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package javafx.scene.control.cell;

import javafx.beans.property.BooleanProperty;
import javafx.beans.property.ObjectProperty;
import javafx.beans.property.SimpleObjectProperty;
import javafx.beans.value.ObservableValue;
import javafx.geometry.Pos;
import javafx.scene.control.CheckBox;
import javafx.scene.control.ContentDisplay;
import javafx.scene.control.ListCell;
import javafx.scene.control.ListView;
import javafx.util.Callback;
import javafx.util.StringConverter;


A class containing a ListCell implementation that draws a CheckBox node inside the cell, optionally with a label to indicate what the checkbox represents. 
The CheckBoxListCell is rendered with a CheckBox on the left-hand side of the ListView, and the text related to the list item taking up all remaining horizontal space. 
To construct an instance of this class, it is necessary to provide a Callback that, given an object of type T, will return a ObservableValue<Boolean> that represents whether the given item is selected or not. This ObservableValue will be bound bidirectionally (meaning that the CheckBox in the cell will set/unset this property based on user interactions, and the CheckBox will reflect the state of the ObservableValue<Boolean>, if it changes externally). 
Note that the CheckBoxListCell renders the CheckBox 'live', meaning that the CheckBox is always interactive and can be directly toggled by the user. This means that it is not necessary that the cell enter its editing state (usually by the user double-clicking on the cell). A side-effect of this is that the usual editing callbacks (such as on edit commit) will not be called. If you want to be notified of changes,
it is recommended to directly observe the boolean properties that are
manipulated by the CheckBox.


Type parameters:
  • <T> – The type of the elements contained within the ListView.
See Also:
Since:JavaFX 2.2
/**
 * A class containing a {@link ListCell} implementation that draws a
 * {@link CheckBox} node inside the cell, optionally with a label to indicate
 * what the checkbox represents.
 *
 * <p>The CheckBoxListCell is rendered with a CheckBox on the left-hand side of
 * the {@link ListView}, and the text related to the list item taking up all
 * remaining horizontal space.
 *
 * <p>To construct an instance of this class, it is necessary to provide a
 * {@link Callback} that, given an object of type T, will return a
 * {@code ObservableValue<Boolean>} that represents whether the given item is
 * selected or not. This ObservableValue will be bound bidirectionally (meaning
 * that the CheckBox in the cell will set/unset this property based on user
 * interactions, and the CheckBox will reflect the state of the
 * {@code ObservableValue<Boolean>}, if it changes externally).
 *
 * <p>Note that the CheckBoxListCell renders the CheckBox 'live', meaning that
 * the CheckBox is always interactive and can be directly toggled by the user.
 * This means that it is not necessary that the cell enter its
 * {@link #editingProperty() editing state} (usually by the user double-clicking
 * on the cell). A side-effect of this is that the usual editing callbacks
 * (such as {@link javafx.scene.control.ListView#onEditCommitProperty() on edit commit})
 * will <strong>not</strong> be called. If you want to be notified of changes,
 * it is recommended to directly observe the boolean properties that are
 * manipulated by the CheckBox.</p>
 *
 * @see CheckBox
 * @see ListCell
 * @param <T> The type of the elements contained within the ListView.
 * @since JavaFX 2.2
 */
public class CheckBoxListCell<T> extends ListCell<T> {

    /***************************************************************************
     *                                                                         *
     * Static cell factories                                                   *
     *                                                                         *
     **************************************************************************/

    
Creates a cell factory for use in ListView controls. When used in a ListView, the CheckBoxListCell is rendered with a CheckBox on the left-hand side of the ListView, with the text related to the list item taking up all remaining horizontal space. 
Params:
  • getSelectedProperty – A Callback that, given an object of type T (which is a value taken out of the ListView<T>.items list), will return an ObservableValue<Boolean> that represents whether the given item is selected or not. This ObservableValue will be bound bidirectionally (meaning that the CheckBox in the cell will set/unset this property based on user interactions, and the CheckBox will reflect the state of the ObservableValue, if it changes externally).
Type parameters:
  • <T> – The type of the elements contained within the ListView.
Returns:A Callback that will return a ListCell that is able to work on the type of element contained within the ListView items list.
/**
     * Creates a cell factory for use in ListView controls. When used in a
     * ListView, the {@link CheckBoxListCell} is rendered with a CheckBox on the
     * left-hand side of the ListView, with the text related to the list item
     * taking up all remaining horizontal space.
     *
     * @param <T> The type of the elements contained within the ListView.
     * @param getSelectedProperty A {@link Callback} that, given an object of
     *      type T (which is a value taken out of the
     *      {@code ListView<T>.items} list),
     *      will return an {@code ObservableValue<Boolean>} that represents
     *      whether the given item is selected or not. This ObservableValue will
     *      be bound bidirectionally (meaning that the CheckBox in the cell will
     *      set/unset this property based on user interactions, and the CheckBox
     *      will reflect the state of the ObservableValue, if it changes
     *      externally).
     * @return A {@link Callback} that will return a ListCell that is able to
     *      work on the type of element contained within the ListView items list.
     */
    public static <T> Callback<ListView<T>, ListCell<T>> forListView(
            final Callback<T, ObservableValue<Boolean>> getSelectedProperty) {
        return forListView(getSelectedProperty, CellUtils.<T>defaultStringConverter());
    }

    
Creates a cell factory for use in ListView controls. When used in a ListView, the CheckBoxListCell is rendered with a CheckBox on the left-hand side of the ListView, with the text related to the list item taking up all remaining horizontal space. 
Params:
  • getSelectedProperty – A Callback that, given an object of type T (which is a value taken out of the ListView<T>.items list), will return an ObservableValue<Boolean> that represents whether the given item is selected or not. This ObservableValue will be bound bidirectionally (meaning that the CheckBox in the cell will set/unset this property based on user interactions, and the CheckBox will reflect the state of the ObservableValue, if it changes externally).
  • converter – A StringConverter that, give an object of type T, will
     return a String that can be used to represent the object visually.
Type parameters:
  • <T> – The type of the elements contained within the ListView.
Returns:A Callback that will return a ListCell that is able to work on the type of element contained within the ListView.
/**
     * Creates a cell factory for use in ListView controls. When used in a
     * ListView, the {@link CheckBoxListCell} is rendered with a CheckBox on the
     * left-hand side of the ListView, with the text related to the list item
     * taking up all remaining horizontal space.
     *
     * @param <T> The type of the elements contained within the ListView.
     * @param getSelectedProperty A {@link Callback} that, given an object
     *      of type T (which is a value taken out of the
     *      {@code ListView<T>.items} list),
     *      will return an {@code ObservableValue<Boolean>} that represents
     *      whether the given item is selected or not. This ObservableValue will
     *      be bound bidirectionally (meaning that the CheckBox in the cell will
     *      set/unset this property based on user interactions, and the CheckBox
     *      will reflect the state of the ObservableValue, if it changes
     *      externally).
     * @param converter A StringConverter that, give an object of type T, will
     *      return a String that can be used to represent the object visually.
     * @return A {@link Callback} that will return a ListCell that is able to
     *      work on the type of element contained within the ListView.
     */
    public static <T> Callback<ListView<T>, ListCell<T>> forListView(
            final Callback<T, ObservableValue<Boolean>> getSelectedProperty,
            final StringConverter<T> converter) {
        return list -> new CheckBoxListCell<T>(getSelectedProperty, converter);
    }

    
                                                                        *
Fields                                                                  *
                                                                        *

/***************************************************************************
     *                                                                         *
     * Fields                                                                  *
     *                                                                         *
     **************************************************************************/

    private final CheckBox checkBox;

    private ObservableValue<Boolean> booleanProperty;



    /***************************************************************************
     *                                                                         *
     * Constructors                                                            *
     *                                                                         *
     **************************************************************************/

    
Creates a default CheckBoxListCell.

/**
     * Creates a default CheckBoxListCell.
     */
    public CheckBoxListCell() {
        this(null);
    }

    
Creates a default CheckBoxListCell.

Params:
  • getSelectedProperty – A Callback that will return an ObservableValue<Boolean> given an item from the ListView.
/**
     * Creates a default CheckBoxListCell.
     *
     * @param getSelectedProperty A {@link Callback} that will return an
     *      {@code ObservableValue<Boolean>} given an item from the ListView.
     */
    public CheckBoxListCell(
            final Callback<T, ObservableValue<Boolean>> getSelectedProperty) {
        this(getSelectedProperty, CellUtils.<T>defaultStringConverter());
    }

    
Creates a CheckBoxListCell with a custom string converter.

Params:
  • getSelectedProperty – A Callback that will return an ObservableValue<Boolean> given an item from the ListView.
  • converter – A StringConverter that, given an object of type T, will
     return a String that can be used to represent the object visually.
/**
     * Creates a CheckBoxListCell with a custom string converter.
     *
     * @param getSelectedProperty A {@link Callback} that will return an
     *      {@code ObservableValue<Boolean>} given an item from the ListView.
     * @param converter A StringConverter that, given an object of type T, will
     *      return a String that can be used to represent the object visually.
     */
    public CheckBoxListCell(
            final Callback<T, ObservableValue<Boolean>> getSelectedProperty,
            final StringConverter<T> converter) {
        this.getStyleClass().add("check-box-list-cell");
        setSelectedStateCallback(getSelectedProperty);
        setConverter(converter);

        this.checkBox = new CheckBox();

        setAlignment(Pos.CENTER_LEFT);
        setContentDisplay(ContentDisplay.LEFT);

        // by default the graphic is null until the cell stops being empty
        setGraphic(null);
    }


    
                                                                        *
Properties                                                              *
                                                                        *

/***************************************************************************
     *                                                                         *
     * Properties                                                              *
     *                                                                         *
     **************************************************************************/

    // --- converter
    private ObjectProperty<StringConverter<T>> converter =
            new SimpleObjectProperty<StringConverter<T>>(this, "converter");

    
The StringConverter property. 
Returns:the StringConverter property
/**
     * The {@link StringConverter} property.
     * @return the {@link StringConverter} property
     */
    public final ObjectProperty<StringConverter<T>> converterProperty() {
        return converter;
    }

    
Sets the StringConverter to be used in this cell. 
Params:
/**
     * Sets the {@link StringConverter} to be used in this cell.
     * @param value the {@link StringConverter}
     */
    public final void setConverter(StringConverter<T> value) {
        converterProperty().set(value);
    }

    
Returns the StringConverter used in this cell. 
Returns:the StringConverter used in this cell
/**
     * Returns the {@link StringConverter} used in this cell.
     * @return the {@link StringConverter} used in this cell
     */
    public final StringConverter<T> getConverter() {
        return converterProperty().get();
    }


    // --- selected state callback property
    private ObjectProperty<Callback<T, ObservableValue<Boolean>>>
            selectedStateCallback =
            new SimpleObjectProperty<Callback<T, ObservableValue<Boolean>>>(
            this, "selectedStateCallback");

    
Property representing the Callback that is bound to by the CheckBox shown on screen. 
Returns:the Callback that is bound to by the CheckBox shown on screen
/**
     * Property representing the {@link Callback} that is bound to by the
     * CheckBox shown on screen.
     * @return the {@link Callback} that is bound to by the CheckBox shown on
     * screen
     */
    public final ObjectProperty<Callback<T, ObservableValue<Boolean>>> selectedStateCallbackProperty() {
        return selectedStateCallback;
    }

    
Sets the Callback that is bound to by the CheckBox shown on screen. 
Params:
/**
     * Sets the {@link Callback} that is bound to by the CheckBox shown on screen.
     * @param value the {@link Callback}
     */
    public final void setSelectedStateCallback(Callback<T, ObservableValue<Boolean>> value) {
        selectedStateCallbackProperty().set(value);
    }

    
Returns the Callback that is bound to by the CheckBox shown on screen. 
Returns:the Callback that is bound to by the CheckBox shown on screen
/**
     * Returns the {@link Callback} that is bound to by the CheckBox shown on screen.
     * @return the {@link Callback} that is bound to by the CheckBox shown on screen
     */
    public final Callback<T, ObservableValue<Boolean>> getSelectedStateCallback() {
        return selectedStateCallbackProperty().get();
    }



    /***************************************************************************
     *                                                                         *
     * Public API                                                              *
     *                                                                         *
     **************************************************************************/

    
{@inheritDoc} 
/** {@inheritDoc} */
    @Override public void updateItem(T item, boolean empty) {
        super.updateItem(item, empty);

        if (! empty) {
            StringConverter<T> c = getConverter();
            Callback<T, ObservableValue<Boolean>> callback = getSelectedStateCallback();
            if (callback == null) {
                throw new NullPointerException(
                        "The CheckBoxListCell selectedStateCallbackProperty can not be null");
            }

            setGraphic(checkBox);
            setText(c != null ? c.toString(item) : (item == null ? "" : item.toString()));

            if (booleanProperty != null) {
                checkBox.selectedProperty().unbindBidirectional((BooleanProperty)booleanProperty);
            }
            booleanProperty = callback.call(item);
            if (booleanProperty != null) {
                checkBox.selectedProperty().bindBidirectional((BooleanProperty)booleanProperty);
            }
        } else {
            setGraphic(null);
            setText(null);
        }
    }
}