当看到下拉列表时，在组合查看器外部单击鼠标时会生成什么事件？

Question

我有ComboViewer。在看到下拉的同时，我在查看器外部点击了鼠标（而不是在查看器的任何部分）。下拉列表中的第一项填充在框中。当这个人群发生时会产生什么事件？

我在comboviewer上尝试了SelectionChangedListener，在浏览器的组合框上尝试了FocusListener，KeyListener和SelectionListener。这些都没有帮助。

我的要求是根据组合框中的内容启用和禁用按钮。组合为空，禁用按钮，否则启用它。

public class CartoonAnimalCombo {
public class Cartoon {
    private String firstName;
    private String type;

    public Cartoon(String firstName, String lastName) {
        this.firstName = firstName;
        this.type = lastName;
    }

    public String getFirstName() {
        return firstName;
    }

    public String getType() {
        return type;
    }
}

public static void main(String[] argv) {
    new CartoonAnimalCombo();
}

private String inputText;

CartoonAnimalCombo() {

    Display d = new Display();
    Shell parent = new Shell(d);
    parent.setSize(250, 250);
    GridLayout layout = new GridLayout(2, false);
    parent.setLayout(layout);

    Label label = new Label(parent, SWT.NONE);
    label.setText("Select a character:");
    final ComboViewer viewer = new ComboViewer(parent, SWT.NONE);

    viewer.setContentProvider(ArrayContentProvider.getInstance());
    viewer.setLabelProvider(new LabelProvider() {
        @Override
        public String getText(Object element) {
            if (element instanceof Cartoon) {
                Cartoon person = (Cartoon) element;
                return person.getFirstName();
            }
            return super.getText(element);
        }
    });

    final Cartoon[] cartoons = new Cartoon[] { new Cartoon("Mickey", "Mouse"), new Cartoon("Donald", "Duck"),
            new Cartoon("Pluto", "Dog"), new Cartoon("Chip", "Squirrel"), new Cartoon("Dale", "Squirrel") };

    viewer.setInput(cartoons);
    final ArrayList<Cartoon> tempVar = new ArrayList<Cartoon>();
    final Combo combo = viewer.getCombo();
    combo.addKeyListener(new KeyAdapter() {
        @Override
        public void keyReleased(KeyEvent e) {
            if (e.keyCode != SWT.ARROW_DOWN && e.keyCode != SWT.ARROW_UP && e.keyCode != SWT.CR) {
                tempVar.clear();
                String text = combo.getText();
                if (text != null && !text.isEmpty()) {
                    setSearchText(text);
                    for (Cartoon var : cartoons) {
                        if (var.getFirstName().matches(inputText)) {
                            tempVar.add(var);
                        }
                    }
                }
                if (text.isEmpty()) {
                    tempVar.addAll(Arrays.asList(cartoons));
                }
                viewer.setInput(tempVar.toArray());
                combo.setListVisible(true);
                combo.setText(text);
                combo.setSelection(new Point(text.length(), text.length()));
            }
        }
    });
    Label lastName = new Label(parent, SWT.NONE);
    lastName.setText("Type of Animal:");
    final Text textbox = new Text(parent, SWT.BORDER);
    viewer.addSelectionChangedListener(new ISelectionChangedListener() {
        @Override
        public void selectionChanged(SelectionChangedEvent event) {
            IStructuredSelection selection = (IStructuredSelection) event.getSelection();
            if (selection.size() > 0) {
                textbox.setText(((Cartoon) selection.getFirstElement()).getType());
            }
        }
    });

    parent.open();
    while (!parent.isDisposed()) {
        if (!d.readAndDispatch()) {
            d.sleep();
        }
    }
    d.dispose();
}

public void setSearchText(String searchText) {
    if (searchText == null || searchText.isEmpty()) {
        this.inputText = ".*"; //$NON-NLS-1$
    } else {
        this.inputText = searchText + ".*"; //$NON-NLS-1$
    }
}

}