jview
Class JHiddenComponent

java.lang.Object
  jview.JHiddenComponent

public class JHiddenComponent
extends Object

This class helps in adding a button or other components to a frame that disappears from view until the mouse moves over it. It is not using internal frames (to spare the window decoration), but manipulates the layered pane in a RootPaneContainer. This layered pane is assumed to have no layout manager (default case). The following steps are necessary to add (in the example a button) as a hiding component to a top-level window.

• After creating the component, prepare it to be a hiding component by calling prepareHidingComponent(java.awt.Component). This method assigns a mouse listener to the component that brings the component to the foreground on mouse exit and put it to the background on mouse exit.
• After your top-level frame has been prepared for display (strictly speaking when there is a valid size of it), so after pack or setSize or setBounds, add the prepared hiding component to the root pane container either using the compass-contraints in GridBagConstraints (NESW), or by specifying the rule on how the upper left corner of the component should be calculated. If the position you specify should follow window resize events, call the addHidingComponent(java.awt.Component, javax.swing.RootPaneContainer, int, boolean) method with the last argument true, otherwise only the initial size is considered in placement of the hidden component within the frame. The four alignment doubles are the amount of the window size and the amount of the component's size that are used for calculating the upper left corner of the hidden component. For instance, to place a component in the upper right corner (NORTHEAST), the weight on pane width is 1, and the weight of the component size is -1 (height weights zero).
  This method grabs the layered pane from your top-level container and adds the hidden component at the JLayeredPane.FRAME_CONTENT_LAYER in the background. If it should follow resizes, a component listener is added to the layered pane that recalculates the position on component resize events.
• During testing on Java(TM) SE Runtime Environment (build 1.6.0_22-b04), Debian 2.6.26-1-686, it appeared that the component was visible until the mouse moved over it for the first time. Additionally, if the mouse left the window, it again popped up. To force the component to stay hidden also in these circumstances, ensure the hiding of the component by a call to ensureHidingComponent(java.awt.Component, java.awt.Window). This method adds a window listener to the frame that sends the hidden component to the background whenever the window is activated or de-activated.

Nested Class Summary

private static class	JHiddenComponent.ComponentHidden
private static class	JHiddenComponent.MouseHidden
private static class	JHiddenComponent.WindowHidden

Constructor Summary

JHiddenComponent()

Method Summary

static void	addHidingComponent(Component c, RootPaneContainer frame, double panew, double paneh, double compw, double comph, boolean follow) This method adds a (prepared) hiding component to a RootPaneContainer, i.e.
static void	addHidingComponent(Component c, RootPaneContainer frame, int gridbag, boolean follow) This method adds a (prepared) hiding component to a RootPaneContainer, i.e.
static void	ensureHidingComponent(Component c, Window w) This method is only necessary to keep a hiding component hidden if the main frame is shown.
private static Point	getUpLeft(Dimension pane, Dimension comp, double panew, double paneh, double compw, double comph) From four alignment parameters and the size of the frame plus the size of the component, we infer the position where the upper left corner of the hidden component should be.
private static Dimension	inferSize(Component c) Tries to infer the size of the component.
static void	main(String[] arg)
static void	prepareHidingComponent(Component c) This method is called to prepare a component for hiding-until-mouse-over capablitities.
static void	prepareHidingComponent(Component c, int mod) This method is called to prepare a component for hiding-until-mouse-over capablitities.

Methods inherited from class java.lang.Object

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

Constructor Detail

JHiddenComponent

public JHiddenComponent()

Method Detail

prepareHidingComponent

public static void prepareHidingComponent(Component c)

This method is called to prepare a component for hiding-until-mouse-over capablitities. It should be called only once during the life-cycle of the component.

prepareHidingComponent

public static void prepareHidingComponent(Component c,
                                          int mod)

This method is called to prepare a component for hiding-until-mouse-over capablitities. It should be called only once during the life-cycle of the component.

addHidingComponent

public static void addHidingComponent(Component c,
                                      RootPaneContainer frame,
                                      int gridbag,
                                      boolean follow)

This method adds a (prepared) hiding component to a RootPaneContainer, i.e. a frame, window, dialog or applet. It may be a bug, but on display the hidden component might still get visible, unless an appropriate window listener is attached to the frame/dialog/window using #ensureComponentHiding.

To support generic placements, the anchor-constants in GridBagConstraints for absolute values are supported (CENTER plus compass directions). If invalid, center is used.

addHidingComponent

public static void addHidingComponent(Component c,
                                      RootPaneContainer frame,
                                      double panew,
                                      double paneh,
                                      double compw,
                                      double comph,
                                      boolean follow)

This method adds a (prepared) hiding component to a RootPaneContainer, i.e. a frame, window, dialog or applet. It may be a bug, but on display the hidden component might still get visible, unless an appropriate window listener is attached to the frame/dialog/window using #ensureComponentHiding.

To support generic placements, the four placement indicators are used to deduce the upper left corner (UL). A placement in the center would thus require 0.5, 0.5, -0.5, -0.5.

Parameters:

panew - pane width*this=UL x coordinate.

paneh - pane height*this=UL y coordinate.

compw - component width*this: added to UL x (negative allowed).

comph - component height*this: added to UL y (negative allowed).

getUpLeft

private static Point getUpLeft(Dimension pane,
                               Dimension comp,
                               double panew,
                               double paneh,
                               double compw,
                               double comph)

From four alignment parameters and the size of the frame plus the size of the component, we infer the position where the upper left corner of the hidden component should be.

inferSize

private static Dimension inferSize(Component c)

Tries to infer the size of the component. First look at getSize, then try getPreferredSize, is this is inconvenient (<0).

ensureHidingComponent

public static void ensureHidingComponent(Component c,
                                         Window w)

This method is only necessary to keep a hiding component hidden if the main frame is shown.

main

public static void main(String[] arg)
                 throws Exception

Throws:

Exception