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| /*
* Copyright (c) 2005-2007 Nathanaël Roberts. All Rights Reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* o Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* o Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
* OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/**
* Utilities for focus (behavior, policy, events,...).
*
* @author Nathanaël Roberts
*/
public final class FocusUtils {
/** Only instance of FocusOwnerListener */
private static FocusOwnerListener s_focusOwnerListener;
/**
* Hidden Constructor
*/
private FocusUtils() { }
/**
* Add a listener on property <code>focusOwner</code> in the {@link KeyboardFocusManager}
* in order to have an autoscroll behavior when an hidden component nested in a JScrollPane
* will get the focus.
*/
public static void initFocusTrackerForAutoScroll() {
if (s_focusOwnerListener == null) {
KeyboardFocusManager kfm = KeyboardFocusManager.getCurrentKeyboardFocusManager();
s_focusOwnerListener = new FocusOwnerListener();
kfm.addPropertyChangeListener("focusOwner", s_focusOwnerListener);
}
}
/**
* Activate or deactivate the {@link FocusOwnerListener} for special scrolling actions.
*
* @param active
*/
public static void activateFocusOwnerListener(boolean active) {
if (s_focusOwnerListener == null) {
initFocusTrackerForAutoScroll();
}
if (s_focusOwnerListener != null) {
s_focusOwnerListener.setActive(active);
}
}
/**
* Deactivate the {@link FocusOwnerListener} <code>number*2</code> times.
*/
public static void deactivateFocusOwnerListenerFor(int number) {
if (s_focusOwnerListener == null) {
initFocusTrackerForAutoScroll();
}
if (s_focusOwnerListener != null) {
s_focusOwnerListener.deactivate(number);
}
}
/**
* The FocusOwnerListener.
*/
private static class FocusOwnerListener implements PropertyChangeListener {
private int m_deactivcount;
private int m_deactivate;
private boolean m_active = true;
public void propertyChange(PropertyChangeEvent e) {
// Abort if not active
if (!m_active) {
return;
}
// If deactive one time
if (m_deactivcount < m_deactivate) {
m_deactivcount++;
return;
}
// Scroll to focused element
Object newValue = e.getNewValue();
if (newValue != null && newValue instanceof Component) {
Component comp = (Component) newValue;
JScrollPane jsp = (JScrollPane) SwingUtilities.getAncestorOfClass(JScrollPane.class, comp);
while ((jsp = (JScrollPane) SwingUtilities.getAncestorOfClass(JScrollPane.class, comp)) != null) {
// Do not auto scroll for any other JPanel => but continue in case of nested JScrollPane
if (!(jsp.getViewport().getView() instanceof JPanel)) {
comp = jsp;
continue;
}
// Calculate auto scroll
JViewport jvp = jsp.getViewport();
Rectangle scrollRect = SwingUtilities.convertRectangle(comp, new Rectangle(0, 0, 0, 0), jvp);
if (scrollRect.y + comp.getSize().height > jvp.getViewRect().height) {
scrollRect.y = scrollRect.y - jvp.getViewRect().height + comp.getSize().height;
} else if (scrollRect.y < 0) {
scrollRect.y -= comp.getSize().height;
} else {
scrollRect.y = 0;
}
scrollRect.height = comp.getSize().height + jvp.getHeight();
jvp.scrollRectToVisible(scrollRect);
// Recursive
comp = jsp;
}
}
}
public boolean isActive() {
return this.m_active;
}
public void setActive(boolean active) {
this.m_active = active;
}
public void deactivate(int number) {
this.m_deactivcount = 0;
this.m_deactivate = number * 2;
}
}
} |
