Swing Hacks

Add Status Bars to Windows #36

Chapter 5, Windows, Dialogs, and Frames

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189

HACK

The first section draws the gray lines at the top. Midway through, y is reset

based on the panel height, and then the bottom lines are drawn.

Add the Corner Icon

Next, you need to add the resize icon—preferably made to resemble real

Windows resize icons

[Hack #36]. Make a JLabel for the corner icon and add

the icon to it. Since this hack is mimicking the Explorer status bar, use the

TriangleSquareWindowsCornerIcon. Also, remember to set the label opacity to

false. This makes the status panel background show through the icon:

JLabel resizeIconLabel = new JLabel(new TriangleSquareWindowsCornerIcon( ));

resizeIconLabel.setOpaque(false);

Now, you need to add the label to the panel. You need the resize icon to be

at the right, on the bottom of the bar. For this to work, set the

JStatusBar

layout to a BorderLayout. Then create another panel called rightPanel and

set its

layout to BorderLayout as well. Add the rightPanel to the status bar,

to the east; add the resize icon to the

rightPanel, to the south. Don’t forget

to set the

rightPanel’s opacity to false as well. This will place the icon on

the bottom right of the status bar:

JPanel rightPanel = new JPanel(new BorderLayout( ));

rightPanel.setOpaque(false);

rightPanel.add(resizeIconLabel, BorderLayout.SOUTH);

add(rightPanel, BorderLayout.EAST);

While you’re at it, create another panel and name it contentPanel. Add this

to the center of the status bar. You’ll use this in the next few sections to add

the rest of the components:

contentPanel = new JPanel( );

contentPanel.setOpaque(false);

add(contentPanel, BorderLayout.CENTER);

Add the Left Component

Now that the contentPanel is in place, you need to configure it to hold all of

the components you’re going to add to the status bar. Remember that the

status bar has several components on the righthand side (just to the left of

the resize icon) that don’t resize.

It’s actually possible for these components to resize, but

standard Windows behavior is to have the size stay the same

and center text.

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Chapter 5, Windows, Dialogs, and Frames

#36 Add Status Bars to Windows

HACK

There are also a bunch of separators between each of the righthand compo-

nents. And on the left, the status bar has a main component that takes up all

of the space left over after the righthand components (yes, it’s rather confus-

ing; read this section again and you’ll get it).

You could get most of this behavior with a bunch of nested panels and lay-

outs. But it’s easier to use a single layout manager that can handle all of

these, such as

FormLayout from JGoodies. I don’t want to get too detailed

about

FormLayout, so feel free to check out http://www.jgoodies.com for more

info. You’ll need to download JGoodies Forms from the JGoodies site and

put its JAR file (forms-1.0.5.jar as of this writing) in your classpath. Here is

the code to create a new

FormLayout and set it on the contentPanel:

layout = new com.jgoodies.forms.layout.FormLayout(

"2dlu, pref:grow",

"3dlu, fill:10dlu, 2dlu");

contentPanel.setLayout(layout);

FormLayout is essentially an advanced grid, typically configured by passing in

strings that describe the row and column contents in a heavily condensed

syntax. So, you need to configure the grid columns and rows and then add

the components to the appropriate locations. It’s a simplistic approach that

is really powerful.

The first line—

2dlu, pref:grow—creates two columns: one column is two

dialog units (

dlu in the code) wide and another column that grows. This is

for the left component (which needs to grow), and is it going to be added to

the second column (the first column is there simply to create a space). The

dialog unit system used for this space is based on the pixel size of the dialog

font, meaning it can grow and shrink as fonts and resolutions change. Over-

all, this creates better and more consistently sized components and win-

dows than using absolute pixel measurements.

The second line—

3dlu, fill:10dlu, 2dlu—creates the rows for the layout. In

this case, it adds a three dialog unit space at the top, a two dialog unit space

at the bottom, and fills the rest of the space with the component you add.

Now, add the left component. When you add components to a

FormLayout-

enabled panel, you need to use a JGoodies

CellConstraints object. You can

use the simple

CellConstraints that takes an x- and y-coordinate. In this

case, the coordinate is (2,2) because

FormLayout starts counting at 1 and

you’re skipping the first column and row to create space. Here is the code:

public void setMainLeftComponent(JComponent component){

contentPanel.add(component, new CellConstraints(2, 2));

}