jApp
Class BetterBoxLayout

java.lang.Object
  jApp.BetterBoxLayout

All Implemented Interfaces:

java.awt.LayoutManager

public class BetterBoxLayout
extends java.lang.Object
implements java.awt.LayoutManager

Implements a layout quite similar to javax.swing.BoxLayout, only better.

BetterBoxLay out can be used to lay out components in row or a column. In the following description horizontal (row) orientation is assumend. To understand how the vertical orientation works, just re-read the description and replace/swap column for row, width for height, horizontal for vertical etc. The following constants are used to set the orientation of the layout. These and other constants need to be combined and passed to the constructor to define the layout behaviour.

X_AXIS

Y_AXIS

In the horizontal direction components are laid out in a row, one after another. Glue objects, struts and rigid areas can be inserted, just like with a regular BoxLayout.

Here is a short description of glue, struts and rigid areas, all of which are invisible objects:

a glue objects is a zero sized component that will stretch if space is available.

a strut is like a one dimensional spacer, it will occupy space but in one direction only

a rigid area is a two dimensional spacer, and like a strut it will not stretch or shrink

Horizontal Component Placement / Width

The components minimum and maximums sizes are always observed.

If there are no glue objects then the components are resized in the horizontal direction as needed to fill the space available, (within the components minimum and maximum widths). When resising the components the relative widths of components (as defined by their preferred widths) are maintained as far as possible.

If there are glue objects and there is extra in the horizontal direction then the extra space is used to expand those glue objects evenly to fill the available space.

If there are no glue objects and the components cannot be stretched to fill the space available, then the extra space is added to the beginning and enf of the row.

Component Height

The components minimum and maximums sizes are always observed.

Each components height is determined by its minimum, maximum, preferred or container's height depending on the passed to the constructor of layout manager:

MINIMUM_HEIGHT - each component will obey its minimum height

PREFERRED_HEIGHT- each component will obey its preferred height

MAXIMUM_HEIGHT - each component will obey its maximum height

CONTAINER_HEIGHT - each component will obey the containers height

In addtion to those the following flag can be used to ensure that no component will be higher than it's container.

CLIPPED_HEIGHT

Vertical Component Placement

In the vertical direction all components on the same line. If there is extra space in the vertical direction then the components Y-aligment value is used to determine where (vertically) in the available space the the component is placed. An allignment value of 0.0F will align the top of the component with the top of the container and a value of 1.0F will allign the bottom with bottom (if possible).

A major difference from javax.swing.BoxLayout is that BetterBoxLayout does NOT ignore invisible components (by default). If hidden components are NOT ignored then hiding a component does NOT affect the layout. This is usually better behaviour because otherwise the remaining (visible) buttons would move, which is (usually) poor UI practice. Disabling buttons is of course often an option but there are many situation in which the preferred choise is hiding.

The following constant can be used tell the layout manager to ignore hidden (invisible) components.

IGNORE_HIDDEN

Copyright: Copyright (c) 2004 Kusta Nyholm Oy

Version:

1.0

Author:

Kustaa Nyholm

Field Summary

static int	CLIPPED_HEIGHT Limit component height to container height
static int	CLIPPED_WIDTH Limit component width to container width
static int	CONTAINER_HEIGHT Use container height for component height
static int	CONTAINER_WIDTH Use container widht for component height
static int	IGNORE_HIDDEN Instruct layout manager to ignore hidden components
static int	MAXIMUM_HEIGHT Maximise component height
static int	MAXIMUM_WIDTH Maximise component width
static int	MINIMUM_HEIGHT Mimimize component height
static int	MINIMUM_WIDTH Mimimize component width
static int	PREFERRED_HEIGHT Use component preferred height
static int	PREFERRED_WIDTH Use component preferred width
static int	X_AXIS Horizontal orientation
static int	Y_AXIS Vertical orientation

Constructor Summary

BetterBoxLayout()
Creates a horizontal layout where components are their respective preferred sizes clipped to the container height.

BetterBoxLayout(int flags)
Creates a layout based on the flags passed.

Method Summary

void	addLayoutComponent(java.lang.String name, java.awt.Component comp) Not used by this layout manager.
static javax.swing.JComponent	createGlue() Creates a glue object.
static javax.swing.JPanel	createHorizontalBox()
static javax.swing.JComponent	createHorizontalGlue() Creates a horizontal glue object.
static javax.swing.JComponent	createHorizontalStrut(int w) Creates a horizontal strut object of a given width.
static javax.swing.JComponent	createRigidArea(int w, int h) Createas an invisible (transparent), space occupying, non resizable component of given width and height.
static javax.swing.JPanel	createVerticalBox()
static javax.swing.JComponent	createVerticalGlue() Creates a vertical glue object.
static javax.swing.JComponent	createVerticalStrut(int h) Creates a vertical strut object of a given height.
double	getAlignmentY(java.awt.Component c)
void	layoutContainer(java.awt.Container container) Called by the AWT when the specified container needs to be laid out.
java.awt.Dimension	maximumSize(java.awt.Container container)
java.awt.Dimension	minimumLayoutSize(java.awt.Container container)
java.awt.Dimension	preferredLayoutSize(java.awt.Container container)
void	removeLayoutComponent(java.awt.Component comp) Not used by this layout manager.
static void	test() Opens a few test windows to test/debug the layout manager.
static void	test1()
static void	test2()

Methods inherited from class java.lang.Object

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

Field Detail

X_AXIS

public static final int X_AXIS

Horizontal orientation

See Also:

Constant Field Values

Y_AXIS

public static final int Y_AXIS

Vertical orientation

See Also:

Constant Field Values

MINIMUM_HEIGHT

public static final int MINIMUM_HEIGHT

Mimimize component height

See Also:

Constant Field Values

MINIMUM_WIDTH

public static final int MINIMUM_WIDTH

Mimimize component width

See Also:

Constant Field Values

PREFERRED_HEIGHT

public static final int PREFERRED_HEIGHT

Use component preferred height

See Also:

Constant Field Values

PREFERRED_WIDTH

public static final int PREFERRED_WIDTH

Use component preferred width

See Also:

Constant Field Values

MAXIMUM_HEIGHT

public static final int MAXIMUM_HEIGHT

Maximise component height

See Also:

Constant Field Values

MAXIMUM_WIDTH

public static final int MAXIMUM_WIDTH

Maximise component width

See Also:

Constant Field Values

CONTAINER_HEIGHT

public static final int CONTAINER_HEIGHT

Use container height for component height

See Also:

Constant Field Values

CONTAINER_WIDTH

public static final int CONTAINER_WIDTH

Use container widht for component height

See Also:

Constant Field Values

CLIPPED_HEIGHT

public static final int CLIPPED_HEIGHT

Limit component height to container height

See Also:

Constant Field Values

CLIPPED_WIDTH

public static final int CLIPPED_WIDTH

Limit component width to container width

See Also:

Constant Field Values

IGNORE_HIDDEN

public static final int IGNORE_HIDDEN

Instruct layout manager to ignore hidden components

See Also:

Constant Field Values

Constructor Detail

BetterBoxLayout

public BetterBoxLayout()

Creates a horizontal layout where components are their respective preferred sizes clipped to the container height.

BetterBoxLayout

public BetterBoxLayout(int flags)

Creates a layout based on the flags passed.

Parameters:

flags - see class description for usage
if no axis flad is specified X_AXIS is assumed
if no height flag is specified PREFERRED_HEIGHT is assumed

Throws:

java.lang.IllegalArgumentException - if conflicting flags are detected

Method Detail

addLayoutComponent

public void addLayoutComponent(java.lang.String name,
                               java.awt.Component comp)

Not used by this layout manager.

Specified by:

addLayoutComponent in interface java.awt.LayoutManager

Parameters:

name -

comp -

removeLayoutComponent

public void removeLayoutComponent(java.awt.Component comp)

Not used by this layout manager.

Specified by:

removeLayoutComponent in interface java.awt.LayoutManager

Parameters:

comp -

preferredLayoutSize

public java.awt.Dimension preferredLayoutSize(java.awt.Container container)

Specified by:

preferredLayoutSize in interface java.awt.LayoutManager

minimumLayoutSize

public java.awt.Dimension minimumLayoutSize(java.awt.Container container)

Specified by:

minimumLayoutSize in interface java.awt.LayoutManager

maximumSize

public java.awt.Dimension maximumSize(java.awt.Container container)

getAlignmentY

public double getAlignmentY(java.awt.Component c)

layoutContainer

public void layoutContainer(java.awt.Container container)

Called by the AWT when the specified container needs to be laid out.

Specified by:

layoutContainer in interface java.awt.LayoutManager

Parameters:

container - the container to lay out

Throws:

java.awt.AWTError - if a sharing situation is detected between the specified container and one passed to this routine before.

createGlue

public static javax.swing.JComponent createGlue()

Creates a glue object. Glue objects are realy not directional, so this is all you need.

Returns:

a new instance of a glue object

createHorizontalGlue

public static javax.swing.JComponent createHorizontalGlue()

Creates a horizontal glue object. This is provided just for mnemoni and symmetry reasons. Glue objects are real not directional, so you could use createGlue instead.

Returns:

a new instance of a glue object

createVerticalGlue

public static javax.swing.JComponent createVerticalGlue()

Creates a vertical glue object. This is provided just for mnemoni and symmetry reasons. Glue objects are real not directional, so you could use createGlue instead.

Returns:

a new instance of a glue object

createHorizontalStrut

public static javax.swing.JComponent createHorizontalStrut(int w)

Creates a horizontal strut object of a given width. A horizontal strut occupies space in horizontal direction only.

Parameters:

w - the width of the strut

Returns:

a new instance of a strut object with given width

createVerticalStrut

public static javax.swing.JComponent createVerticalStrut(int h)

Creates a vertical strut object of a given height. A vertical strut occupies space in vertical direction only.

Parameters:

h - the height of the strut

Returns:

a new instance of a strut object with given width

createRigidArea

public static javax.swing.JComponent createRigidArea(int w,
                                                     int h)

Createas an invisible (transparent), space occupying, non resizable component of given width and height.

Parameters:

w - the width of the rigid area

h - the height of the rigid area

Returns:

a new instance of a rigid area object with given width and height

createHorizontalBox

public static javax.swing.JPanel createHorizontalBox()

createVerticalBox

public static javax.swing.JPanel createVerticalBox()

test

public static void test()

Opens a few test windows to test/debug the layout manager.

test1

public static void test1()

test2

public static void test2()