AutoComplete ComboBox in JavaFX

Question

I'm looking for a way to add autocomplete to a JavaFX ComboBox. After searching a lot it's time to ask here.

This AutoFillBox is known but not what I'm searching. What I want is a editable combobox and while typing the list should filtered. But I want also to open the list without typing and seeing the whole items.

Any idea?

Answer 1

I look around and try something. This look good:

public void handle( KeyEvent event ) {
        if( event.getCode() == KeyCode.BACK_SPACE)
            s = s.substring( 0, s.length() - 1 );
        else s += event.getText();
        for( String item: items ) {
            if( item.startsWith( s ) ) sm.select( item );
        }
    }

A Keyhandle for select the item with matching start charakter.

I hope this help you

Answer 2

Don't know if this is still relevant, but came to this topic. Tried the upper approaches, made one variation my self. But by far, this fxapps blog one turned out to be best looking(but had to make some modifications since my item list wasn't static, but still...). Hope this will held the next person who will find this topic interesting.

Answer 3

here is a simple one

public class AutoShowComboBoxHelper {
    public AutoShowComboBoxHelper(final ComboBox<String> comboBox, final Callback<String, String> textBuilder) {
        final ObservableList<String> items = FXCollections.observableArrayList(comboBox.getItems());

        comboBox.getEditor().textProperty().addListener((ov, o, n) -> {
            if (n.equals(comboBox.getSelectionModel().getSelectedItem())) {
                return;
            }

            comboBox.hide();
            final FilteredList<String> filtered = items.filtered(s -> textBuilder.call(s).toLowerCase().contains(n.toLowerCase()));
            if (filtered.isEmpty()) {
                comboBox.getItems().setAll(items);
            } else {
                comboBox.getItems().setAll(filtered);
                comboBox.show();
            }
        });
    }
}

and a way to use it:

new AutoShowComboBoxHelper(combo, item -> buildTextToCompare(item));

For the sake of simplicity I used String::contains in this code, for better performance use org.apache.commons.lang3.StringUtils::containsIgnoreCase

Answer 4

I found a solution that's working for me:

public class AutoCompleteComboBoxListener<T> implements EventHandler<KeyEvent> {

    private ComboBox comboBox;
    private StringBuilder sb;
    private ObservableList<T> data;
    private boolean moveCaretToPos = false;
    private int caretPos;

    public AutoCompleteComboBoxListener(final ComboBox comboBox) {
        this.comboBox = comboBox;
        sb = new StringBuilder();
        data = comboBox.getItems();

        this.comboBox.setEditable(true);
        this.comboBox.setOnKeyPressed(new EventHandler<KeyEvent>() {

            @Override
            public void handle(KeyEvent t) {
                comboBox.hide();
            }
        });
        this.comboBox.setOnKeyReleased(AutoCompleteComboBoxListener.this);
    }

    @Override
    public void handle(KeyEvent event) {

        if(event.getCode() == KeyCode.UP) {
            caretPos = -1;
            moveCaret(comboBox.getEditor().getText().length());
            return;
        } else if(event.getCode() == KeyCode.DOWN) {
            if(!comboBox.isShowing()) {
                comboBox.show();
            }
            caretPos = -1;
            moveCaret(comboBox.getEditor().getText().length());
            return;
        } else if(event.getCode() == KeyCode.BACK_SPACE) {
            moveCaretToPos = true;
            caretPos = comboBox.getEditor().getCaretPosition();
        } else if(event.getCode() == KeyCode.DELETE) {
            moveCaretToPos = true;
            caretPos = comboBox.getEditor().getCaretPosition();
        }

        if (event.getCode() == KeyCode.RIGHT || event.getCode() == KeyCode.LEFT
                || event.isControlDown() || event.getCode() == KeyCode.HOME
                || event.getCode() == KeyCode.END || event.getCode() == KeyCode.TAB) {
            return;
        }

        ObservableList list = FXCollections.observableArrayList();
        for (int i=0; i<data.size(); i++) {
            if(data.get(i).toString().toLowerCase().startsWith(
                AutoCompleteComboBoxListener.this.comboBox
                .getEditor().getText().toLowerCase())) {
                list.add(data.get(i));
            }
        }
        String t = comboBox.getEditor().getText();

        comboBox.setItems(list);
        comboBox.getEditor().setText(t);
        if(!moveCaretToPos) {
            caretPos = -1;
        }
        moveCaret(t.length());
        if(!list.isEmpty()) {
            comboBox.show();
        }
    }

    private void moveCaret(int textLength) {
        if(caretPos == -1) {
            comboBox.getEditor().positionCaret(textLength);
        } else {
            comboBox.getEditor().positionCaret(caretPos);
        }
        moveCaretToPos = false;
    }

}

You can call it with

new AutoCompleteComboBoxListener<>(comboBox);

---

It's based on this and I customized it to fit my needs.

Feel free to use it and if anybody can improve it, tell me.

Answer 5

Based on Jonatan's answer, I was able to build the following solution:

import com.sun.javafx.scene.control.skin.ComboBoxListViewSkin;
import javafx.application.Application;
import javafx.application.Platform;
import javafx.beans.Observable;
import javafx.beans.property.*;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.collections.transformation.FilteredList;
import javafx.scene.Scene;
import javafx.scene.control.ComboBox;
import javafx.scene.control.Control;
import javafx.scene.control.ListView;
import javafx.scene.input.KeyEvent;
import javafx.scene.layout.HBox;
import javafx.stage.Stage;

import java.util.ArrayList;
import java.util.List;

public class Main extends Application
{
    public static class HideableItem<T>
    {
        private final ObjectProperty<T> object = new SimpleObjectProperty<>();
        private final BooleanProperty hidden = new SimpleBooleanProperty();

        private HideableItem(T object)
        {
            setObject(object);
        }

        private ObjectProperty<T> objectProperty(){return this.object;}
        private T getObject(){return this.objectProperty().get();}
        private void setObject(T object){this.objectProperty().set(object);}

        private BooleanProperty hiddenProperty(){return this.hidden;}
        private boolean isHidden(){return this.hiddenProperty().get();}
        private void setHidden(boolean hidden){this.hiddenProperty().set(hidden);}

        @Override
        public String toString()
        {
            return getObject() == null ? null : getObject().toString();
        }
    }

    public void start(Stage stage)
    {
        List<String> countries = new ArrayList<>();

        countries.add("Afghanistan");
        countries.add("Albania");
        countries.add("Algeria");
        countries.add("Andorra");
        countries.add("Angola");
        countries.add("Antigua and Barbuda");
        countries.add("Argentina");
        countries.add("Armenia");
        countries.add("Australia");
        countries.add("Austria");
        countries.add("Azerbaijan");
        countries.add("Bahamas");
        countries.add("Bahrain");
        countries.add("Bangladesh");
        countries.add("Barbados");
        countries.add("Belarus");
        countries.add("Belgium");
        countries.add("Belize");
        countries.add("Benin");
        countries.add("Bhutan");
        countries.add("Bolivia");
        countries.add("Bosnia and Herzegovina");
        countries.add("Botswana");
        countries.add("Brazil");
        countries.add("Brunei");
        countries.add("Bulgaria");
        countries.add("Burkina Faso");
        countries.add("Burundi");
        countries.add("Cabo Verde");
        countries.add("Cambodia");
        countries.add("Cameroon");
        countries.add("Canada");
        countries.add("Central African Republic (CAR)");
        countries.add("Chad");
        countries.add("Chile");
        countries.add("China");
        countries.add("Colombia");
        countries.add("Comoros");
        countries.add("Democratic Republic of the Congo");
        countries.add("Republic of the Congo");
        countries.add("Costa Rica");
        countries.add("Cote d'Ivoire");
        countries.add("Croatia");
        countries.add("Cuba");
        countries.add("Cyprus");
        countries.add("Czech Republic");
        countries.add("Denmark");
        countries.add("Djibouti");
        countries.add("Dominica");
        countries.add("Dominican Republic");
        countries.add("Ecuador");
        countries.add("Egypt");
        countries.add("El Salvador");
        countries.add("Equatorial Guinea");
        countries.add("Eritrea");
        countries.add("Estonia");
        countries.add("Ethiopia");
        countries.add("Fiji");
        countries.add("Finland");
        countries.add("France");
        countries.add("Gabon");
        countries.add("Gambia");
        countries.add("Georgia");
        countries.add("Germany");
        countries.add("Ghana");
        countries.add("Greece");
        countries.add("Grenada");
        countries.add("Guatemala");
        countries.add("Guinea");
        countries.add("Guinea-Bissau");
        countries.add("Guyana");
        countries.add("Haiti");
        countries.add("Honduras");
        countries.add("Hungary");
        countries.add("Iceland");
        countries.add("India");
        countries.add("Indonesia");
        countries.add("Iran");
        countries.add("Iraq");
        countries.add("Ireland");
        countries.add("Israel");
        countries.add("Italy");
        countries.add("Jamaica");
        countries.add("Japan");
        countries.add("Jordan");
        countries.add("Kazakhstan");
        countries.add("Kenya");
        countries.add("Kiribati");
        countries.add("Kosovo");
        countries.add("Kuwait");
        countries.add("Kyrgyzstan");
        countries.add("Laos");
        countries.add("Latvia");
        countries.add("Lebanon");
        countries.add("Lesotho");
        countries.add("Liberia");
        countries.add("Libya");
        countries.add("Liechtenstein");
        countries.add("Lithuania");
        countries.add("Luxembourg");
        countries.add("Macedonia (FYROM)");
        countries.add("Madagascar");
        countries.add("Malawi");
        countries.add("Malaysia");
        countries.add("Maldives");
        countries.add("Mali");
        countries.add("Malta");
        countries.add("Marshall Islands");
        countries.add("Mauritania");
        countries.add("Mauritius");
        countries.add("Mexico");
        countries.add("Micronesia");
        countries.add("Moldova");
        countries.add("Monaco");
        countries.add("Mongolia");
        countries.add("Montenegro");
        countries.add("Morocco");
        countries.add("Mozambique");
        countries.add("Myanmar (Burma)");
        countries.add("Namibia");
        countries.add("Nauru");
        countries.add("Nepal");
        countries.add("Netherlands");
        countries.add("New Zealand");
        countries.add("Nicaragua");
        countries.add("Niger");
        countries.add("Nigeria");
        countries.add("North Korea");
        countries.add("Norway");
        countries.add("Oman");
        countries.add("Pakistan");
        countries.add("Palau");
        countries.add("Palestine");
        countries.add("Panama");
        countries.add("Papua New Guinea");
        countries.add("Paraguay");
        countries.add("Peru");
        countries.add("Philippines");
        countries.add("Poland");
        countries.add("Portugal");
        countries.add("Qatar");
        countries.add("Romania");
        countries.add("Russia");
        countries.add("Rwanda");
        countries.add("Saint Kitts and Nevis");
        countries.add("Saint Lucia");
        countries.add("Saint Vincent and the Grenadines");
        countries.add("Samoa");
        countries.add("San Marino");
        countries.add("Sao Tome and Principe");
        countries.add("Saudi Arabia");
        countries.add("Senegal");
        countries.add("Serbia");
        countries.add("Seychelles");
        countries.add("Sierra Leone");
        countries.add("Singapore");
        countries.add("Slovakia");
        countries.add("Slovenia");
        countries.add("Solomon Islands");
        countries.add("Somalia");
        countries.add("South Africa");
        countries.add("South Korea");
        countries.add("South Sudan");
        countries.add("Spain");
        countries.add("Sri Lanka");
        countries.add("Sudan");
        countries.add("Suriname");
        countries.add("Swaziland");
        countries.add("Sweden");
        countries.add("Switzerland");
        countries.add("Syria");
        countries.add("Taiwan");
        countries.add("Tajikistan");
        countries.add("Tanzania");
        countries.add("Thailand");
        countries.add("Timor-Leste");
        countries.add("Togo");
        countries.add("Tonga");
        countries.add("Trinidad and Tobago");
        countries.add("Tunisia");
        countries.add("Turkey");
        countries.add("Turkmenistan");
        countries.add("Tuvalu");
        countries.add("Uganda");
        countries.add("Ukraine");
        countries.add("United Arab Emirates (UAE)");
        countries.add("United Kingdom (UK)");
        countries.add("United States of America (USA)");
        countries.add("Uruguay");
        countries.add("Uzbekistan");
        countries.add("Vanuatu");
        countries.add("Vatican City (Holy See)");
        countries.add("Venezuela");
        countries.add("Vietnam");
        countries.add("Yemen");
        countries.add("Zambia");
        countries.add("Zimbabwe");

        ComboBox<HideableItem<String>> comboBox = createComboBoxWithAutoCompletionSupport(countries);
        comboBox.setMaxWidth(Double.MAX_VALUE);

        HBox root = new HBox();
        root.getChildren().add(comboBox);

        Scene scene = new Scene(root);
        stage.setScene(scene);
        stage.show();

        comboBox.setMinWidth(comboBox.getWidth());
        comboBox.setPrefWidth(comboBox.getWidth());
    }

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

    private static <T> ComboBox<HideableItem<T>> createComboBoxWithAutoCompletionSupport(List<T> items)
    {
        ObservableList<HideableItem<T>> hideableHideableItems = FXCollections.observableArrayList(hideableItem -> new Observable[]{hideableItem.hiddenProperty()});

        items.forEach(item ->
        {
            HideableItem<T> hideableItem = new HideableItem<>(item);
            hideableHideableItems.add(hideableItem);
        });

        FilteredList<HideableItem<T>> filteredHideableItems = new FilteredList<>(hideableHideableItems, t -> !t.isHidden());

        ComboBox<HideableItem<T>> comboBox = new ComboBox<>();
        comboBox.setItems(filteredHideableItems);

        @SuppressWarnings("unchecked")
        HideableItem<T>[] selectedItem = (HideableItem<T>[]) new HideableItem[1];

        comboBox.addEventHandler(KeyEvent.KEY_PRESSED, event ->
        {
            if(!comboBox.isShowing()) return;

            comboBox.setEditable(true);
            comboBox.getEditor().clear();
        });

        comboBox.showingProperty().addListener((observable, oldValue, newValue) ->
        {
            if(newValue)
            {
                @SuppressWarnings("unchecked")
                ListView<HideableItem> lv = ((ComboBoxListViewSkin<HideableItem>) comboBox.getSkin()).getListView();

                Platform.runLater(() ->
                {
                    if(selectedItem[0] == null) // first use
                    {
                        double cellHeight = ((Control) lv.lookup(".list-cell")).getHeight();
                        lv.setFixedCellSize(cellHeight);
                    }
                });

                lv.scrollTo(comboBox.getValue());
            }
            else
            {
                HideableItem<T> value = comboBox.getValue();
                if(value != null) selectedItem[0] = value;

                comboBox.setEditable(false);

                Platform.runLater(() ->
                {
                    comboBox.getSelectionModel().select(selectedItem[0]);
                    comboBox.setValue(selectedItem[0]);
                });
            }
        });

        comboBox.setOnHidden(event -> hideableHideableItems.forEach(item -> item.setHidden(false)));

        comboBox.getEditor().textProperty().addListener((obs, oldValue, newValue) ->
        {
            if(!comboBox.isShowing()) return;

            Platform.runLater(() ->
            {
                if(comboBox.getSelectionModel().getSelectedItem() == null)
                {
                    hideableHideableItems.forEach(item -> item.setHidden(!item.getObject().toString().toLowerCase().contains(newValue.toLowerCase())));
                }
                else
                {
                    boolean validText = false;

                    for(HideableItem hideableItem : hideableHideableItems)
                    {
                        if(hideableItem.getObject().toString().equals(newValue))
                        {
                            validText = true;
                            break;
                        }
                    }

                    if(!validText) comboBox.getSelectionModel().select(null);
                }
            });
        });

        return comboBox;
    }
}

---

UPDATE:

In Java 9+, you can access the ListView like this:

ListView<ComboBoxItem> lv = (ListView<ComboBoxItem>) ((ComboBoxListViewSkin<?>) comboBox.getSkin()).getPopupContent();

Answer 6

A bit late for the party, but I came across this thread when I had exactly this problem and really liked the answers and the approach, so thanks to everyone who contributed.

But, I don't know what you guys are putting in your ComboBox, whenever I left the box without making a specific selection a ClassCastException was thrown. So I am guessing you all mainly use the ComboBox for picking Strings, so I had to come up with a StringConverter since I am using the ComboBox for Objects (FilterCriteria).

So here is the converter, hopefully helpful to someone.

private final StringConverter<FilterCriteria> filterCriteriaStringConverter = new StringConverter<FilterCriteria>()
{
    @Override public String toString(FilterCriteria filterCriteria)
    {
        if (filterCriteria == null)
        {
            return "";
        } else
        {
            return filterCriteria.getName();
        }
    }

    @Override public FilterCriteria fromString(String string)
    {
        Optional<FilterCriteria> optionalFilterCriteria = availableTypesComboBox.getItems().stream()
          .filter(filterCriteria -> filterCriteria.getName().contains(string))
          .findFirst();
        return optionalFilterCriteria.orElseGet(() -> availableTypesComboBox.getItems().get(0));
    }
};