OverlayLayout (Java SE 11 & JDK 11 )
Keywords: javax.swing.OverlayLayout class

Module java.desktop
Package javax.swing

## Class OverlayLayout

- java.lang.Object
- - javax.swing.OverlayLayout

- All Implemented Interfaces:
    `LayoutManager`, `LayoutManager2`, `Serializable`

      public class OverlayLayout
      extends Object
      implements LayoutManager2, Serializable

  A layout manager to arrange components over the top of each other. The requested size of the container will be the largest requested size of the children, taking alignment needs into consideration. The alignment is based upon what is needed to properly fit the children in the allocation area. The children will be placed such that their alignment points are all on top of each other.

  Warning: Serialized objects of this class will not be compatible with future Swing releases. The current serialization support is appropriate for short term storage or RMI between applications running the same version of Swing. As of 1.4, support for long term storage of all JavaBeans™ has been added to the `java.beans` package. Please see `XMLEncoder`.

  Since:
    1.2
  See Also:
    Serialized Form

- - ### Constructor Summary

    Constructors
    Constructor | Description
    --- | ---
    `OverlayLayout​(Container target)` | Constructs a layout manager that performs overlay arrangement of the children.

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method | Description
    --- | --- | ---
    `void` | `addLayoutComponent​(Component comp, Object constraints)` | Adds the specified component to the layout, using the specified constraint object.
    `void` | `addLayoutComponent​(String name, Component comp)` | Adds the specified component to the layout.
    `float` | `getLayoutAlignmentX​(Container target)` | Returns the alignment along the x axis for the container.
    `float` | `getLayoutAlignmentY​(Container target)` | Returns the alignment along the y axis for the container.
    `Container` | `getTarget()` | Returns the container that uses this layout manager.
    `void` | `invalidateLayout​(Container target)` | Indicates a child has changed its layout related information, which causes any cached calculations to be flushed.
    `void` | `layoutContainer​(Container target)` | Called by the AWT when the specified container needs to be laid out.
    `Dimension` | `maximumLayoutSize​(Container target)` | Returns the maximum dimensions needed to lay out the components contained in the specified target container.
    `Dimension` | `minimumLayoutSize​(Container target)` | Returns the minimum dimensions needed to lay out the components contained in the specified target container.
    `Dimension` | `preferredLayoutSize​(Container target)` | Returns the preferred dimensions for this layout given the components in the specified target container.
    `void` | `removeLayoutComponent​(Component comp)` | Removes the specified component from the layout.

    - ### Methods declared in class java.lang.Object

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

- - ### Constructor Detail

    - #### OverlayLayout

          @ConstructorProperties("target")
          public OverlayLayout​(Container target)

      Constructs a layout manager that performs overlay arrangement of the children. The layout manager created is dedicated to the given container.
      Parameters:
        `target` - the container to do layout against

  - ### Method Detail

    - #### getTarget

          public final Container getTarget()

      Returns the container that uses this layout manager.
      Returns:
        the container that uses this layout manager
      Since:
        1.6

    - #### invalidateLayout

          public void invalidateLayout​(Container target)

      Indicates a child has changed its layout related information, which causes any cached calculations to be flushed.
      Specified by:
        `invalidateLayout` in interface `LayoutManager2`
      Parameters:
        `target` - the container

    - #### addLayoutComponent

          public void addLayoutComponent​(String name,
                                         Component comp)

      Adds the specified component to the layout. Used by this class to know when to invalidate layout.
      Specified by:
        `addLayoutComponent` in interface `LayoutManager`
      Parameters:
        `name` - the name of the component
        `comp` - the component to be added

    - #### removeLayoutComponent

          public void removeLayoutComponent​(Component comp)

      Removes the specified component from the layout. Used by this class to know when to invalidate layout.
      Specified by:
        `removeLayoutComponent` in interface `LayoutManager`
      Parameters:
        `comp` - the component to remove

    - #### addLayoutComponent

          public void addLayoutComponent​(Component comp,
                                         Object constraints)

      Adds the specified component to the layout, using the specified constraint object. Used by this class to know when to invalidate layout.
      Specified by:
        `addLayoutComponent` in interface `LayoutManager2`
      Parameters:
        `comp` - the component to be added
        `constraints` - where/how the component is added to the layout.

    - #### preferredLayoutSize

          public Dimension preferredLayoutSize​(Container target)

      Returns the preferred dimensions for this layout given the components in the specified target container. Recomputes the layout if it has been invalidated. Factors in the current inset setting returned by getInsets().
      Specified by:
        `preferredLayoutSize` in interface `LayoutManager`
      Parameters:
        `target` - the component which needs to be laid out
      Returns:
        a Dimension object containing the preferred dimensions
      See Also:
        `minimumLayoutSize(java.awt.Container)`

    - #### minimumLayoutSize

          public Dimension minimumLayoutSize​(Container target)

      Returns the minimum dimensions needed to lay out the components contained in the specified target container. Recomputes the layout if it has been invalidated, and factors in the current inset setting.
      Specified by:
        `minimumLayoutSize` in interface `LayoutManager`
      Parameters:
        `target` - the component which needs to be laid out
      Returns:
        a Dimension object containing the minimum dimensions
      See Also:
        `preferredLayoutSize(java.awt.Container)`

    - #### maximumLayoutSize

          public Dimension maximumLayoutSize​(Container target)

      Returns the maximum dimensions needed to lay out the components contained in the specified target container. Recomputes the layout if it has been invalidated, and factors in the inset setting returned by `getInset`.
      Specified by:
        `maximumLayoutSize` in interface `LayoutManager2`
      Parameters:
        `target` - the component that needs to be laid out
      Returns:
        a `Dimension` object containing the maximum dimensions
      See Also:
        `preferredLayoutSize(java.awt.Container)`

    - #### getLayoutAlignmentX

          public float getLayoutAlignmentX​(Container target)

      Returns the alignment along the x axis for the container.
      Specified by:
        `getLayoutAlignmentX` in interface `LayoutManager2`
      Parameters:
        `target` - the container
      Returns:
        the alignment >= 0.0f && <= 1.0f

    - #### getLayoutAlignmentY

          public float getLayoutAlignmentY​(Container target)

      Returns the alignment along the y axis for the container.
      Specified by:
        `getLayoutAlignmentY` in interface `LayoutManager2`
      Parameters:
        `target` - the container
      Returns:
        the alignment >= 0.0f && <= 1.0f

    - #### layoutContainer

          public void layoutContainer​(Container target)

      Called by the AWT when the specified container needs to be laid out.
      Specified by:
        `layoutContainer` in interface `LayoutManager`
      Parameters:
        `target` - the container to lay out
      Throws:
        `AWTError` - if the target isn't the container specified to the constructor