/*******************************************************************************
* Copyright (c) 2000, 2016 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.swt.snippets;
/*
* ScrolledComposite snippet: use a ScrolledComposite to scroll a disabled
* control. Note that this goes against conventional UI behaviour, where
* disabling a control typically disables its scrollbars as well.
*
* For a list of all SWT example snippets see
* http://www.eclipse.org/swt/snippets/
*/
import org.eclipse.swt.*;
import org.eclipse.swt.custom.*;
import org.eclipse.swt.events.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.widgets.*;
public class Snippet322 {
public static void main (String[] args) {
final Display display = new Display ();
Shell shell = new Shell (display);
shell.setBounds (10, 10, 300, 300);
final ScrolledComposite sc = new ScrolledComposite (shell, SWT.VERTICAL);
sc.setBounds (10, 10, 280, 200);
final int clientWidth = sc.getClientArea ().width;
final Tree tree = new Tree (sc, SWT.NONE);
for (int i = 0; i < 99; i++) {
TreeItem item = new TreeItem (tree, SWT.NONE);
item.setText ("item " + i);
new TreeItem (item, SWT.NONE).setText ("child");
}
sc.setContent (tree);
int prefHeight = tree.computeSize (SWT.DEFAULT, SWT.DEFAULT).y;
tree.setSize (clientWidth, prefHeight);
/*
* The following listener ensures that the Tree is always large
* enough to not need to show its own vertical scrollbar.
*/
tree.addTreeListener (new TreeListener () {
@Override
public void treeExpanded (TreeEvent e) {
int prefHeight = tree.computeSize (SWT.DEFAULT, SWT.DEFAULT).y;
tree.setSize (clientWidth, prefHeight);
}
@Override
public void treeCollapsed (TreeEvent e) {
int prefHeight = tree.computeSize (SWT.DEFAULT, SWT.DEFAULT).y;
tree.setSize (clientWidth, prefHeight);
}
});
/*
* The following listener ensures that a newly-selected item
* in the Tree is always visible.
*/
tree.addSelectionListener(new SelectionAdapter() {
@Override
public void widgetSelected(SelectionEvent e) {
TreeItem [] selectedItems = tree.getSelection();
if (selectedItems.length > 0) {
Rectangle itemRect = selectedItems[0].getBounds();
Rectangle area = sc.getClientArea();
Point origin = sc.getOrigin();
if (itemRect.x < origin.x || itemRect.y < origin.y
|| itemRect.x + itemRect.width > origin.x + area.width
|| itemRect.y + itemRect.height > origin.y + area.height) {
sc.setOrigin(itemRect.x, itemRect.y);
}
}
}
});
/*
* The following listener scrolls the Tree one item at a time
* in response to MouseWheel events.
*/
tree.addListener(SWT.MouseWheel, event -> {
Point origin = sc.getOrigin();
if (event.count < 0) {
origin.y = Math.min(origin.y + tree.getItemHeight(), tree.getSize().y);
} else {
origin.y = Math.max(origin.y - tree.getItemHeight(), 0);
}
sc.setOrigin(origin);
});
Button disableButton = new Button (shell, SWT.PUSH);
disableButton.setBounds (10, 220, 120, 30);
disableButton.setText ("Disable");
disableButton.addListener (SWT.Selection, event -> tree.setEnabled(false));
Button enableButton = new Button (shell, SWT.PUSH);
enableButton.setBounds (140, 220, 120, 30);
enableButton.setText ("Enable");
enableButton.addListener (SWT.Selection, event -> tree.setEnabled(true));
shell.open ();
while (!shell.isDisposed ()) {
if (!display.readAndDispatch ()) display.sleep ();
}
display.dispose ();
}
}
