javafx.scene.control.cell

Class CheckBoxTreeCell<T>

java.lang.Object

<any>

javafx.scene.control.cell.DefaultTreeCell<T>

javafx.scene.control.cell.CheckBoxTreeCell<T>

Type Parameters:

T - The type of the elements contained within the TreeView TreeItem instances.

public class CheckBoxTreeCell<T>
extends DefaultTreeCell<T>

A class containing a TreeCell implementation that draws a CheckBox node inside the cell, along with support for common interactions (discussed in more depth shortly).

To make creating TreeViews with CheckBoxes easier, a convenience class called CheckBoxTreeItem is provided. It is highly recommended that developers use this class, rather than the regular TreeItem class, when constructing their TreeView tree structures. Refer to the CheckBoxTreeItem API documentation for an example on how these two classes can be combined.

When used in a TreeView, the CheckBoxCell is rendered with a CheckBox to the right of the 'disclosure node' (i.e. the arrow). The item stored in CheckBoxTreeItem#getValue() will then have the StringConverter called on it, and this text will take all remaining horizontal space. Additionally, by using CheckBoxTreeItem, the TreeView will automatically handle situations such as:

• Clicking on the CheckBox beside an item that has children will result in all children also becoming selected/unselected.
• Clicking on the CheckBox beside an item that has a parent will possibly toggle the state of the parent. For example, if you select a single child, the parent will become indeterminate (indicating partial selection of children). If you proceed to select all children, the parent will then show that it too is selected. This is recursive, with all parent nodes updating as expected.

If it is decided that using CheckBoxTreeItem is not desirable, then it is necessary to call one of the constructors where a Callback is provided that can return an ObservableValue<Boolean> given a TreeItem instance. This ObservableValue<Boolean> should represent the boolean state of the given TreeItem.

Note that the CheckBoxTreeCell 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.

Since:

JavaFX 2.2

Property Summary

Type	Property and Description
<any>	converter The StringConverter property.
<any>	selectedStateCallback Property representing the Callback that is bound to by the CheckBox shown on screen.

Field Summary

Fields

Modifier and Type	Field and Description
private <any>	booleanProperty
private CheckBox	checkBox * Fields * *
private <any>	converter * Properties * *
private BooleanProperty	indeterminateProperty
private <any>	selectedStateCallback

Constructor Summary

Constructors

Modifier	Constructor and Description
	CheckBoxTreeCell() Creates a default CheckBoxTreeCell that assumes the TreeView is constructed with CheckBoxTreeItem instances, rather than the default TreeItem.
	CheckBoxTreeCell(<any> getSelectedProperty) Creates a CheckBoxTreeCell for use in a TreeView control via a cell factory.
	CheckBoxTreeCell(<any> getSelectedProperty, <any> converter) Creates a CheckBoxTreeCell for use in a TreeView control via a cell factory.
private	CheckBoxTreeCell(<any> getSelectedProperty, <any> converter, <any> getIndeterminateProperty)

Method Summary

Modifier and Type	Method and Description
<any>	converterProperty() The StringConverter property.
static <T> <any>	forTreeView() Creates a cell factory for use in a TreeView control, although there is a major assumption when used in a TreeView: this cell factory assumes that the TreeView root, and all children are instances of CheckBoxTreeItem, rather than the default TreeItem class that is used normally.
static <T> <any>	forTreeView(<any> getSelectedProperty) Creates a cell factory for use in a TreeView control.
static <T> <any>	forTreeView(<any> getSelectedProperty, <any> converter) Creates a cell factory for use in a TreeView control.
<any>	getConverter() Returns the StringConverter used in this cell.
<any>	getSelectedStateCallback() Returns the Callback that is bound to by the CheckBox shown on screen.
<any>	selectedStateCallbackProperty() Property representing the Callback that is bound to by the CheckBox shown on screen.
void	setConverter(<any> value) Sets the StringConverter to be used in this cell.
void	setSelectedStateCallback(<any> value) Sets the Callback that is bound to by the CheckBox shown on screen.
(package private) void	updateDisplay(T item, boolean empty)
void	updateItem(T item, boolean empty)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Property Detail

converter

public final <any> converterProperty

The StringConverter property.

Returns:

the StringConverter property

selectedStateCallback

public final <any> selectedStateCallbackProperty

Property representing the Callback that is bound to by the CheckBox shown on screen.

See Also:

getSelectedStateCallback(), #setSelectedStateCallback()

Field Detail

checkBox

private final CheckBox checkBox

* Fields * *

booleanProperty

private <any> booleanProperty

indeterminateProperty

private BooleanProperty indeterminateProperty

converter

private <any> converter

* Properties * *

selectedStateCallback

private <any> selectedStateCallback

Constructor Detail

CheckBoxTreeCell

public CheckBoxTreeCell()

Creates a default CheckBoxTreeCell that assumes the TreeView is constructed with CheckBoxTreeItem instances, rather than the default TreeItem. By using CheckBoxTreeItem, it will internally manage the selected and indeterminate state of each item in the tree.

CheckBoxTreeCell

public CheckBoxTreeCell(<any> getSelectedProperty)

Creates a CheckBoxTreeCell for use in a TreeView control via a cell factory. Unlike CheckBoxTreeCell(), this method does not assume that all TreeItem instances in the TreeView are CheckBoxTreeItem.

To call this method, it is necessary to provide a Callback that, given an object of type TreeItem<T>, will return an ObservableValue<Boolean> that represents whether the given item is selected or not. This ObservableValue<Boolean> 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).

If the items are not CheckBoxTreeItem instances, it becomes the developers responsibility to handle updating the state of parent and children TreeItems. This means that, given a TreeItem, this class will simply toggles the ObservableValue<Boolean> that is provided, and no more. Of course, this functionality can then be implemented externally by adding observers to the ObservableValue<Boolean>, and toggling the state of other properties as necessary.

Parameters:

getSelectedProperty - A Callback that will return an ObservableValue<Boolean> that represents whether the given item is selected or not.

CheckBoxTreeCell

public CheckBoxTreeCell(<any> getSelectedProperty,
                        <any> converter)

Creates a CheckBoxTreeCell for use in a TreeView control via a cell factory. Unlike CheckBoxTreeCell(), this method does not assume that all TreeItem instances in the TreeView are CheckBoxTreeItem.

To call this method, it is necessary to provide a Callback that, given an object of type TreeItem<T>, will return an ObservableValue<Boolean> that represents whether the given item is selected or not. This ObservableValue<Boolean> 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).

If the items are not CheckBoxTreeItem instances, it becomes the developers responsibility to handle updating the state of parent and children TreeItems. This means that, given a TreeItem, this class will simply toggles the ObservableValue<Boolean> that is provided, and no more. Of course, this functionality can then be implemented externally by adding observers to the ObservableValue<Boolean>, and toggling the state of other properties as necessary.

Parameters:

getSelectedProperty - A Callback that will return an ObservableValue<Boolean> that represents whether the given item is selected or not.

converter - A StringConverter that, give an object of type TreeItem<T>, will return a String that can be used to represent the object visually.

CheckBoxTreeCell

private CheckBoxTreeCell(<any> getSelectedProperty,
                         <any> converter,
                         <any> getIndeterminateProperty)

Method Detail

forTreeView

public static <T> <any> forTreeView()

Creates a cell factory for use in a TreeView control, although there is a major assumption when used in a TreeView: this cell factory assumes that the TreeView root, and all children are instances of CheckBoxTreeItem, rather than the default TreeItem class that is used normally.

When used in a TreeView, the CheckBoxCell is rendered with a CheckBox to the right of the 'disclosure node' (i.e. the arrow). The item stored in CheckBoxTreeItem#getValue() will then have the StringConverter called on it, and this text will take all remaining horizontal space. Additionally, by using CheckBoxTreeItem, the TreeView will automatically handle situations such as:

• Clicking on the CheckBox beside an item that has children will result in all children also becoming selected/unselected.
• Clicking on the CheckBox beside an item that has a parent will possibly toggle the state of the parent. For example, if you select a single child, the parent will become indeterminate (indicating partial selection of children). If you proceed to select all children, the parent will then show that it too is selected. This is recursive, with all parent nodes updating as expected.

Unfortunately, due to limitations in Java, it is necessary to provide an explicit cast when using this method. For example:

 
 final TreeView<String> treeView = new TreeView<String>();
 treeView.setCellFactory(CheckBoxCell.<String>forTreeView());

Type Parameters:

T - The type of the elements contained within the CheckBoxTreeItem instances.

Returns:

A Callback that will return a TreeCell that is able to work on the type of element contained within the TreeView root, and all of its children (recursively).

forTreeView

public static <T> <any> forTreeView(<any> getSelectedProperty)

Creates a cell factory for use in a TreeView control. Unlike forTreeView(), this method does not assume that all TreeItem instances in the TreeView are CheckBoxTreeItem instances.

When used in a TreeView, the CheckBoxCell is rendered with a CheckBox to the right of the 'disclosure node' (i.e. the arrow). The item stored in CheckBoxTreeItem#getValue() will then have the StringConverter called on it, and this text will take all remaining horizontal space.

Unlike forTreeView(), this cell factory does not handle updating the state of parent or children TreeItems - it simply toggles the ObservableValue<Boolean> that is provided, and no more. Of course, this functionality can then be implemented externally by adding observers to the ObservableValue<Boolean>, and toggling the state of other properties as necessary.

Type Parameters:

T - The type of the elements contained within the TreeItem instances.

Parameters:

getSelectedProperty - A Callback that, given an object of type TreeItem<T>, will return an ObservableValue<Boolean> that represents whether the given item is selected or not. This ObservableValue<Boolean> 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).

Returns:

A Callback that will return a TreeCell that is able to work on the type of element contained within the TreeView root, and all of its children (recursively).

forTreeView

public static <T> <any> forTreeView(<any> getSelectedProperty,
                                    <any> converter)

Creates a cell factory for use in a TreeView control. Unlike forTreeView(), this method does not assume that all TreeItem instances in the TreeView are CheckBoxTreeItem.

When used in a TreeView, the CheckBoxCell is rendered with a CheckBox to the right of the 'disclosure node' (i.e. the arrow). The item stored in TreeItem#getValue() will then have the the StringConverter called on it, and this text will take all remaining horizontal space.

Unlike forTreeView(), this cell factory does not handle updating the state of parent or children TreeItems - it simply toggles the ObservableValue<Boolean> that is provided, and no more. Of course, this functionality can then be implemented externally by adding observers to the ObservableValue<Boolean>, and toggling the state of other properties as necessary.

Type Parameters:

T - The type of the elements contained within the TreeItem instances.

Parameters:

getSelectedProperty - A Callback that, given an object of type TreeItem<T>, will return an ObservableValue<Boolean> that represents whether the given item is selected or not. This ObservableValue<Boolean> 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).

converter - A StringConverter that, give an object of type TreeItem<T>, will return a String that can be used to represent the object visually. The default implementation in #forTreeView(Callback) is to simply call .toString() on all non-null items (and to just return an empty string in cases where the given item is null).

Returns:

A Callback that will return a TreeCell that is able to work on the type of element contained within the TreeView root, and all of its children (recursively).

converterProperty

public final <any> converterProperty()

The StringConverter property.

Returns:

the StringConverter property

setConverter

public final void setConverter(<any> value)

Sets the StringConverter to be used in this cell.

Parameters:

value - the StringConverter to be used in this cell

getConverter

public final <any> getConverter()

Returns the StringConverter used in this cell.

Returns:

the StringConverter used in this cell

selectedStateCallbackProperty

public final <any> selectedStateCallbackProperty()

Property representing the Callback that is bound to by the CheckBox shown on screen.

See Also:

getSelectedStateCallback(), #setSelectedStateCallback()

setSelectedStateCallback

public final void setSelectedStateCallback(<any> value)

Sets the Callback that is bound to by the CheckBox shown on screen.

Parameters:

value - the Callback that is bound to by the CheckBox shown on screen

getSelectedStateCallback

public final <any> getSelectedStateCallback()

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

updateItem

public void updateItem(T item,
                       boolean empty)

Overrides:

updateItem in class DefaultTreeCell<T>

updateDisplay

void updateDisplay(T item,
                   boolean empty)

Overrides:

updateDisplay in class DefaultTreeCell<T>