com.google.gwt.user.client.ui
Class ComplexPanel

java.lang.Object
  com.google.gwt.user.client.ui.UIObject
      com.google.gwt.user.client.ui.Widget
          com.google.gwt.user.client.ui.Panel
              com.google.gwt.user.client.ui.ComplexPanel

All Implemented Interfaces:

EventListener, HasWidgets, IndexedPanel

Direct Known Subclasses:

AbsolutePanel, CellPanel, DeckPanel, FlowPanel, HTMLPanel, StackPanel

public abstract class ComplexPanel
extends Panel
implements IndexedPanel

Abstract base class for panels that can contain multiple child widgets.

Constructor Summary

ComplexPanel()

Method Summary

protected void	add(Widget child, Element container) Adds a new child widget to the panel, attaching its Element to the specified container Element.
protected int	adjustIndex(Widget child, int beforeIndex) Adjusts beforeIndex to account for the possibility that the given widget is already a child of this panel.
protected void	checkIndexBoundsForAccess(int index) Checks that index is in the range [0, getWidgetCount()), which is the valid range on accessible indexes.
protected void	checkIndexBoundsForInsertion(int index) Checks that index is in the range [0, getWidgetCount()], which is the valid range for indexes on an insertion.
protected WidgetCollection	getChildren() Gets the list of children contained in this panel.
Widget	getWidget(int index) Gets the child widget at the specified index.
int	getWidgetCount() Gets the number of child widgets in this panel.
int	getWidgetIndex(Widget child) Gets the index of the specified child widget.
protected void	insert(Widget child, Element container, int beforeIndex) Deprecated. Use insert(Widget, Element, int, boolean).
protected void	insert(Widget child, Element container, int beforeIndex, boolean domInsert) Insert a new child Widget into this Panel at a specified index, attaching its Element to the specified container Element.
java.util.Iterator	iterator() Gets an iterator for the contained widgets.
boolean	remove(int index) Removes the widget at the specified index.
boolean	remove(Widget w) Removes a child widget.

Methods inherited from class com.google.gwt.user.client.ui.Panel

add, adopt, adopt, clear, disown, doAttachChildren, doDetachChildren, onLoad, onUnload, orphan

Methods inherited from class com.google.gwt.user.client.ui.Widget

getParent, isAttached, onAttach, onBrowserEvent, onDetach, removeFromParent, setElement

Methods inherited from class com.google.gwt.user.client.ui.UIObject

addStyleDependentName, addStyleName, getAbsoluteLeft, getAbsoluteTop, getElement, getOffsetHeight, getOffsetWidth, getStyleElement, getStyleName, getStyleName, getStylePrimaryName, getStylePrimaryName, getTitle, isVisible, isVisible, removeStyleDependentName, removeStyleName, setHeight, setPixelSize, setSize, setStyleName, setStyleName, setStyleName, setStylePrimaryName, setStylePrimaryName, setTitle, setVisible, setVisible, setWidth, sinkEvents, toString, unsinkEvents

Methods inherited from class java.lang.Object

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

Constructor Detail

ComplexPanel

public ComplexPanel()

Method Detail

getWidget

public Widget getWidget(int index)

Description copied from interface: IndexedPanel

Gets the child widget at the specified index.

Specified by:

getWidget in interface IndexedPanel

Parameters:

index - the child widget's index

Returns:

the child widget

getWidgetCount

public int getWidgetCount()

Description copied from interface: IndexedPanel

Gets the number of child widgets in this panel.

Specified by:

getWidgetCount in interface IndexedPanel

Returns:

the number of children

getWidgetIndex

public int getWidgetIndex(Widget child)

Description copied from interface: IndexedPanel

Gets the index of the specified child widget.

Specified by:

getWidgetIndex in interface IndexedPanel

Parameters:

child - the widget to be found

Returns:

the widget's index, or -1 if it is not a child of this panel

iterator

public java.util.Iterator iterator()

Description copied from interface: HasWidgets

Gets an iterator for the contained widgets. This iterator is required to implement Iterator.remove().

Specified by:

iterator in interface HasWidgets

remove

public boolean remove(int index)

Description copied from interface: IndexedPanel

Removes the widget at the specified index.

Specified by:

remove in interface IndexedPanel

Parameters:

index - the index of the widget to be removed

Returns:

false if the widget is not present

remove

public boolean remove(Widget w)

Description copied from class: Panel

Removes a child widget.

How to Override this Method

There are several important things that must take place in the correct order to properly remove a Widget from a Panel. Not all of these steps will be relevant to every Panel, but all of the steps must be considered.

1. Validate: Make sure this Panel is actually the parent of the child Widget; return false if it is not.
2. Orphan: Call Panel.orphan(Widget) first while the child Widget is still attached.
3. Physical Detach: Adjust the DOM to account for the removal of the child Widget. The Widget's Element must be physically removed from the DOM.
4. Logical Detach: Update the Panel's state variables to reflect the removal of the child Widget. Example: the Widget is removed from the Panel's WidgetCollection.

Specified by:

remove in interface HasWidgets

Specified by:

remove in class Panel

Parameters:

w - the widget to be removed

Returns:

true if the child was present

add

protected void add(Widget child,
                   Element container)

Adds a new child widget to the panel, attaching its Element to the specified container Element.

Parameters:

child - the child widget to be added

container - the element within which the child will be contained

adjustIndex

protected int adjustIndex(Widget child,
                          int beforeIndex)

Adjusts beforeIndex to account for the possibility that the given widget is already a child of this panel.

Parameters:

child - the widget that might be an existing child

beforeIndex - the index at which it will be added to this panel

Returns:

the modified index

checkIndexBoundsForAccess

protected void checkIndexBoundsForAccess(int index)

Checks that index is in the range [0, getWidgetCount()), which is the valid range on accessible indexes.

Parameters:

index - the index being accessed

checkIndexBoundsForInsertion

protected void checkIndexBoundsForInsertion(int index)

Checks that index is in the range [0, getWidgetCount()], which is the valid range for indexes on an insertion.

Parameters:

index - the index where insertion will occur

getChildren

protected WidgetCollection getChildren()

Gets the list of children contained in this panel.

Returns:

a collection of child widgets

insert

protected void insert(Widget child,
                      Element container,
                      int beforeIndex)

Deprecated. Use insert(Widget, Element, int, boolean).

This method was used by subclasses to insert a new child Widget. It is now deprecated because it was ambiguous whether the child should be appended to container element versus inserted into container at beforeIndex. Use insert(Widget, Element, int, boolean), which clarifies this ambiguity.

insert

protected void insert(Widget child,
                      Element container,
                      int beforeIndex,
                      boolean domInsert)

Insert a new child Widget into this Panel at a specified index, attaching its Element to the specified container Element. The child Element will either be attached to the container at the same index, or simply appended to the container, depending on the value of domInsert.

Parameters:

child - the child Widget to be added

container - the Element within which child will be contained

beforeIndex - the index before which child will be inserted

domInsert - if true, insert child into container at beforeIndex; otherwise append child to the end of container.