Swing Hacks

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Chapter 5, Windows, Dialogs, and Frames

#40 Minimize to a Mini-Frame

HACK

The code declares a MiniMizeHack class, which creates the UI and adds itself

as an

ActionListener to the Minimize and Restore menu items. The mouse

listener implementation is there to control the pop-up menu, but because

the

MiniMizeHack

class hasn’t been added as a listener to any components,

the pop up won’t do anything yet.

Minimize the Frame

The actionPerformed( ) method does the actual switching. This is the meat

of the hack. It tests if the bottom component is visible. If the component is

visible, then this method calls

switchToMini( )

and reshapes the frame to be

smaller. If the bottom component is not visible, then

actionPerformed( )

calls

switchToNormal( )

to reverse the changes:

public void actionPerformed(ActionEvent evt) {

if(bottom.isVisible( )) {

switchToMini( );

} else {

switchToNormal( );

}

}

The magic happens in the switchToMini( ) method. A big part of a mini win-

dow is that it doesn’t have any borders, or at the least it uses custom ones.

Swing does not let you turn off a frame’s borders and window decorations

after the frame has been shown on screen because it might have already allo-

cated immutable system resources. The only way around this limitation is to

seamlessly replace the old frame with a new one:

private Dimension normal_size;

public void switchToMini( ) {

// nuke the old frame and build a new one ...