org.freehep.swing.layout
Class FlowScrollLayout

java.lang.Object
  java.awt.FlowLayout
      org.freehep.swing.layout.FlowScrollLayout

All Implemented Interfaces:

ComponentListener, LayoutManager, LayoutManager2, Serializable, EventListener

public class FlowScrollLayout
extends FlowLayout
implements ComponentListener, LayoutManager2

This class is a replacement for a FlowLayout inside a JScrollPane. It can be used as a plain FlowLayout, but it is intended to be used on a container inside a JScrollPane. If it is the layout for a Container that is the view of a JViewport inside a JScrollPane, then it will cause the Container's children to be wrapped so that the JScrollPane only scrolls vertically.

It can optionally resize all children on each row to be as tall as the tallest one. IMHO, this often looks better, but is off by default for compatiblity with FlowLayout.

Note:Each FlowScrollLayout should be used for only one Container.

Bug:The JViewport inside the JScrollPane that you give to FlowScrollLayout must have a child during the whole time that FlowScrollLayout is used with that JScrollPane. (Typically, that child is the widget whose layout is the FlowScrollLayout.) Otherwise FlowScrollLayout will throw a NullPointerException. It should handle this condition gracefully, but I do not have time to fix it right now. If anyone wants to send me a patch, it would be welcome.

This software is distributed under the Berkeley Software License.

Version:

$Id: FlowScrollLayout.java 8584 2006-08-10 23:06:37Z duns $

Author:

This was written by A. Chris Long (but modified for FreeHEP)

See Also:

Serialized Form

Field Summary

Fields inherited from class java.awt.FlowLayout

CENTER, LEADING, LEFT, RIGHT, TRAILING

Constructor Summary

FlowScrollLayout()

FlowScrollLayout(JScrollPane scrollPane)

FlowScrollLayout(JScrollPane scrollPane, boolean uniformHeight)

Method Summary

void	addLayoutComponent(Component comp, Object constraints) Adds the specified component to the layout, using the specified constraint object.
void	componentHidden(ComponentEvent e)
void	componentMoved(ComponentEvent e)
void	componentResized(ComponentEvent e)
void	componentShown(ComponentEvent e)
protected Dimension	computeDesiredSize() Follow the layout algorithm that FlowLayout uses to compute how big we would like to be, given the size of the containing JScrollPane.
float	getLayoutAlignmentX(Container target) Returns the alignment along the x axis.
float	getLayoutAlignmentY(Container target)
void	invalidateLayout(Container target)
boolean	isUniformHeight()
void	layoutContainer(Container c)
Dimension	maximumLayoutSize(Container target) Returns the maximum size of this component.
static void	setHeights(Container container, int height, int startIndex, int endIndex) Set the preferred size of all JComponents inside container to have height height, starting at the startIndex'th child and going up to endIndex-1.
static void	setPreferredHeight(JComponent comp, int height) Set preferredSize of comp to be Dimension(current preferredSize.width, height)
void	setScrollPane(JScrollPane scrollPane)
void	setUniformHeight(boolean on) If uniformHeight is turned on, all widgets on each row will have their preferred height set to the height of the tallest one (based on preferredSize).
protected void	updateLayout() Update the layout of the managed widget and the containing scrollbar (only if the current size doesn't match the desired size)

Methods inherited from class java.awt.FlowLayout

addLayoutComponent, getAlignment, getHgap, getVgap, minimumLayoutSize, preferredLayoutSize, removeLayoutComponent, setAlignment, setHgap, setVgap, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.awt.LayoutManager

addLayoutComponent, minimumLayoutSize, preferredLayoutSize, removeLayoutComponent

Constructor Detail

FlowScrollLayout

public FlowScrollLayout()

FlowScrollLayout

public FlowScrollLayout(JScrollPane scrollPane)

FlowScrollLayout

public FlowScrollLayout(JScrollPane scrollPane,
                        boolean uniformHeight)

Method Detail

setScrollPane

public void setScrollPane(JScrollPane scrollPane)

setUniformHeight

public void setUniformHeight(boolean on)

If uniformHeight is turned on, all widgets on each row will have their preferred height set to the height of the tallest one (based on preferredSize).

isUniformHeight

public boolean isUniformHeight()

computeDesiredSize

protected Dimension computeDesiredSize()

Follow the layout algorithm that FlowLayout uses to compute how big we would like to be, given the size of the containing JScrollPane. Should not be called unless a non-null JScrollPane has been specified in the constructor or with setScrollPane.

setHeights

public static void setHeights(Container container,
                              int height,
                              int startIndex,
                              int endIndex)

Set the preferred size of all JComponents inside container to have height height, starting at the startIndex'th child and going up to endIndex-1.

setPreferredHeight

public static void setPreferredHeight(JComponent comp,
                                      int height)

Set preferredSize of comp to be Dimension(current preferredSize.width, height)

updateLayout

protected void updateLayout()

Update the layout of the managed widget and the containing scrollbar (only if the current size doesn't match the desired size)

layoutContainer

public void layoutContainer(Container c)

Specified by:

layoutContainer in interface LayoutManager

Overrides:

layoutContainer in class FlowLayout

componentResized

public void componentResized(ComponentEvent e)

Specified by:

componentResized in interface ComponentListener

componentMoved

public void componentMoved(ComponentEvent e)

Specified by:

componentMoved in interface ComponentListener

componentShown

public void componentShown(ComponentEvent e)

Specified by:

componentShown in interface ComponentListener

componentHidden

public void componentHidden(ComponentEvent e)

Specified by:

componentHidden in interface ComponentListener

invalidateLayout

public void invalidateLayout(Container target)

Specified by:

invalidateLayout in interface LayoutManager2

getLayoutAlignmentY

public float getLayoutAlignmentY(Container target)

Specified by:

getLayoutAlignmentY in interface LayoutManager2

getLayoutAlignmentX

public float getLayoutAlignmentX(Container target)

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

maximumLayoutSize

public Dimension maximumLayoutSize(Container target)

Returns the maximum size of this component.

Specified by:

maximumLayoutSize in interface LayoutManager2

See Also:

Component.getMinimumSize(), Component.getPreferredSize(), LayoutManager

addLayoutComponent

public void addLayoutComponent(Component comp,
                               Object constraints)

Adds the specified component to the layout, using the specified constraint object.

Specified by:

addLayoutComponent in interface LayoutManager2

Parameters:

comp - the component to be added

constraints - where/how the component is added to the layout.