Module javafx.controls
Package javafx.scene.control.cell

Class ComboBoxTreeCell<T>

  • Type Parameters:
    T - The type of the TreeItems contained within the TreeView.
    All Implemented Interfaces:
    Styleable, EventTarget, Skinnable
    public class ComboBoxTreeCell<T>
extends TreeCell<T>
    A class containing a TreeCell implementation that draws a ComboBox node inside the cell.

    By default, the ComboBoxTreeCell is rendered as a Label when not being edited, and as a ComboBox when in editing mode. The ComboBox will, by default, stretch to fill the entire tree cell.

    To create a ComboBoxTreeCell, it is necessary to provide zero or more items that will be shown to the user when the ComboBox menu is showing. These items must be of the same type as the TreeView TreeItems, such that upon selection, they replace the existing value in the TreeItem.valueProperty().

    Since:
    JavaFX 2.2

    • Constructor Detail

      • ComboBoxTreeCell

        public ComboBoxTreeCell()
        Creates a default ComboBoxTreeCell with an empty items list.

      • ComboBoxTreeCell

        @SafeVarargs
public ComboBoxTreeCell​(T... items)
        Creates a default ComboBoxTreeCell instance with the given items being used to populate the ComboBox when it is shown.
        Parameters:
        items - The items to show in the ComboBox popup menu when selected by the user.

      • ComboBoxTreeCell

        @SafeVarargs
public ComboBoxTreeCell​(StringConverter<T> converter,
                        T... items)
        Creates a ComboBoxTreeCell instance with the given items being used to populate the ComboBox when it is shown, and the StringConverter being used to convert the item in to a user-readable form.
        Parameters:
        converter - A StringConverter that can convert an item of type T into a user-readable string so that it may then be shown in the ComboBox popup menu.
        items - The items to show in the ComboBox popup menu when selected by the user.

      • ComboBoxTreeCell

        public ComboBoxTreeCell​(ObservableList<T> items)
        Creates a default ComboBoxTreeCell instance with the given items being used to populate the ComboBox when it is shown.
        Parameters:
        items - The items to show in the ComboBox popup menu when selected by the user.

      • ComboBoxTreeCell

        public ComboBoxTreeCell​(StringConverter<T> converter,
                        ObservableList<T> items)
        Creates a ComboBoxTreeCell instance with the given items being used to populate the ComboBox when it is shown, and the StringConverter being used to convert the item in to a user-readable form.
        Parameters:
        converter - A StringConverter that can convert an item of type T into a user-readable string so that it may then be shown in the ComboBox popup menu.
        items - The items to show in the ComboBox popup menu when selected by the user.

    • Method Detail

      • forTreeView

        @SafeVarargs
public static <T> Callback<TreeView<T>,​TreeCell<T>> forTreeView​(T... items)
        Creates a ComboBox cell factory for use in TreeView controls. By default, the ComboBoxCell is rendered as a Label when not being edited, and as a ComboBox when in editing mode. The ComboBox will, by default, stretch to fill the entire tree cell.
        Type Parameters:
        T - The type of the elements contained within the TreeView.
        Parameters:
        items - Zero or more items that will be shown to the user when the ComboBox menu is showing. These items must be of the same type as the TreeView<T>, such that upon selection, they replace the existing value in the TreeItem value property.
        Returns:
        A Callback that will return a TreeCell that is able to work on the type of element contained within the TreeView.

      • forTreeView

        public static <T> Callback<TreeView<T>,​TreeCell<T>> forTreeView​(ObservableList<T> items)
        Creates a ComboBox cell factory for use in TreeView controls. By default, the ComboBoxCell is rendered as a Label when not being edited, and as a ComboBox when in editing mode. The ComboBox will, by default, stretch to fill the entire tree cell, excluding the space allocated to the tree cell indentation and disclosure node(i.e. the arrow).
        Type Parameters:
        T - The type of the TreeItem elements contained within the TreeView.
        Parameters:
        items - An ObservableList containing zero or more items that will be shown to the user when the ComboBox menu is showing. These items must be of the same type as the TreeView generic type, such that upon selection, they replace the existing value in the TreeItem that is being edited (as noted in the TreeView.editingItemProperty().
        Returns:
        A Callback that will return a TreeCell that is able to work on the type of element contained within the TreeView.

      • forTreeView

        @SafeVarargs
public static <T> Callback<TreeView<T>,​TreeCell<T>> forTreeView​(StringConverter<T> converter,
                                                                      T... items)
        Creates a ComboBox cell factory for use in TreeView controls. By default, the ComboBoxCell is rendered as a Label when not being edited, and as a ComboBox when in editing mode. The ComboBox will, by default, stretch to fill the entire tree cell.
        Type Parameters:
        T - The type of the elements contained within the TreeView.
        Parameters:
        converter - A StringConverter to convert the given item (of type T) to a String for displaying to the user.
        items - Zero or more items that will be shown to the user when the ComboBox menu is showing. These items must be of the same type as the TreeView<T>, such that upon selection, they replace the existing value in the TreeItem value property.
        Returns:
        A Callback that will return a TreeCell that is able to work on the type of element contained within the TreeView.

      • forTreeView

        public static <T> Callback<TreeView<T>,​TreeCell<T>> forTreeView​(StringConverter<T> converter,
                                                                      ObservableList<T> items)
        Creates a ComboBox cell factory for use in TreeView controls. By default, the ComboBoxCell is rendered as a Label when not being edited, and as a ComboBox when in editing mode. The ComboBox will, by default, stretch to fill the entire tree cell.
        Type Parameters:
        T - The type of the elements contained within the TreeView.
        Parameters:
        converter - A StringConverter to convert the given item (of type T) to a String for displaying to the user.
        items - An ObservableList containing zero or more items that will be shown to the user when the ComboBox menu is showing. These items must be of the same type as the TreeView generic type, such that upon selection, they replace the existing value in the TreeItem that is being edited (as noted in the TreeView.editingItemProperty().
        Returns:
        A Callback that will return a TreeCell that is able to work on the type of element contained within the TreeView.

      • setComboBoxEditable

        public final void setComboBoxEditable​(boolean value)
        Configures the ComboBox to be editable (to allow user input outside of the options provide in the dropdown list).
        Parameters:
        value - the editable value to be set for this ComboBox

      • isComboBoxEditable

        public final boolean isComboBoxEditable()
        Returns true if the ComboBox is editable.
        Returns:
        true if the ComboBox is editable

      • getItems

        public ObservableList<T> getItems()
        Returns the items to be displayed in the ComboBox when it is showing.
        Returns:
        the items to be displayed in this ComboBox when it is showing

      • startEdit

        public void startEdit()
        Call this function to transition from a non-editing state into an editing state, if the cell is editable. If this cell is already in an editing state, it will stay in it.
        Overrides:
        startEdit in class TreeCell<T>

      • cancelEdit

        public void cancelEdit()
        Call this function to transition from an editing state into a non-editing state, without saving any user input.
        Overrides:
        cancelEdit in class TreeCell<T>

      • updateItem

        public void updateItem​(T item,
                       boolean empty)
        The updateItem method should not be called by developers, but it is the best method for developers to override to allow for them to customise the visuals of the cell. To clarify, developers should never call this method in their code (they should leave it up to the UI control, such as the ListView control) to call this method. However, the purpose of having the updateItem method is so that developers, when specifying custom cell factories (again, like the ListView cell factory), the updateItem method can be overridden to allow for complete customisation of the cell.

        It is very important that subclasses of Cell override the updateItem method properly, as failure to do so will lead to issues such as blank cells or cells with unexpected content appearing within them. Here is an example of how to properly override the updateItem method: 

         protected void updateItem(T item, boolean empty) {
     super.updateItem(item, empty);

     if (empty || item == null) {
         setText(null);
         setGraphic(null);
     } else {
         setText(item.toString());
     }
 }

        Note in this code sample two important points:

        1. We call the super.updateItem(T, boolean) method. If this is not done, the item and empty properties are not correctly set, and you are likely to end up with graphical issues.
        2. We test for the empty condition, and if true, we set the text and graphic properties to null. If we do not do this, it is almost guaranteed that end users will see graphical artifacts in cells unexpectedly.
        Parameters:
        item - The new item for the cell.
        empty - whether or not this cell represents data from the list. If it is empty, then it does not represent any domain data, but is a cell being used to render an "empty" row.