Bug 60489

Description Carolyn MacLeod 2004-04-29 15:18:39 EDT

200404270800 (This bug has been broken out of bug 10846).

Both Views and Editors are "in" a CTabFolder, however they are not actually 
children of the CTabFolder (they are siblings), so traversal events that go to 
the Views aren't propagated to the CTabFolder. This is a problem with the 
traversal events for PAGE_NEXT and PAGE_PREVIOUS. (Which are sent when the 
user types Ctrl+PgDown or Ctrl+PgUp).

Here is an SWT snippet that shows how these traversal events can be forwarded 
from the View ("tabContents") to the CTabFolder ("tabFolder"). The relevant 
lines of code from the snippet are:

tabContents.addTraverseListener(new TraverseListener() {
	public void keyTraversed(TraverseEvent e) {
		switch (e.detail) {
			case SWT.TRAVERSE_PAGE_NEXT:
			case SWT.TRAVERSE_PAGE_PREVIOUS:
				tabFolder.traverse(e.detail);
				e.detail = SWT.TRAVERSE_NONE;
				e.doit = true;
		}
	}
});

You just have to figure out which controls are "tabContents" and "tabFolder".
The best place to hook the traverse listener is on the fake child(ren) (i.e. 
actually sibling) of the CTabFolder(s) so that they can forward the "page 
next/previous" traversal to the CTabFolder. The line "e.detail = 
SWT.TRAVERSE_NONE" tells the fake child not to do any traversal itself, and 
the line "e.doit = true" says that the traversal has been handled by someone, 
so don't pass it to anybody else.

The snippet emulates eclipse's "tabfolder has siblings that act like children" 
story. While it can be said that this story may have other problems in future 
where additional traversal types should be forwarded, for now I recommend just 
forwarding this one traversal (page next/previous). I also recommend 
checking "instanceof CTabFolder" before forwarding (i.e. be very specific). 
Forwarding other traversals should be done carefully on an as-needed basis.

(I will attach the 7 little gifs that the snippet uses for a tool bar).


import org.eclipse.swt.*;
import org.eclipse.swt.widgets.*;
import org.eclipse.swt.events.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.layout.*;
import org.eclipse.swt.custom.*;

public class EclipseCTabFolderAccessibilityTest {
	static Display display;
	static Shell shell;
	static CTabFolder tabFolder;
	static boolean sibling = true; // whether tab content is child or 
sibling of tab folder
	static Point maxSize;
	static Composite selectedContents;
	
	public static void main(String[] args) {
		display = new Display();
		shell = new Shell(display);
		if (!sibling) shell.setLayout(new GridLayout());
		shell.setText("Eclipse CTabFolder Accessibility Test");
		maxSize = new Point(0, 0);
		tabFolder = new CTabFolder(shell, SWT.BORDER);
		for (int tabNumber = 0; tabNumber < 5; tabNumber++) {
			CTabItem item = new CTabItem(tabFolder, SWT.NULL);
			item.setText("CTab &" + tabNumber);
			Composite tabContents = new Composite(sibling ? 
(Composite) shell : (Composite) tabFolder, SWT.NONE);
			tabContents.setLayout(new GridLayout());
			createTabContents(tabContents, tabNumber);
			if (sibling) {
				tabContents.addTraverseListener(new 
TraverseListener() {
					public void keyTraversed(TraverseEvent 
e) {
						switch (e.detail) {
							case 
SWT.TRAVERSE_PAGE_NEXT:
							case 
SWT.TRAVERSE_PAGE_PREVIOUS:
							
	tabFolder.traverse(e.detail);
								e.detail = 
SWT.TRAVERSE_NONE;
								e.doit = true;
						}
					}
				});
				tabContents.pack();
				Point size = tabContents.getSize();
				if (size.x > maxSize.x || size.y > maxSize.y) 
maxSize = size;
				tabContents.setVisible(false);
				item.setData(tabContents);
			} else {
				item.setControl(tabContents);
			}
		}
		tabFolder.moveBelow(null);
		if (sibling) {
			tabFolder.setSize(tabFolder.computeSize(maxSize.x, 
maxSize.y));
			shell.addControlListener(new ControlAdapter() {
				public void controlResized(ControlEvent e) {
					tabFolder.setBounds(shell.getClientArea
());
					CTabItem item = tabFolder.getSelection
();
					if (item == null) return;
					setItemBounds(item);
				}
			});
			tabFolder.addSelectionListener(new SelectionAdapter() {
				public void widgetSelected(SelectionEvent e) {
					showItem((CTabItem) e.item);
				}
			});
		} else {
			new Button(shell, SWT.PUSH).setText("Hello");
		}
		shell.pack();
		shell.open();
		tabFolder.setSelection(0);
		if (sibling) showItem(tabFolder.getItem(0));
		
		while (!shell.isDisposed()) {
			if (!display.readAndDispatch()) display.sleep();
		}
	}
	
	static void setItemBounds(CTabItem item) {
		Composite tabContents = (Composite) item.getData();
		tabContents.setBounds(tabFolder.getClientArea());
	}

	static void showItem(CTabItem item) {
		Composite tabContents = (Composite) item.getData();
		tabContents.setBounds(tabFolder.getClientArea());
		if (selectedContents != null) selectedContents.setVisible
(false);
		tabContents.setVisible(true);
		selectedContents = tabContents;
		tabContents.setFocus();
	}

	static void createTabContents(Composite tabContents, int tabNumber) {
		Label itemLabel = new Label(tabContents, SWT.NONE);
		itemLabel.setText("Label for CTabItem " + tabNumber + " is a 
child of a composite");
		switch (tabNumber) {
			case 0:
				Text itemText = new Text(tabContents, 
SWT.MULTI | SWT.BORDER);
				itemText.setLayoutData(new GridData
(GridData.FILL_BOTH));
				itemText.setText("\nText for CTabItem " + 
tabNumber + "\n\n\n");
				break;
			case 1:
				Button itemCheck = new Button(tabContents, 
SWT.CHECK);
				itemCheck.setLayoutData(new GridData
(GridData.FILL_HORIZONTAL));
				itemCheck.setText("Checkbox for CTabItem " + 
tabNumber);
				break;
			case 2:
				Tree itemTree = new Tree(tabContents, 
SWT.SINGLE);
				itemTree.setLayoutData(new GridData
(GridData.FILL_BOTH));
				for (int i = 0; i < 4; i++) {
					TreeItem treeItem = new TreeItem 
(itemTree, SWT.NULL);
					treeItem.setText ("TreeItem " + i + " 
for CTabItem " + tabNumber);
					for (int j = 0; j < 3; j++) {
						new TreeItem(treeItem, 
SWT.NONE).setText("TreeItem " + i + j + " for CTabItem " + tabNumber);
					}
				}
				break;
			case 3:
				Table itemTable = new Table(tabContents, 
SWT.SINGLE);
				itemTable.setLayoutData(new GridData
(GridData.FILL_BOTH));
				itemTable.setHeaderVisible(true);
				itemTable.setLinesVisible(true);
				for (int col = 0; col < 2; col++) {
					TableColumn column = new TableColumn
(itemTable, SWT.NONE);
					column.setText("Column " + col);
				}
				for (int i = 0; i < 4; i++) {
					TableItem tableItem = new TableItem 
(itemTable, SWT.NULL);
					tableItem.setText (new String [] 
{"TableItem " + i, "for CTabItem " + tabNumber});
				}
				for (int col = 0; col < 2; col++) {
					itemTable.getColumn(col).pack();
				}
				break;
			case 4:
				ToolBar itemToolBar = new ToolBar(tabContents, 
SWT.FLAT);
				itemToolBar.setLayoutData(new GridData
(GridData.FILL_HORIZONTAL));
		        String[] toolBarFileNames = new String [] 
{"save", "saveas", "printer", "debug", "run", "search", "opentype"};
				for (int tool = 0; tool < 
toolBarFileNames.length; tool++) {
					String fileName = toolBarFileNames
[tool];
		           	ToolItem item = new ToolItem(itemToolBar, 
SWT.PUSH);
		            item.setImage(createToolBarIcon(display, 
fileName));
		            item.setToolTipText(fileName + " ToolItem for 
CTabItem " + tabNumber);
				}
				break;
		}
	}

	static Image createToolBarIcon(Display display, String fileName) {
		try {
			ImageData source = new ImageData
(AccessibleToolBarTest.class.getResourceAsStream(fileName + ".gif"));
			ImageData mask = source.getTransparencyMask();
			return new Image(display, source, mask);
		} catch (Exception e) {
		}
		return null;
	}
}