Package org.eclipse.swt.custom

Class CCombo

  • All Implemented Interfaces:
    Adaptable, Drawable
    public class CCombo
extends Composite
    The CCombo class represents a selectable user interface object that combines a text field and a list and issues notification when an item is selected from the list.

    CCombo was written to work around certain limitations in the native combo box. Specifically, on win32, the height of a CCombo can be set; attempts to set the height of a Combo are ignored. CCombo can be used anywhere that having the increased flexibility is more important than getting native L&F, but the decision should not be taken lightly. There is no is no strict requirement that CCombo look or behave the same as the native combo box.

    Note that although this class is a subclass of Composite, it does not make sense to add children to it, or set a layout on it.

    Styles:
    BORDER, READ_ONLY, FLAT
    Events:
    DefaultSelection, Modify, Selection, Verify
    Since:
    1.2

    • Field Detail

      • LIMIT

        public static final int LIMIT
        The maximum number of characters that can be entered into a text widget.

        Note that this value is platform dependent, based upon the native widget implementation.

        See Also:
        Constant Field Values

    • Constructor Detail

      • CCombo

        public CCombo​(Composite parent,
              int style)
        Constructs a new instance of this class given its parent and a style value describing its behavior and appearance.

        The style value is either one of the style constants defined in class SWT which is applicable to instances of this class, or must be built by bitwise OR'ing together (that is, using the int "|" operator) two or more of those SWT style constants. The class description lists the style constants that are applicable to the class. Style bits are also inherited from superclasses.

        Parameters:
        parent - a widget which will be the parent of the new instance (cannot be null)
        style - the style of widget to construct
        Throws:
        java.lang.IllegalArgumentException -
        • ERROR_NULL_ARGUMENT - if the parent is null
        SWTException -
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent
        See Also:
        SWT.BORDER, SWT.READ_ONLY, SWT.FLAT, Widget.getStyle()

    • Method Detail

      • getStyle

        public int getStyle()
        Description copied from class: Widget
        Returns the receiver's style information.

        Note that the value which is returned by this method may not match the value which was provided to the constructor when the receiver was created. This can occur when the underlying operating system does not support a particular combination of requested styles. For example, if the platform widget used to implement a particular SWT widget always has scroll bars, the result of calling this method would always have the SWT.H_SCROLL and SWT.V_SCROLL bits set.

        Overrides:
        getStyle in class Widget
        Returns:
        the style bits

      • getSelectionIndex

        public int getSelectionIndex()
        Returns the zero-relative index of the item which is currently selected in the receiver's list, or -1 if no item is selected.
        Returns:
        the index of the selected item
        Throws:
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

      • select

        public void select​(int index)
        Selects the item at the given zero-relative index in the receiver's list. If the item at the index was already selected, it remains selected. Indices that are out of range are ignored.
        Parameters:
        index - the index of the item to select
        Throws:
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

      • deselect

        public void deselect​(int index)
        Deselects the item at the given zero-relative index in the receiver's list. If the item at the index was already deselected, it remains deselected. Indices that are out of range are ignored.
        Parameters:
        index - the index of the item to deselect
        Throws:
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

      • deselectAll

        public void deselectAll()
        Deselects all selected items in the receiver's list.

        Note: To clear the selection in the receiver's text field, use clearSelection().

        Throws:
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
        See Also:
        clearSelection()

      • setSelection

        public void setSelection​(Point selection)
        Sets the selection in the receiver's text field to the range specified by the argument whose x coordinate is the start of the selection and whose y coordinate is the end of the selection.
        Parameters:
        selection - a point representing the new selection start and end
        Throws:
        java.lang.IllegalArgumentException -
        • ERROR_NULL_ARGUMENT - if the point is null
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

      • getSelection

        public Point getSelection()
        Returns a Point whose x coordinate is the start of the selection in the receiver's text field, and whose y coordinate is the end of the selection. The returned values are zero-relative. An "empty" selection as indicated by the the x and y coordinates having the same value.
        Returns:
        a point representing the selection start and end
        Throws:
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

      • setTextLimit

        public void setTextLimit​(int limit)
        Sets the maximum number of characters that the receiver's text field is capable of holding to be the argument.
        Parameters:
        limit - new text limit
        Throws:
        java.lang.IllegalArgumentException -
        • ERROR_CANNOT_BE_ZERO - if the limit is zero
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

      • getTextLimit

        public int getTextLimit()
        Returns the maximum number of characters that the receiver's text field is capable of holding. If this has not been changed by setTextLimit(), it will be the constant Combo.LIMIT.
        Returns:
        the text limit
        Throws:
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

      • getTextHeight

        public int getTextHeight()
        Returns the height of the receivers's text field.
        Returns:
        the text height
        Throws:
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
        Since:
        1.3

      • clearSelection

        public void clearSelection()
        Sets the selection in the receiver's text field to an empty selection starting just before the first character. If the text field is editable, this has the effect of placing the i-beam at the start of the text.

        Note: To clear the selected items in the receiver's list, use deselectAll().

        Throws:
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
        See Also:
        deselectAll()

      • add

        public void add​(java.lang.String string)
        Adds the argument to the end of the receiver's list.
        Parameters:
        string - the new item
        Throws:
        java.lang.IllegalArgumentException -
        • ERROR_NULL_ARGUMENT - if the string is null
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
        See Also:
        add(String,int)

      • add

        public void add​(java.lang.String string,
                int index)
        Adds the argument to the receiver's list at the given zero-relative index.

        Note: To add an item at the end of the list, use the result of calling getItemCount() as the index or use add(String).

        Parameters:
        string - the new item
        index - the index for the item
        Throws:
        java.lang.IllegalArgumentException -
        • ERROR_NULL_ARGUMENT - if the string is null
        • ERROR_INVALID_RANGE - if the index is not between 0 and the number of elements in the list (inclusive)
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
        See Also:
        add(String)

      • remove

        public void remove​(int index)
        Removes the item from the receiver's list at the given zero-relative index.
        Parameters:
        index - the index for the item
        Throws:
        java.lang.IllegalArgumentException -
        • ERROR_INVALID_RANGE - if the index is not between 0 and the number of elements in the list minus 1 (inclusive)
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

      • remove

        public void remove​(int start,
                   int end)
        Removes the items from the receiver's list which are between the given zero-relative start and end indices (inclusive).
        Parameters:
        start - the start of the range
        end - the end of the range
        Throws:
        java.lang.IllegalArgumentException -
        • ERROR_INVALID_RANGE - if either the start or end are not between 0 and the number of elements in the list minus 1 (inclusive)
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

      • remove

        public void remove​(java.lang.String string)
        Searches the receiver's list starting at the first item until an item is found that is equal to the argument, and removes that item from the list.
        Parameters:
        string - the item to remove
        Throws:
        java.lang.IllegalArgumentException -
        • ERROR_NULL_ARGUMENT - if the string is null
        • ERROR_INVALID_ARGUMENT - if the string is not found in the list
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

      • removeAll

        public void removeAll()
        Removes all of the items from the receiver's list and clear the contents of receiver's text field.

        Throws:
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

      • setItem

        public void setItem​(int index,
                    java.lang.String string)
        Sets the text of the item in the receiver's list at the given zero-relative index to the string argument. This is equivalent to remove'ing the old item at the index, and then add'ing the new item at that index.
        Parameters:
        index - the index for the item
        string - the new text for the item
        Throws:
        java.lang.IllegalArgumentException -
        • ERROR_INVALID_RANGE - if the index is not between 0 and the number of elements in the list minus 1 (inclusive)
        • ERROR_NULL_ARGUMENT - if the string is null
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

      • setItems

        public void setItems​(java.lang.String... items)
        Sets the receiver's list to be the given array of items.
        Parameters:
        items - the array of items
        Throws:
        java.lang.IllegalArgumentException -
        • ERROR_NULL_ARGUMENT - if the items array is null
        • ERROR_INVALID_ARGUMENT - if an item in the items array is null
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

      • getItem

        public java.lang.String getItem​(int index)
        Returns the item at the given, zero-relative index in the receiver's list. Throws an exception if the index is out of range.
        Parameters:
        index - the index of the item to return
        Returns:
        the item at the given index
        Throws:
        java.lang.IllegalArgumentException -
        • ERROR_INVALID_RANGE - if the index is not between 0 and the number of elements in the list minus 1 (inclusive)
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

      • getItemCount

        public int getItemCount()
        Returns the number of items contained in the receiver's list.
        Returns:
        the number of items
        Throws:
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

      • getItemHeight

        public int getItemHeight()
        Returns the height of the area which would be used to display one of the items in the receiver's list.
        Returns:
        the height of one item
        Throws:
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

      • getItems

        public java.lang.String[] getItems()
        Returns an array of Strings which are the items in the receiver's list.

        Note: This is not the actual structure used by the receiver to maintain its list of items, so modifying the array will not affect the receiver.

        Returns:
        the items in the receiver's list
        Throws:
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

      • setVisibleItemCount

        public void setVisibleItemCount​(int count)
        Sets the number of items that are visible in the drop down portion of the receiver's list.
        Parameters:
        count - the new number of items to be visible
        Throws:
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

      • getVisibleItemCount

        public int getVisibleItemCount()
        Gets the number of items that are visible in the drop down portion of the receiver's list.
        Returns:
        the number of items that are visible
        Throws:
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

      • setListVisible

        public void setListVisible​(boolean visible)
        Marks the receiver's list as visible if the argument is true, and marks it invisible otherwise.

        If one of the receiver's ancestors is not visible or some other condition makes the receiver not visible, marking it visible may not actually cause it to be displayed.

        Parameters:
        visible - the new visibility state
        Throws:
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

      • getListVisible

        public boolean getListVisible()
        Returns true if the receiver's list is visible, and false otherwise.

        If one of the receiver's ancestors is not visible or some other condition makes the receiver not visible, this method may still indicate that it is considered visible even though it may not actually be showing.

        Returns:
        the receiver's list's visibility state
        Throws:
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

      • indexOf

        public int indexOf​(java.lang.String string)
        Searches the receiver's list starting at the first item (index 0) until an item is found that is equal to the argument, and returns the index of that item. If no item is found, returns -1.
        Parameters:
        string - the search item
        Returns:
        the index of the item
        Throws:
        java.lang.IllegalArgumentException -
        • ERROR_NULL_ARGUMENT - if the string is null
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

      • indexOf

        public int indexOf​(java.lang.String string,
                   int start)
        Searches the receiver's list starting at the given, zero-relative index until an item is found that is equal to the argument, and returns the index of that item. If no item is found or the starting index is out of range, returns -1.
        Parameters:
        string - the search item
        start - the zero-relative index at which to begin the search
        Returns:
        the index of the item
        Throws:
        java.lang.IllegalArgumentException -
        • ERROR_NULL_ARGUMENT - if the string is null
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

      • setText

        public void setText​(java.lang.String string)
        Sets the contents of the receiver's text field to the given string.

        Note: The text field in a Combo is typically only capable of displaying a single line of text. Thus, setting the text to a string containing line breaks or other special characters will probably cause it to display incorrectly.

        Parameters:
        string - the new text
        Throws:
        java.lang.IllegalArgumentException -
        • ERROR_NULL_ARGUMENT - if the string is null
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

      • getText

        public java.lang.String getText()
        Returns a string containing a copy of the contents of the receiver's text field.
        Returns:
        the receiver's text
        Throws:
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

      • setEditable

        public void setEditable​(boolean editable)
        Sets the editable state.
        Parameters:
        editable - the new editable state
        Throws:
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

      • getEditable

        public boolean getEditable()
        Gets the editable state.
        Returns:
        whether or not the receiver is editable
        Throws:
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

      • computeSize

        public Point computeSize​(int wHint,
                         int hHint,
                         boolean changed)
        Description copied from class: Control
        Returns the preferred size of the receiver.

        The preferred size of a control is the size that it would best be displayed at. The width hint and height hint arguments allow the caller to ask a control questions such as "Given a particular width, how high does the control need to be to show all of the contents?" To indicate that the caller does not wish to constrain a particular dimension, the constant SWT.DEFAULT is passed for the hint.

        If the changed flag is true, it indicates that the receiver's contents have changed, therefore any caches that a layout manager containing the control may have been keeping need to be flushed. When the control is resized, the changed flag will be false, so layout manager caches can be retained.

        Overrides:
        computeSize in class Composite
        Parameters:
        wHint - the width hint (can be SWT.DEFAULT)
        hHint - the height hint (can be SWT.DEFAULT)
        changed - true if the control's contents have changed, and false otherwise
        Returns:
        the preferred size of the control.
        See Also:
        Layout, Control.getBorderWidth(), Control.getBounds(), Control.getSize(), Control.pack(boolean), "computeTrim, getClientArea for controls that implement them"

      • addSelectionListener

        public void addSelectionListener​(SelectionListener listener)
        Adds the listener to the collection of listeners who will be notified when the user changes the receiver's selection, by sending it one of the messages defined in the SelectionListener interface.

        widgetSelected is called when the combo's list selection changes. widgetDefaultSelected is typically called when ENTER is pressed the combo's text area.

        Parameters:
        listener - the listener which should be notified when the user changes the receiver's selection
        Throws:
        java.lang.IllegalArgumentException -
        • ERROR_NULL_ARGUMENT - if the listener is null
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
        See Also:
        SelectionListener, removeSelectionListener(org.eclipse.swt.events.SelectionListener), SelectionEvent

      • removeSelectionListener

        public void removeSelectionListener​(SelectionListener listener)
        Removes the listener from the collection of listeners who will be notified when the user changes the receiver's selection.
        Parameters:
        listener - the listener which should no longer be notified
        Throws:
        java.lang.IllegalArgumentException -
        • ERROR_NULL_ARGUMENT - if the listener is null
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
        See Also:
        SelectionListener, addSelectionListener(org.eclipse.swt.events.SelectionListener)

      • addModifyListener

        public void addModifyListener​(ModifyListener listener)
        Adds the listener to the collection of listeners who will be notified when the receiver's text is modified, by sending it one of the messages defined in the ModifyListener interface.
        Parameters:
        listener - the listener which should be notified
        Throws:
        java.lang.IllegalArgumentException -
        • ERROR_NULL_ARGUMENT - if the listener is null
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
        See Also:
        ModifyListener, removeModifyListener(org.eclipse.swt.events.ModifyListener)

      • removeModifyListener

        public void removeModifyListener​(ModifyListener listener)
        Removes the listener from the collection of listeners who will be notified when the receiver's text is modified.
        Parameters:
        listener - the listener which should no longer be notified
        Throws:
        java.lang.IllegalArgumentException -
        • ERROR_NULL_ARGUMENT - if the listener is null
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
        See Also:
        ModifyListener, addModifyListener(org.eclipse.swt.events.ModifyListener)

      • addVerifyListener

        public void addVerifyListener​(VerifyListener listener)
        Adds the listener to the collection of listeners who will be notified when the receiver's text is verified, by sending it one of the messages defined in the VerifyListener interface.
        Parameters:
        listener - the listener which should be notified
        Throws:
        java.lang.IllegalArgumentException -
        • ERROR_NULL_ARGUMENT - if the listener is null
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
        See Also:
        VerifyListener, removeVerifyListener(org.eclipse.swt.events.VerifyListener)

      • removeVerifyListener

        public void removeVerifyListener​(VerifyListener listener)
        Removes the listener from the collection of listeners who will be notified when the control is verified.
        Parameters:
        listener - the listener which should no longer be notified
        Throws:
        java.lang.IllegalArgumentException -
        • ERROR_NULL_ARGUMENT - if the listener is null
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
        See Also:
        VerifyListener, addVerifyListener(org.eclipse.swt.events.VerifyListener)

      • getChildren

        public Control[] getChildren()
        Description copied from class: Composite
        Returns a (possibly empty) array containing the receiver's children. Children are returned in the order that they are drawn. The topmost control appears at the beginning of the array. Subsequent controls draw beneath this control and appear later in the array.

        Note: This is not the actual structure used by the receiver to maintain its list of children, so modifying the array will not affect the receiver.

        Overrides:
        getChildren in class Composite
        Returns:
        an array of children
        See Also:
        Control.moveAbove(org.eclipse.swt.widgets.Control), Control.moveBelow(org.eclipse.swt.widgets.Control)

      • setLayout

        public void setLayout​(Layout layout)
        Sets the layout which is associated with the receiver to be the argument which may be null.

        Note: No Layout can be set on this Control because it already manages the size and position of its children.

        Overrides:
        setLayout in class Composite
        Parameters:
        layout - the receiver's new layout or null
        Throws:
        SWTException -
        • ERROR_WIDGET_DISPOSED - if the receiver has been disposed
        • ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

      • getAdapter

        public <T> T getAdapter​(java.lang.Class<T> adapter)
        Description copied from class: Widget
        Implementation of the Adaptable interface.

        IMPORTANT: This method is not part of the RWT public API. It is marked public only so that it can be shared within the packages provided by RWT. It should never be accessed from application code.

        Specified by:
        getAdapter in interface Adaptable
        Overrides:
        getAdapter in class Composite
        Parameters:
        adapter - the lookup class
        Returns:
        an object that can be cast to the given class or null if there is no adapter associated with the given class.