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

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
                  com.google.gwt.user.client.ui.DeckLayoutPanel

All Implemented Interfaces:

HasAttachHandlers, HasHandlers, EventListener, AcceptsOneWidget, AnimatedLayout, HasVisibility, HasWidgets, HasWidgets.ForIsWidget, IndexedPanel, IndexedPanel.ForIsWidget, InsertPanel, InsertPanel.ForIsWidget, IsWidget, ProvidesResize, RequiresResize, java.lang.Iterable<Widget>

public class DeckLayoutPanel
extends ComplexPanel
implements AnimatedLayout, RequiresResize, ProvidesResize, InsertPanel.ForIsWidget, AcceptsOneWidget

A panel that displays all of its child widgets in a 'deck', where only one can be visible at a time. It is used by TabLayoutPanel.

This widget will only work in standards mode, which requires that the HTML page in which it is run have an explicit <!DOCTYPE> declaration.

Once a widget has been added to a DeckPanel, its visibility, width, and height attributes will be manipulated. When the widget is removed from the DeckPanel, it will be visible, and its width and height attributes will be cleared.

DeckLayoutPanel

public DeckLayoutPanel()

Creates an empty deck panel.

add

public void add(Widget w)

Description copied from class: Panel

Adds a child widget.

How to Override this Method

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

1. Validate: Perform any sanity checks to ensure the Panel can accept a new Widget. Examples: checking for a valid index on insertion; checking that the Panel is not full if there is a max capacity.
2. Adjust for Reinsertion: Some Panels need to handle the case where the Widget is already a child of this Panel. Example: when performing a reinsert, the index might need to be adjusted to account for the Widget's removal. See ComplexPanel.adjustIndex(Widget, int).
3. Detach Child: Remove the Widget from its existing parent, if any. Most Panels will simply call Widget.removeFromParent() on the Widget.
4. Logical Attach: Any state variables of the Panel should be updated to reflect the addition of the new Widget. Example: the Widget is added to the Panel's WidgetCollection at the appropriate index.
5. Physical Attach: The Widget's Element must be physically attached to the Panel's Element, either directly or indirectly.
6. Adopt: Call Panel.adopt(Widget) to finalize the add as the very last step.

Specified by:

add in interface HasWidgets

Specified by:

add in interface InsertPanel

Overrides:

add in class Panel

Parameters:

w - the widget to be added

See Also:

HasWidgets.add(Widget)

animate

public void animate(int duration)

Description copied from interface: AnimatedLayout

Layout children, animating over the specified period of time.

Specified by:

animate in interface AnimatedLayout

Parameters:

duration - the animation duration, in milliseconds

animate

public void animate(int duration,
                    Layout.AnimationCallback callback)

Description copied from interface: AnimatedLayout

Layout children, animating over the specified period of time.

This method provides a callback that will be informed of animation updates. This can be used to create more complex animation effects.

Specified by:

animate in interface AnimatedLayout

Parameters:

duration - the animation duration, in milliseconds

callback - the animation callback

forceLayout

public void forceLayout()

Description copied from interface: AnimatedLayout

Layout children immediately.

This is not normally necessary, unless you want to update child widgets' positions explicitly to create a starting point for a subsequent call to AnimatedLayout.animate(int).

Specified by:

forceLayout in interface AnimatedLayout

See Also:

AnimatedLayout.animate(int), AnimatedLayout.animate(int, Layout.AnimationCallback)

getAnimationDuration

public int getAnimationDuration()

Get the duration of the animated transition between tabs.

Returns:

the duration in milliseconds

getVisibleWidget

public Widget getVisibleWidget()

Gets the currently-visible widget.

Returns:

the visible widget, or null if not visible

getVisibleWidgetIndex

public int getVisibleWidgetIndex()

Gets the index of the currently-visible widget.

Returns:

the visible widget's index

insert

public void insert(IsWidget w,
                   int beforeIndex)

Specified by:

insert in interface InsertPanel.ForIsWidget

insert

public void insert(Widget widget,
                   int beforeIndex)

Description copied from interface: InsertPanel

Inserts a child widget before the specified index. If the widget is already a child of this panel, it will be moved to the specified index.

Specified by:

insert in interface InsertPanel

Parameters:

widget - the child widget to be inserted

beforeIndex - the index before which it will be inserted

insert

public void insert(Widget widget,
                   Widget before)

Insert a widget before the specified widget. If the widget is already a child of this panel, this method behaves as though remove(Widget) had already been called.

Parameters:

widget - the widget to be added

before - the widget before which to insert the new child, or null to append

isAnimationVertical

public boolean isAnimationVertical()

Check whether or not transitions slide in vertically or horizontally. Defaults to horizontally.

Returns:

true for vertical transitions, false for horizontal

onResize

public void onResize()

Description copied from interface: RequiresResize

This method must be called whenever the implementor's size has been modified.

Specified by:

onResize in interface RequiresResize

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

Overrides:

remove in class ComplexPanel

Parameters:

w - the widget to be removed

Returns:

true if the child was present

setAnimationDuration

public void setAnimationDuration(int duration)

Set the duration of the animated transition between tabs.

Parameters:

duration - the duration in milliseconds.

setAnimationVertical

public void setAnimationVertical(boolean isVertical)

Set whether or not transitions slide in vertically or horizontally.

Parameters:

isVertical - true for vertical transitions, false for horizontal

setWidget

public void setWidget(IsWidget w)

Show the specified widget. If the widget is not a child of this panel, it is added to the end of the panel. If the specified widget is null, the currently-visible widget will be hidden.

Specified by:

setWidget in interface AcceptsOneWidget

Parameters:

w - the widget to show, and add if not a child

See Also:

SimplePanel

showWidget

public void showWidget(int index)

Shows the widget at the specified index. This causes the currently- visible widget to be hidden.

Parameters:

index - the index of the widget to be shown

showWidget

public void showWidget(Widget widget)

Shows the widget at the specified index. This causes the currently- visible widget to be hidden.

Parameters:

widget - the widget to be shown

onAttach

protected void onAttach()

Description copied from class: Widget

This method is called when a widget is attached to the browser's document. To receive notification after a Widget has been added to the document, override the Widget.onLoad() method or use Widget.addAttachHandler(com.google.gwt.event.logical.shared.AttachEvent.Handler).

It is strongly recommended that you override Widget.onLoad() or Widget.doAttachChildren() instead of this method to avoid inconsistencies between logical and physical attachment states.

Subclasses that override this method must call super.onAttach() to ensure that the Widget has been attached to its underlying Element.

Overrides:

onAttach in class Widget

See Also:

Widget.onLoad(), Widget.doAttachChildren()

onDetach

protected void onDetach()

Description copied from class: Widget

This method is called when a widget is detached from the browser's document. To receive notification before a Widget is removed from the document, override the Widget.onUnload() method or use Widget.addAttachHandler(com.google.gwt.event.logical.shared.AttachEvent.Handler).

It is strongly recommended that you override Widget.onUnload() or Widget.doDetachChildren() instead of this method to avoid inconsistencies between logical and physical attachment states.

Subclasses that override this method must call super.onDetach() to ensure that the Widget has been detached from the underlying Element. Failure to do so will result in application memory leaks due to circular references between DOM Elements and JavaScript objects.

Overrides:

onDetach in class Widget

See Also:

Widget.onUnload(), Widget.doDetachChildren()

assertIsChild

void assertIsChild(Widget widget)

Assert that the specified widget is null or a child of this widget.

Parameters:

widget - the widget to check