com.google.gwt.user.client.ui

## Class StackLayoutPanel

- java.lang.Object
- - com.google.gwt.user.client.ui.UIObject
  - - com.google.gwt.user.client.ui.Widget
    - - com.google.gwt.user.client.ui.Composite
      - - com.google.gwt.user.client.ui.ResizeComposite
        - - com.google.gwt.user.client.ui.StackLayoutPanel

All Implemented Interfaces:
  HasAttachHandlers, HasBeforeSelectionHandlers<java.lang.Integer>, HasSelectionHandlers<java.lang.Integer>, HasHandlers, EventListener, AnimatedLayout, HasVisibility, HasWidgets, IndexedPanel, IndexedPanel.ForIsWidget, IsRenderable, IsWidget, ProvidesResize, RequiresResize, java.lang.Iterable<Widget>

    public class StackLayoutPanel
    extends ResizeComposite
    implements HasWidgets, ProvidesResize, IndexedPanel.ForIsWidget, AnimatedLayout, HasBeforeSelectionHandlers<java.lang.Integer>, HasSelectionHandlers<java.lang.Integer>

A panel that stacks its children vertically, displaying only one at a time, with a header for each child which the user can click to display.

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

### CSS Style Rules

.gwt-StackLayoutPanel
  the panel itself
.gwt-StackLayoutPanel .gwt-StackLayoutPanelHeader
  applied to each header widget
.gwt-StackLayoutPanel .gwt-StackLayoutPanelHeader-hovering
  applied to each header widget on mouse hover
.gwt-StackLayoutPanel .gwt-StackLayoutPanelContent
  applied to each child widget

### Example

>     public class StackLayoutPanelExample implements EntryPoint {

>       public void onModuleLoad() {
>         // Create a three-item stack, with headers sized in EMs.
>         StackLayoutPanel p = new StackLayoutPanel(Unit.EM);
>         p.add(new HTML("this"), new HTML("[this]"), 4);
>         p.add(new HTML("that"), new HTML("[that]"), 4);
>         p.add(new HTML("the other"), new HTML("[the other]"), 4);

>         // Attach the LayoutPanel to the RootLayoutPanel. The latter will listen for
>         // resize events on the window to ensure that its children are informed of
>         // possible size changes.
>         RootLayoutPanel rp = RootLayoutPanel.get();
>         rp.add(p);
>       }
>     }

### Use in UiBinder Templates

A StackLayoutPanel element in a `UiBinder` template may have a `unit` attribute with a `Style.Unit` value (it defaults to PX).

The children of a StackLayoutPanel element are laid out in <g:stack> elements. Each stack can have one widget child and one of two types of header elements. A <g:header> element can hold html, or a <g:customHeader> element can hold a widget. (Note that the tags of the header elements are not capitalized. This is meant to signal that the head is not a runtime object, and so cannot have a `ui:field` attribute.)

For example:

     <g:StackLayoutPanel unit='PX'>
      <g:stack>
        <g:header size='3'><b>HTML</b> header</g:header>
        <g:Label>able</g:Label>
      </g:stack>
      <g:stack>
        <g:customHeader size='3'>
          <g:Label>Custom header</g:Label>
        </g:customHeader>
        <g:Label>baker</g:Label>
      </g:stack>
     </g:StackLayoutPanel>

### Nested Class Summary

### Nested classes/interfaces inherited from class com.google.gwt.user.client.ui.UIObject

`UIObject.DebugIdImpl, UIObject.DebugIdImplEnabled`

### Nested classes/interfaces inherited from interface com.google.gwt.user.client.ui.HasWidgets

`HasWidgets.ForIsWidget`

### Field Summary

### Fields inherited from class com.google.gwt.user.client.ui.Widget

`eventsToSink`

### Fields inherited from class com.google.gwt.user.client.ui.UIObject

`DEBUG_ID_PREFIX, MISSING_ELEMENT_ERROR, SETELEMENT_TWICE_ERROR`

### Constructor Summary

Constructors
Constructor and Description
`StackLayoutPanel(Style.Unit unit)` Creates an empty stack panel.

### Method Summary

All Methods Instance Methods Concrete Methods
`void` `add(IsWidget widget, IsWidget header, double headerSize)` Overloaded version for IsWidget.
`void` `add(IsWidget widget, java.lang.String header, boolean asHtml, double headerSize)` Overloaded version for IsWidget.
`void` `add(Widget w)` Adds a child widget.
`void` `add(Widget widget, SafeHtml header, double headerSize)` Adds a child widget to this stack, along with a widget representing the stack header.
`void` `add(Widget widget, java.lang.String header, boolean asHtml, double headerSize)` Adds a child widget to this stack, along with a widget representing the stack header.
`void` `add(Widget widget, java.lang.String header, double headerSize)` Adds a child widget to this stack, along with a widget representing the stack header.
`void` `add(Widget widget, Widget header, double headerSize)` Adds a child widget to this stack, along with a widget representing the stack header.
`HandlerRegistration` `addBeforeSelectionHandler(BeforeSelectionHandler<java.lang.Integer> handler)` Adds a `BeforeSelectionEvent` handler.
`HandlerRegistration` `addSelectionHandler(SelectionHandler<java.lang.Integer> handler)` Adds a `SelectionEvent` handler.
`void` `animate(int duration)` Layout children, animating over the specified period of time.
`void` `animate(int duration, Layout.AnimationCallback callback)` Layout children, animating over the specified period of time.
`void` `clear()` Removes all child widgets.
`void` `forceLayout()` Layout children immediately.
`int` `getAnimationDuration()` Get the duration of the animated transition between children.
`Widget` `getHeaderWidget(int index)` Gets the widget in the stack header at the given index.
`Widget` `getHeaderWidget(Widget child)` Gets the widget in the stack header associated with the given child widget.
`int` `getVisibleIndex()` Gets the currently-selected index.
`Widget` `getVisibleWidget()` Gets the currently-selected widget.
`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(IsWidget child)`
`int` `getWidgetIndex(Widget child)` Gets the index of the specified child widget.
`void` `insert(Widget child, SafeHtml html, double headerSize, int beforeIndex)` Inserts a widget into the panel.
`void` `insert(Widget child, java.lang.String text, boolean asHtml, double headerSize, int beforeIndex)` Inserts a widget into the panel.
`void` `insert(Widget child, java.lang.String text, double headerSize, int beforeIndex)` Inserts a widget into the panel.
`void` `insert(Widget child, Widget header, double headerSize, int beforeIndex)` Inserts a widget into the panel.
`java.util.Iterator<Widget>` `iterator()` Gets an iterator for the contained widgets.
`protected void` `onLoad()` This method is called immediately after a widget becomes attached to the browser's document.
`void` `onResize()` This method must be called whenever the implementor's size has been modified.
`boolean` `remove(int index)` Removes the widget at the specified index.
`boolean` `remove(Widget child)` Removes a child widget.
`void` `setAnimationDuration(int duration)` Set the duration of the animated transition between children.
`void` `setHeaderHTML(int index, SafeHtml html)` Sets a stack header's HTML contents.
`void` `setHeaderHTML(int index, java.lang.String html)` Sets a stack header's HTML contents.
`void` `setHeaderText(int index, java.lang.String text)` Sets a stack header's text contents.
`void` `showWidget(int index)` Shows the widget at the specified index and fires events.
`void` `showWidget(int index, boolean fireEvents)` Shows the widget at the specified index.
`void` `showWidget(Widget child)` Shows the specified widget and fires events.
`void` `showWidget(Widget child, boolean fireEvents)` Shows the specified widget.

### Methods inherited from class com.google.gwt.user.client.ui.ResizeComposite

`initWidget`

### Methods inherited from class com.google.gwt.user.client.ui.Composite

`claimElement, getWidget, initializeClaimedElement, isAttached, onAttach, onBrowserEvent, onDetach, render, render, resolvePotentialElement, setWidget`

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

`addAttachHandler, addBitlessDomHandler, addDomHandler, addHandler, asWidget, asWidgetOrNull, createHandlerManager, delegateEvent, doAttachChildren, doDetachChildren, ensureHandlers, fireEvent, getHandlerCount, getHandlerManager, getLayoutData, getParent, isOrWasAttached, onUnload, removeFromParent, replaceElement, setLayoutData, setParent, sinkEvents, unsinkEvents`

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

`addStyleDependentName, addStyleName, ensureDebugId, ensureDebugId, ensureDebugId, getAbsoluteLeft, getAbsoluteTop, getElement, getOffsetHeight, getOffsetWidth, getStyleElement, getStyleName, getStyleName, getStylePrimaryName, getStylePrimaryName, getTitle, isVisible, isVisible, onEnsureDebugId, removeStyleDependentName, removeStyleName, setElement, setElement, setHeight, setPixelSize, setSize, setStyleDependentName, setStyleName, setStyleName, setStyleName, setStyleName, setStylePrimaryName, setStylePrimaryName, setTitle, setVisible, setVisible, setWidth, sinkBitlessEvent, toString`

### Methods inherited from class java.lang.Object

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

### Methods inherited from interface java.lang.Iterable

`forEach, spliterator`

### Methods inherited from interface com.google.gwt.event.shared.HasHandlers

`fireEvent`

### Constructor Detail

#### StackLayoutPanel

    public StackLayoutPanel(Style.Unit unit)

Creates an empty stack panel.

Parameters:
  `unit` - the unit to be used for layout

### Method Detail

#### add

    public void add(Widget w)

Description copied from interface: `HasWidgets`
Adds a child widget.

Specified by:
  `add` in interface `HasWidgets`
Parameters:
  `w` - the widget to be added

#### add

    public void add(Widget widget,
                    SafeHtml header,
                    double headerSize)

Adds a child widget to this stack, along with a widget representing the stack header.

Parameters:
  `widget` - the child widget to be added
  `header` - the html to be shown on its header
  `headerSize` - the size of the header widget

#### add

    public void add(Widget widget,
                    java.lang.String header,
                    boolean asHtml,
                    double headerSize)

Adds a child widget to this stack, along with a widget representing the stack header.

Parameters:
  `widget` - the child widget to be added
  `header` - the text to be shown on its header
  `asHtml` - `true` to treat the specified text as HTML
  `headerSize` - the size of the header widget

#### add

    public void add(IsWidget widget,
                    java.lang.String header,
                    boolean asHtml,
                    double headerSize)

Overloaded version for IsWidget.

See Also:
  `add(Widget,String,boolean,double)`

#### add

    public void add(Widget widget,
                    java.lang.String header,
                    double headerSize)

Adds a child widget to this stack, along with a widget representing the stack header.

Parameters:
  `widget` - the child widget to be added
  `header` - the text to be shown on its header
  `headerSize` - the size of the header widget

#### add

    public void add(Widget widget,
                    Widget header,
                    double headerSize)

Adds a child widget to this stack, along with a widget representing the stack header.

Parameters:
  `widget` - the child widget to be added
  `header` - the header widget
  `headerSize` - the size of the header widget

#### add

    public void add(IsWidget widget,
                    IsWidget header,
                    double headerSize)

Overloaded version for IsWidget.

See Also:
  `add(Widget,Widget,double)`

#### addBeforeSelectionHandler

    public HandlerRegistration addBeforeSelectionHandler(BeforeSelectionHandler<java.lang.Integer> handler)

Description copied from interface: `HasBeforeSelectionHandlers`
Adds a `BeforeSelectionEvent` handler.

Specified by:
  `addBeforeSelectionHandler` in interface `HasBeforeSelectionHandlers<java.lang.Integer>`
Parameters:
  `handler` - the handler
Returns:
  the registration for the event

#### addSelectionHandler

    public HandlerRegistration addSelectionHandler(SelectionHandler<java.lang.Integer> handler)

Description copied from interface: `HasSelectionHandlers`
Adds a `SelectionEvent` handler.

Specified by:
  `addSelectionHandler` in interface `HasSelectionHandlers<java.lang.Integer>`
Parameters:
  `handler` - the handler
Returns:
  the registration for the event

#### 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

#### clear

    public void clear()

Description copied from interface: `HasWidgets`
Removes all child widgets.

Specified by:
  `clear` in interface `HasWidgets`

#### 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 children.

Returns:
  the duration in milliseconds

#### getHeaderWidget

    public Widget getHeaderWidget(int index)

Gets the widget in the stack header at the given index.

Parameters:
  `index` - the index of the stack header to be retrieved
Returns:
  the header widget

#### getHeaderWidget

    public Widget getHeaderWidget(Widget child)

Gets the widget in the stack header associated with the given child widget.

Parameters:
  `child` - the child whose stack header is to be retrieved
Returns:
  the header widget

#### getVisibleIndex

    public int getVisibleIndex()

Gets the currently-selected index.

Returns:
  the selected index, or `-1` if none is selected

#### getVisibleWidget

    public Widget getVisibleWidget()

Gets the currently-selected widget.

Returns:
  the selected widget, or `null` if none exist

#### 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(IsWidget child)

Specified by:
  `getWidgetIndex` in interface `IndexedPanel.ForIsWidget`

#### 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

#### insert

    public void insert(Widget child,
                       SafeHtml html,
                       double headerSize,
                       int beforeIndex)

Inserts a widget into the panel. If the Widget is already attached, it will be moved to the requested index.

Parameters:
  `child` - the widget to be added
  `html` - the safe html to be shown on its header
  `headerSize` - the size of the header widget
  `beforeIndex` - the index before which it will be inserted

#### insert

    public void insert(Widget child,
                       java.lang.String text,
                       boolean asHtml,
                       double headerSize,
                       int beforeIndex)

Inserts a widget into the panel. If the Widget is already attached, it will be moved to the requested index.

Parameters:
  `child` - the widget to be added
  `text` - the text to be shown on its header
  `asHtml` - `true` to treat the specified text as HTML
  `headerSize` - the size of the header widget
  `beforeIndex` - the index before which it will be inserted

#### insert

    public void insert(Widget child,
                       java.lang.String text,
                       double headerSize,
                       int beforeIndex)

Inserts a widget into the panel. If the Widget is already attached, it will be moved to the requested index.

Parameters:
  `child` - the widget to be added
  `text` - the text to be shown on its header
  `headerSize` - the size of the header widget
  `beforeIndex` - the index before which it will be inserted

#### insert

    public void insert(Widget child,
                       Widget header,
                       double headerSize,
                       int beforeIndex)

Inserts a widget into the panel. If the Widget is already attached, it will be moved to the requested index.

Parameters:
  `child` - the widget to be added
  `header` - the widget to be placed in the associated header
  `headerSize` - the size of the header widget
  `beforeIndex` - the index before which it will be inserted

#### iterator

    public java.util.Iterator<Widget> 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`
Specified by:
  `iterator` in interface `java.lang.Iterable<Widget>`

#### 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`
Overrides:
  `onResize` in class `ResizeComposite`

#### 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 child)

Description copied from interface: `HasWidgets`
Removes a child widget.

Specified by:
  `remove` in interface `HasWidgets`
Parameters:
  `child` - the widget to be removed
Returns:
  `true` if the widget was present

#### setAnimationDuration

    public void setAnimationDuration(int duration)

Set the duration of the animated transition between children.

Parameters:
  `duration` - the duration in milliseconds.

#### setHeaderHTML

    public void setHeaderHTML(int index,
                              java.lang.String html)

Sets a stack header's HTML contents. Use care when setting an object's HTML; it is an easy way to expose script-based security problems. Consider using `setHeaderHTML(int, SafeHtml)` or `setHeaderText(int, String)` whenever possible.

Parameters:
  `index` - the index of the header whose HTML is to be set
  `html` - the header's new HTML contents

#### setHeaderHTML

    public void setHeaderHTML(int index,
                              SafeHtml html)

Sets a stack header's HTML contents.

Parameters:
  `index` - the index of the header whose HTML is to be set
  `html` - the header's new HTML contents

#### setHeaderText

    public void setHeaderText(int index,
                              java.lang.String text)

Sets a stack header's text contents.

Parameters:
  `index` - the index of the header whose text is to be set
  `text` - the object's new text

#### showWidget

    public void showWidget(int index)

Shows the widget at the specified index and fires events.

Parameters:
  `index` - the index of the child widget to be shown.

#### showWidget

    public void showWidget(int index,
                           boolean fireEvents)

Shows the widget at the specified index.

Parameters:
  `index` - the index of the child widget to be shown.
  `fireEvents` - true to fire events, false not to

#### showWidget

    public void showWidget(Widget child)

Shows the specified widget and fires events.

Parameters:
  `child` - the child widget to be shown.

#### showWidget

    public void showWidget(Widget child,
                           boolean fireEvents)

Shows the specified widget.

Parameters:
  `child` - the child widget to be shown.
  `fireEvents` - true to fire events, false not to

#### onLoad

    protected void onLoad()

Description copied from class: `Widget`
This method is called immediately after a widget becomes attached to the browser's document.

Overrides:
  `onLoad` in class `Widget`