com.google.gwt.user.client.ui

## Class StackPanel

- 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.StackPanel

- All Implemented Interfaces:
    HasAttachHandlers, HasHandlers, EventListener, HasVisibility, HasWidgets, HasWidgets.ForIsWidget, IndexedPanel, IndexedPanel.ForIsWidget, InsertPanel, InsertPanel.ForIsWidget, IsWidget, java.lang.Iterable<Widget>
  Direct Known Subclasses:
    DecoratedStackPanel

      public class StackPanel
      extends ComplexPanel
      implements InsertPanel.ForIsWidget

  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 quirks mode. If your application is in Standards Mode, use `StackLayoutPanel` instead.

  ### CSS Style Rules

  - .gwt-StackPanel { the panel itself }
  - .gwt-StackPanel .gwt-StackPanelItem { unselected items }
  - .gwt-StackPanel .gwt-StackPanelItem-selected { selected items }
  - .gwt-StackPanel .gwt-StackPanelContent { the wrapper around the contents of the item }

  ### Example

  >     public class StackPanelExample implements EntryPoint {

  >       public void onModuleLoad() {
  >         // Create a stack panel containing three labels.
  >         StackPanel panel = new StackPanel();
  >         panel.add(new Label("Foo"), "foo");
  >         panel.add(new Label("Bar"), "bar");
  >         panel.add(new Label("Baz"), "baz");

  >         // Add it to the root panel.
  >         RootPanel.get().add(panel);
  >       }
  >     }

  See Also:
    `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.InsertPanel

      `InsertPanel.ForIsWidget`

    - ### 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
    `StackPanel()` Creates an empty stack panel.

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `add(Widget w)` Adds a child widget.
    `void` | `add(Widget w, SafeHtml stackHtml)` Adds a new child with the given widget and header, optionally interpreting the header as HTML.
    `void` | `add(Widget w, java.lang.String stackText)` Adds a new child with the given widget and header.
    `void` | `add(Widget w, java.lang.String stackText, boolean asHTML)` Adds a new child with the given widget and header, optionally interpreting the header as HTML.
    `(package private) Element` | `createHeaderElem()` Returns a header element.
    `(package private) Element` | `getHeaderTextElem(Element headerElem)` Get the element that holds the header text given the header element created by #createHeaderElement.
    `int` | `getSelectedIndex()` Gets the currently selected child index.
    `void` | `insert(IsWidget w, int beforeIndex)`
    `void` | `insert(Widget w, int beforeIndex)` Inserts a child widget before the specified index.
    `void` | `onBrowserEvent(Event event)` Fired whenever a browser event is received.
    `protected void` | `onEnsureDebugId(java.lang.String baseID)` Affected Elements: -text# = The element around the header at the specified index. -text-wrapper# = The element around the header at the specified index. -content# = The element around the body at the specified index.
    `boolean` | `remove(int index)` Removes the widget at the specified index.
    `boolean` | `remove(Widget child)` Removes a child widget.
    `void` | `setStackText(int index, SafeHtml html)` Sets the html associated with a child by its index.
    `void` | `setStackText(int index, java.lang.String text)` Sets the text associated with a child by its index.
    `void` | `setStackText(int index, java.lang.String text, boolean asHTML)` Sets the text associated with a child by its index.
    `void` | `showStack(int index)` Shows the widget at the specified child index.

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

      `add, adjustIndex, checkIndexBoundsForAccess, checkIndexBoundsForInsertion, doLogicalClear, getChildren, getWidget, getWidgetCount, getWidgetIndex, getWidgetIndex, insert, insert, iterator`

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

      `add, adopt, adopt, clear, disown, doAttachChildren, doDetachChildren, orphan, remove`

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

      `addAttachHandler, addBitlessDomHandler, addDomHandler, addHandler, asWidget, asWidgetOrNull, createHandlerManager, delegateEvent, ensureHandlers, fireEvent, getHandlerCount, getHandlerManager, getLayoutData, getParent, isAttached, isOrWasAttached, onAttach, onDetach, onLoad, onUnload, removeFromParent, replaceElement, setLayoutData, setParent, sinkEvents`

    - ### 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, removeStyleDependentName, removeStyleName, resolvePotentialElement, setElement, setElement, setHeight, setPixelSize, setSize, setStyleDependentName, setStyleName, setStyleName, setStyleName, setStyleName, setStylePrimaryName, setStylePrimaryName, setTitle, setVisible, setVisible, setWidth, sinkBitlessEvent, toString, unsinkEvents`

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

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

    - ### Methods inherited from interface com.google.gwt.user.client.ui.InsertPanel.ForIsWidget

      `add`

    - ### Methods inherited from interface com.google.gwt.user.client.ui.IndexedPanel.ForIsWidget

      `getWidgetIndex`

    - ### Methods inherited from interface com.google.gwt.user.client.ui.IndexedPanel

      `getWidget, getWidgetCount, getWidgetIndex`

- - ### Constructor Detail

    - #### StackPanel

          public StackPanel()

      Creates an empty stack panel.

  - ### Method Detail

    - #### 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)`

    - #### add

          public void add(Widget w,
                 java.lang.String stackText)

      Adds a new child with the given widget and header.
      Parameters:
        `w` - the widget to be added
        `stackText` - the header text associated with this widget

    - #### add

          public void add(Widget w,
                 SafeHtml stackHtml)

      Adds a new child with the given widget and header, optionally interpreting the header as HTML.
      Parameters:
        `w` - the widget to be added
        `stackHtml` - the header html associated with this widget

    - #### add

          public void add(Widget w,
                 java.lang.String stackText,
                 boolean asHTML)

      Adds a new child with the given widget and header, optionally interpreting the header as HTML.
      Parameters:
        `w` - the widget to be added
        `stackText` - the header text associated with this widget
        `asHTML` - `true` to treat the specified text as HTML

    - #### getSelectedIndex

          public int getSelectedIndex()

      Gets the currently selected child index.
      Returns:
        selected child

    - #### insert

          public void insert(IsWidget w,
                    int beforeIndex)

      Specified by:
        `insert` in interface `InsertPanel.ForIsWidget`

    - #### insert

          public void insert(Widget w,
                    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:
        `w` - the child widget to be inserted
        `beforeIndex` - the index before which it will be inserted

    - #### onBrowserEvent

          public void onBrowserEvent(Event event)

      Description copied from interface: `EventListener`
      Fired whenever a browser event is received.
      Specified by:
        `onBrowserEvent` in interface `EventListener`
      Overrides:
        `onBrowserEvent` in class `Widget`
      Parameters:
        `event` - the event received

    - #### remove

          public boolean remove(int index)

      Description copied from interface: `IndexedPanel`
      Removes the widget at the specified index.
      Specified by:
        `remove` in interface `IndexedPanel`
      Overrides:
        `remove` in class `ComplexPanel`
      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 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:
        `child` - the widget to be removed
      Returns:
        `true` if the child was present

    - #### setStackText

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

      Sets the text associated with a child by its index.
      Parameters:
        `index` - the index of the child whose text is to be set
        `text` - the text to be associated with it

    - #### setStackText

          public void setStackText(int index,
                          SafeHtml html)

      Sets the html associated with a child by its index.
      Parameters:
        `index` - the index of the child whose text is to be set
        `html` - the html to be associated with it

    - #### setStackText

          public void setStackText(int index,
                          java.lang.String text,
                          boolean asHTML)

      Sets the text associated with a child by its index.
      Parameters:
        `index` - the index of the child whose text is to be set
        `text` - the text to be associated with it
        `asHTML` - `true` to treat the specified text as HTML

    - #### showStack

          public void showStack(int index)

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

    - #### onEnsureDebugId

          protected void onEnsureDebugId(java.lang.String baseID)

      Affected Elements:
      - -text# = The element around the header at the specified index.
      - -text-wrapper# = The element around the header at the specified index.
      - -content# = The element around the body at the specified index.
      Overrides:
        `onEnsureDebugId` in class `UIObject`
      Parameters:
        `baseID` - the base ID used by the main element
      See Also:
        `UIObject.onEnsureDebugId(String)`

    - #### createHeaderElem

          Element createHeaderElem()

      Returns a header element.

    - #### getHeaderTextElem

          Element getHeaderTextElem(Element headerElem)

      Get the element that holds the header text given the header element created by #createHeaderElement.
      Parameters:
        `headerElem` - the header element
      Returns:
        the element around the header text