com.sun.javafx.scene.control.VirtualScrollBar Maven / Gradle / Ivy
/*
* Copyright (c) 2010, 2024, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package com.sun.javafx.scene.control;
import com.sun.javafx.util.Utils;
import javafx.beans.property.BooleanProperty;
import javafx.beans.property.SimpleBooleanProperty;
import javafx.scene.control.IndexedCell;
import javafx.scene.control.ScrollBar;
import javafx.scene.control.skin.VirtualFlow;
/**
* This custom ScrollBar is used to map the increment & decrement features
* to pixel based scrolling rather than thumb/track based scrolling, if the
* "virtual" attribute is true.
*/
public class VirtualScrollBar extends ScrollBar {
/**************************************************************************
*
* Private fields
*
**************************************************************************/
private final VirtualFlow flow;
private boolean adjusting;
/**************************************************************************
*
* Constructors
*
**************************************************************************/
/**
* Creates a new VirtualScrollBar, for use by the VirtualFlow control.
*/
public VirtualScrollBar(final VirtualFlow flow) {
this.flow = flow;
super.valueProperty().addListener(valueModel -> {
if (isVirtual()/* && oldValue != newValue*/) {
if (adjusting) {
// no-op
} else {
flow.setPosition(getValue());
}
}
});
}
/**************************************************************************
*
* Properties
*
**************************************************************************/
// --- virtual
private BooleanProperty virtual = new SimpleBooleanProperty(this, "virtual");
public final void setVirtual(boolean value) {
virtual.set(value);
}
public final boolean isVirtual() {
return virtual.get();
}
public final BooleanProperty virtualProperty() {
return virtual;
}
/**************************************************************************
*
* Public API
*
**************************************************************************/
/** {@inheritDoc} */
@Override public void decrement() {
if (isVirtual()) {
flow.scrollPixels(-10);
} else {
super.decrement();
}
}
/** {@inheritDoc} */
@Override public void increment() {
if (isVirtual()) {
flow.scrollPixels(10);
} else {
super.increment();
}
}
// this method is called when the user clicks in the scrollbar track, so
// we special-case it to allow for page-up and page-down clicking to work
// as expected.
/** {@inheritDoc} */
@Override public void adjustValue(double pos) {
if (isVirtual()) {
adjusting = true;
if (pos < getValue()) {
flow.scrollPixels(-flow.getViewportLength());
} else {
flow.scrollPixels(flow.getViewportLength());
}
adjusting = false;
} else {
super.adjustValue(pos);
}
}
}