CardLayout (Java SE 26 & JDK 26)
Description: declaration: module: java.desktop, package: java.awt, class: CardLayout
Keywords: java.awt.CardLayout class

# Class CardLayout

java.lang.Object
java.awt.CardLayout

All Implemented Interfaces:
  `LayoutManager, LayoutManager2, Serializable`

public class CardLayout extends Object implements LayoutManager2, Serializable
A `CardLayout` object is a layout manager for a container. It treats each component in the container as a card. Only one card is visible at a time, and the container acts as a stack of cards. The first component added to a `CardLayout` object is the visible component when the container is first displayed.

The ordering of cards is determined by the container's own internal ordering of its component objects. `CardLayout` defines a set of methods that allow an application to flip through these cards sequentially, or to show a specified card. The `addLayoutComponent(Component, Object)` method can be used to associate a string identifier with a given card for fast random access.

Since:
  1.0
See Also:
  - `Container`
  - Serialized Form

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `CardLayout()`
  Creates a new card layout with gaps of size zero.
  `CardLayout(int hgap, int vgap)`
  Creates a new card layout with the specified horizontal and vertical gaps.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `void`
  `addLayoutComponent(Component comp, Object constraints)`
  Adds the specified component to this card layout's internal table of names.
  `void`
  `addLayoutComponent(String name, Component comp)`
  Deprecated.
  replaced by `addLayoutComponent(Component, Object)`.
  `void`
  `first(Container parent)`
  Flips to the first card of the container.
  `int`
  `getHgap()`
  Gets the horizontal gap between components.
  `float`
  `getLayoutAlignmentX(Container parent)`
  Returns the alignment along the x axis.
  `float`
  `getLayoutAlignmentY(Container parent)`
  Returns the alignment along the y axis.
  `int`
  `getVgap()`
  Gets the vertical gap between components.
  `void`
  `invalidateLayout(Container target)`
  Invalidates the layout, indicating that if the layout manager has cached information it should be discarded.
  `void`
  `last(Container parent)`
  Flips to the last card of the container.
  `void`
  `layoutContainer(Container parent)`
  Lays out the specified container using this card layout.
  `Dimension`
  `maximumLayoutSize(Container target)`
  Returns the maximum dimensions for this layout given the components in the specified target container.
  `Dimension`
  `minimumLayoutSize(Container parent)`
  Calculates the minimum size for the specified panel.
  `void`
  `next(Container parent)`
  Flips to the next card of the specified container.
  `Dimension`
  `preferredLayoutSize(Container parent)`
  Determines the preferred size of the container argument using this card layout.
  `void`
  `previous(Container parent)`
  Flips to the previous card of the specified container.
  `void`
  `removeLayoutComponent(Component comp)`
  Removes the specified component from the layout.
  `void`
  `setHgap(int hgap)`
  Sets the horizontal gap between components.
  `void`
  `setVgap(int vgap)`
  Sets the vertical gap between components.
  `void`
  `show(Container parent, String name)`
  Flips to the component that was added to this layout with the specified `name`, using `addLayoutComponent`.
  `String`
  `toString()`
  Returns a string representation of the state of this card layout.

  ### Methods declared in class Object

  `clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait`
  Modifier and Type
  Method
  Description
  `protected Object`
  `clone()`
  Creates and returns a copy of this object.
  `boolean`
  `equals(Object obj)`
  Indicates whether some other object is "equal to" this one.
  `protected void`
  `finalize()`
  Deprecated, for removal: This API element is subject to removal in a future version.
  Finalization is deprecated and subject to removal in a future release.
  `final Class<?>`
  `getClass()`
  Returns the runtime class of this `Object`.
  `int`
  `hashCode()`
  Returns a hash code value for this object.
  `final void`
  `notify()`
  Wakes up a single thread that is waiting on this object's monitor.
  `final void`
  `notifyAll()`
  Wakes up all threads that are waiting on this object's monitor.
  `final void`
  `wait()`
  Causes the current thread to wait until it is awakened, typically by being notified or interrupted.
  `final void`
  `wait(long timeoutMillis)`
  Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
  `final void`
  `wait(long timeoutMillis, int nanos)`
  Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.

- ## Constructor Details

  - ### CardLayout

    public CardLayout()
    Creates a new card layout with gaps of size zero.

  - ### CardLayout

    public CardLayout(int hgap, int vgap)
    Creates a new card layout with the specified horizontal and vertical gaps. The horizontal gaps are placed at the left and right edges. The vertical gaps are placed at the top and bottom edges.
    Parameters:
      `hgap` - the horizontal gap.
      `vgap` - the vertical gap.

- ## Method Details

  - ### getHgap

    public int getHgap()
    Gets the horizontal gap between components.
    Returns:
      the horizontal gap between components.
    Since:
      1.1
    See Also:
      - `setHgap(int)`
      - `getVgap()`

  - ### setHgap

    public void setHgap(int hgap)
    Sets the horizontal gap between components.
    Parameters:
      `hgap` - the horizontal gap between components.
    Since:
      1.1
    See Also:
      - `getHgap()`
      - `setVgap(int)`

  - ### getVgap

    public int getVgap()
    Gets the vertical gap between components.
    Returns:
      the vertical gap between components.
    See Also:
      - `setVgap(int)`
      - `getHgap()`

  - ### setVgap

    public void setVgap(int vgap)
    Sets the vertical gap between components.
    Parameters:
      `vgap` - the vertical gap between components.
    Since:
      1.1
    See Also:
      - `getVgap()`
      - `setHgap(int)`

  - ### addLayoutComponent

    public void addLayoutComponent(Component comp, Object constraints)
    Adds the specified component to this card layout's internal table of names. The object specified by `constraints` must be a string. The card layout stores this string as a key-value pair that can be used for random access to a particular card. By calling the `show` method, an application can display the component with the specified name.
    Specified by:
      `addLayoutComponent` in interface `LayoutManager2`
    Parameters:
      `comp` - the component to be added.
      `constraints` - a tag that identifies a particular card in the layout.
    Throws:
      `IllegalArgumentException` - if the constraint is not a string.
    See Also:
      - `show(java.awt.Container, java.lang.String)`

  - ### addLayoutComponent

    @Deprecated public void addLayoutComponent(String name, Component comp)
    Deprecated.
    replaced by `addLayoutComponent(Component, Object)`.
    Description copied from interface: `LayoutManager`
    If the layout manager uses a per-component string, adds the component `comp` to the layout, associating it with the string specified by `name`.
    Specified by:
      `addLayoutComponent` in interface `LayoutManager`
    Parameters:
      `name` - the string to be associated with the component
      `comp` - the component to be added

  - ### removeLayoutComponent

    public void removeLayoutComponent(Component comp)
    Removes the specified component from the layout. If the card was visible on top, the next card underneath it is shown.
    Specified by:
      `removeLayoutComponent` in interface `LayoutManager`
    Parameters:
      `comp` - the component to be removed.
    See Also:
      - `Container.remove(java.awt.Component)`
      - `Container.removeAll()`

  - ### preferredLayoutSize

    public Dimension preferredLayoutSize(Container parent)
    Determines the preferred size of the container argument using this card layout.
    Specified by:
      `preferredLayoutSize` in interface `LayoutManager`
    Parameters:
      `parent` - the parent container in which to do the layout
    Returns:
      the preferred dimensions to lay out the subcomponents of the specified container
    See Also:
      - `Container.getPreferredSize()`
      - `minimumLayoutSize(Container)`

  - ### minimumLayoutSize

    public Dimension minimumLayoutSize(Container parent)
    Calculates the minimum size for the specified panel.
    Specified by:
      `minimumLayoutSize` in interface `LayoutManager`
    Parameters:
      `parent` - the parent container in which to do the layout
    Returns:
      the minimum dimensions required to lay out the subcomponents of the specified container
    See Also:
      - `Container.doLayout()`
      - `preferredLayoutSize(Container)`

  - ### maximumLayoutSize

    public Dimension maximumLayoutSize(Container target)
    Returns the maximum dimensions for this layout given the components in the specified target container.
    Specified by:
      `maximumLayoutSize` in interface `LayoutManager2`
    Parameters:
      `target` - the component which needs to be laid out
    Returns:
      the maximum size of the container
    See Also:
      - `Container`
      - `minimumLayoutSize(Container)`
      - `preferredLayoutSize(Container)`

  - ### getLayoutAlignmentX

    public float getLayoutAlignmentX(Container parent)
    Returns the alignment along the x axis. This specifies how the component would like to be aligned relative to other components. The value should be a number between 0 and 1 where 0 represents alignment along the origin, 1 is aligned the furthest away from the origin, 0.5 is centered, etc.
    Specified by:
      `getLayoutAlignmentX` in interface `LayoutManager2`
    Parameters:
      `parent` - the target container
    Returns:
      the x-axis alignment preference

  - ### getLayoutAlignmentY

    public float getLayoutAlignmentY(Container parent)
    Returns the alignment along the y axis. This specifies how the component would like to be aligned relative to other components. The value should be a number between 0 and 1 where 0 represents alignment along the origin, 1 is aligned the furthest away from the origin, 0.5 is centered, etc.
    Specified by:
      `getLayoutAlignmentY` in interface `LayoutManager2`
    Parameters:
      `parent` - the target container
    Returns:
      the y-axis alignment preference

  - ### invalidateLayout

    public void invalidateLayout(Container target)
    Invalidates the layout, indicating that if the layout manager has cached information it should be discarded.
    Specified by:
      `invalidateLayout` in interface `LayoutManager2`
    Parameters:
      `target` - the target container

  - ### layoutContainer

    public void layoutContainer(Container parent)
    Lays out the specified container using this card layout.

    Each component in the `parent` container is reshaped to be the size of the container, minus space for surrounding insets, horizontal gaps, and vertical gaps.

    Specified by:
      `layoutContainer` in interface `LayoutManager`
    Parameters:
      `parent` - the parent container in which to do the layout
    See Also:
      - `Container.doLayout()`

  - ### first

    public void first(Container parent)
    Flips to the first card of the container.
    Parameters:
      `parent` - the parent container in which to do the layout
    See Also:
      - `last(Container)`

  - ### next

    public void next(Container parent)
    Flips to the next card of the specified container. If the currently visible card is the last one, this method flips to the first card in the layout.
    Parameters:
      `parent` - the parent container in which to do the layout
    See Also:
      - `previous(Container)`

  - ### previous

    public void previous(Container parent)
    Flips to the previous card of the specified container. If the currently visible card is the first one, this method flips to the last card in the layout.
    Parameters:
      `parent` - the parent container in which to do the layout
    See Also:
      - `next(Container)`

  - ### last

    public void last(Container parent)
    Flips to the last card of the container.
    Parameters:
      `parent` - the parent container in which to do the layout
    See Also:
      - `first(Container)`

  - ### show

    public void show(Container parent, String name)
    Flips to the component that was added to this layout with the specified `name`, using `addLayoutComponent`. If no such component exists, then nothing happens.
    Parameters:
      `parent` - the parent container in which to do the layout
      `name` - the component name
    See Also:
      - `addLayoutComponent(java.awt.Component, java.lang.Object)`

  - ### toString

    public String toString()
    Returns a string representation of the state of this card layout.
    Overrides:
      `toString` in class `Object`
    Returns:
      a string representation of this card layout.