Tray Tutorial

Tray和TrayItem是指在任务栏上的能代表程序的图标，和前面提到的TaskBar类似。比如我们常见的QQ，Skype等程序运行之后，在屏幕的右下角会有一个图标。

先看一个示例吧：

	Display display = new Display();
	final Shell shell = new Shell(display);
	shell.setText("Tray Tutorial");
	shell.setSize(300, 200);

	RowLayout layout = new RowLayout(SWT.HORIZONTAL);
	layout.spacing = 0;
	shell.setLayout(layout);

	Image image = new Image(display,
			TrayTutorial.class.getResourceAsStream("task.gif"));

	CLabel label = new CLabel(shell, SWT.CENTER);
	Tray tray = display.getSystemTray();
	if (tray == null) {
		label.setText("This platform does NOT support the tray.");
	} else {
		label.setText("Please visit the icon ");
		new CLabel(shell, SWT.CENTER).setImage(image);
		new CLabel(shell, SWT.CENTER).setText(" on System TaskBar.");
		// Create tray item.
		TrayItem item = new TrayItem(tray, SWT.NONE);
		// Set images.
		item.setImage(image);
		item.setHighlightImage(image);

		// Add tool tip.
		final ToolTip toolTip = new ToolTip(shell, SWT.BALLOON);
		toolTip.setText("Foxes vs. Dogs");
		toolTip.setMessage("A quick brown fox jumps over the lazy dog.");
		item.setToolTip(toolTip);

		// Add Selection and DefaultSelection Listener.
		item.addSelectionListener(new SelectionListener() {

			@Override
			public void widgetSelected(SelectionEvent e) {
				shell.moveAbove(null);
			}

			@Override
			public void widgetDefaultSelected(SelectionEvent e) {
				toolTip.setVisible(true);
			}
		});

		// Add Menu Listener.
		final Menu menu = new Menu(shell, SWT.POP_UP);
		for (int i = 0; i < 5; i++) {
			MenuItem menuItem = new MenuItem(menu, SWT.NONE);
			menuItem.setImage(image);
			menuItem.setText("MenuItem - " + i);
		}
		new MenuItem(menu, SWT.SEPARATOR);
		MenuItem exit = new MenuItem(menu, SWT.NONE);
		exit.setText("Exit");
		exit.addListener(SWT.Selection, new Listener() {

			@Override
			public void handleEvent(Event event) {
				shell.dispose();
			}
		});

		item.addMenuDetectListener(new MenuDetectListener() {

			@Override
			public void menuDetected(MenuDetectEvent e) {
				menu.setVisible(true);
			}
		});
	}

	shell.open();
	while (!shell.isDisposed()) {
		if (!display.readAndDispatch()) {
			display.sleep();
		}
	}
	image.dispose();
	display.dispose();

运行此段代码，会在TaskBar上出现一个图标，双击会出现ToolTip，右键点击会出现菜单。

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参考资料：

• Tray, TrayItem snippets
• Sample code and further information

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