vbxRoot = new HBox(); // A basic root to order the GUI
ComboBox<ChbxItems> cb = new ComboBox<ChbxItems>() {
// This part is needed in order to NOT have the list hided when an item is selected...
// TODO --> Seems a little ugly to me since this part is the PROTECTED part !
protected javafx.scene.control.Skin<?> createDefaultSkin() {
return new ComboBoxListViewSkin<ChbxItems>(this) {
#Override
protected boolean isHideOnClickEnabled() {
return false;
}
};
}
};
cb.setEditable(true);
// Create a list with some dummy values.
ObservableList<ChbxItems> items = FXCollections.observableArrayList();
items.add(new ChbxItems("One"));
items.add(new ChbxItems("Two"));
items.add(new ChbxItems("Three"));
items.add(new ChbxItems("Four"));
items.add(new ChbxItems("Five"));
items.add(new ChbxItems("Six"));
items.add(new ChbxItems("Seven"));
items.add(new ChbxItems("Eight"));
items.add(new ChbxItems("Nine"));
items.add(new ChbxItems("Ten"));
// Create a FilteredList wrapping the ObservableList.
FilteredList<ChbxItems> filteredItems = new FilteredList<ChbxItems>(items, p -> true);
// Add a listener to the textProperty of the combo box editor. The
// listener will simply filter the list every time the input is changed
// as long as the user hasn't selected an item in the list.
cb.getEditor().textProperty().addListener((obs, oldValue, newValue) -> {
// This needs to run on the GUI thread to avoid the error described here:
// https://bugs.openjdk.java.net/browse/JDK-8081700.
Platform.runLater(() -> {
if (isUserChangeText) {
aFilterText = cb.getEditor().getText();
}
// If the no item in the list is selected or the selected item
// isn't equal to the current input, we re-filter the list.
filteredItems.setPredicate(item -> {
boolean isPartOfFilter = true;
// We return true for any items that starts with the
// same letters as the input. We use toUpperCase to
// avoid case sensitivity.
if (!item.getText().toUpperCase().startsWith(newValue.toUpperCase())) {
isPartOfFilter = false;
}
return isPartOfFilter;
});
isUserChangeText = true;
});
});
cb.setCellFactory(new Callback<ListView<ChbxItems>, ListCell<ChbxItems>>() {
#Override
public ListCell<ChbxItems> call(ListView<ChbxItems> param) {
return new ListCell<ChbxItems>() {
private CheckBox chbx = new CheckBox();
// This 'just open bracket' opens the newly CheckBox Class specifics
{
chbx.setOnAction(new EventHandler<ActionEvent>() {
// This VERY IMPORTANT part will effectively set the ChbxItems item
// The argument is never used, thus left as 'arg0'
#Override
public void handle(ActionEvent arg0) {
// This is where the usual update of the check box refreshes the editor' text of the parent combo box... we want to avoid this ;-)
isUserChangeText = false;
// The one line without which your check boxes are going to be checked depending on the position in the list... which changes when the list gets filtered.
getListView().getSelectionModel().select(getItem());
// Updating the exposed text from the list of checked items... This is added here to have a 'live' update.
txt.setText(updateListOfValuesChosen(items));
}
});
}
private BooleanProperty booleanProperty; //Will be used for binding... explained bellow.
#Override
protected void updateItem(ChbxItems item, boolean empty) {
super.updateItem(item, empty);
if (!empty) {
// Binding is used in order to link the checking (selecting) of the item, with the actual 'isSelected' field of the ChbxItems object.
if (booleanProperty != null) {
chbx.selectedProperty().unbindBidirectional(booleanProperty);
}
booleanProperty = item.isSelectedProperty();
chbx.selectedProperty().bindBidirectional(booleanProperty);
// This is the usual part for the look of the cell
setGraphic(chbx);
setText(item.getText() + "");
} else {
// Look of the cell, which has to be "reseted" if no item is attached (empty is true).
setGraphic(null);
setText("");
}
// Setting the 'editable' part of the combo box to what the USER wanted
// --> When 'onAction' of the check box, the 'behind the scene' update will refresh the combo box editor with the selected object reference otherwise.
cb.getEditor().setText(aFilterText);
cb.getEditor().positionCaret(aFilterText.length());
}
};
}
});
// Yes, it's the filtered items we want to show in the combo box...
// ...but we want to run through the original items to find out if they are checked or not.
cb.setItems(filteredItems);
// Some basic cosmetics
vbxRoot.setSpacing(15);
vbxRoot.setPadding(new Insets(25));
vbxRoot.setAlignment(Pos.TOP_LEFT);
// Adding the visual children to root VBOX
vbxRoot.getChildren().addAll(txt, cb);
// Ordinary Scene & Stage settings and initialization
Scene scene = new Scene(vbxRoot);
stage.setScene(scene);
stage.show();
}
// Just a method to expose the list of items checked...
// This is the result that will be probably the input for following code.
// -->
// If the class ChbxItems had a custom object rather than 'text' field,
// the resulting checked items from here could be a list of these custom objects --> VERY USEFUL
private String updateListOfValuesChosen(ObservableList<ChbxItems> items) {
StringBuilder sb = new StringBuilder();
items.stream().filter(ChbxItems::getIsSelected).forEach(cbitem -> {
sb.append(cbitem.getText()).append("\n");
});
return sb.toString();
}
// The CHECKBOX object, with 2 fields :
// - The boolean part (checked ot not)
// - The text part which is shown --> Could be a custom object with 'toString()' overridden ;-)
class ChbxItems {
private SimpleStringProperty text = new SimpleStringProperty();
private BooleanProperty isSelected = new SimpleBooleanProperty();
public ChbxItems(String sText) {
setText(sText);
}
public void setText(String text) {
this.text.set(text);
}
public String getText() {
return text.get();
}
public SimpleStringProperty textProperty() {
return text;
}
public void setIsSelected(boolean isSelected) {
this.isSelected.set(isSelected);
}
public boolean getIsSelected() {
return isSelected.get();
}
public BooleanProperty isSelectedProperty() {
return isSelected;
}
}
public static void main(String[] args) {
launch();
}
}