java - CTabFolder布局控件不渲染

Question

我在 SWT 的 TabFolder 下创建了两个展开栏。我将选项卡文件夹的布局设置为 FillLayout(SWT.HORIZONTAL)。它在选项卡文件夹中显示两个展开栏。 但是当我将选项卡文件夹更改为具有相同布局的 CTabFolder 时，它没有显示 CTabFolder 下的任何展开栏。可能是什么问题？我需要为此设置任何参数吗？请参阅下面的 TabFolder 和 CTabFolder 代码。

TabFolder 代码:

public class Snippet223 {

    public static void main(String[] args) {
        Display display = new Display();
        Shell shell = new Shell(display);
        shell.setLayout(new FillLayout());
        shell.setText("ExpandBar Example");
        final TabFolder folder = new TabFolder(shell, SWT.BORDER);
        folder.setLayout(new FillLayout(SWT.HORIZONTAL));
        ExpandBar bar = new ExpandBar(folder, SWT.V_SCROLL);
        ExpandBar bar1 = new ExpandBar(folder, SWT.V_SCROLL);
        Image image = display.getSystemImage(SWT.ICON_QUESTION);
        // First item
        createContentsForExpandableBar(bar, image);
        createContentsForExpandableBar(bar1, image);
        shell.setSize(400, 350);
        shell.open();
        while (!shell.isDisposed()) {
            if (!display.readAndDispatch()) {
                display.sleep();
            }
        }
        display.dispose();
    }

    private static void createContentsForExpandableBar(ExpandBar bar,
            Image image) {
        Composite composite = new Composite(bar, SWT.NONE);
        GridLayout layout = new GridLayout();
        layout.marginLeft = layout.marginTop = layout.marginRight = layout.marginBottom = 10;
        layout.verticalSpacing = 10;
        composite.setLayout(layout);
        Button button = new Button(composite, SWT.PUSH);
        button.setText("SWT.PUSH");
        button = new Button(composite, SWT.RADIO);
        button.setText("SWT.RADIO");
        button = new Button(composite, SWT.CHECK);
        button.setText("SWT.CHECK");
        button = new Button(composite, SWT.TOGGLE);
        button.setText("SWT.TOGGLE");
        ExpandItem item0 = new ExpandItem(bar, SWT.NONE, 0);
        item0.setText("What is your favorite button");
        item0.setHeight(composite.computeSize(SWT.DEFAULT, SWT.DEFAULT).y);
        item0.setControl(composite);
        item0.setImage(image);
    }

}

CTabFolder 代码:

public class Snippet223 {

    public static void main(String[] args) {
        Display display = new Display();
        Shell shell = new Shell(display);
        shell.setLayout(new FillLayout());
        shell.setText("ExpandBar Example");
        final CTabFolder folder = new CTabFolder(shell, SWT.BORDER);
        folder.setLayout(new FillLayout(SWT.HORIZONTAL));
        ExpandBar bar = new ExpandBar(folder, SWT.V_SCROLL);
        ExpandBar bar1 = new ExpandBar(folder, SWT.V_SCROLL);
        Image image = display.getSystemImage(SWT.ICON_QUESTION);
        // First item
        createContentsForExpandableBar(bar, image);
        createContentsForExpandableBar(bar1, image);
        shell.setSize(400, 350);
        shell.open();
        while (!shell.isDisposed()) {
            if (!display.readAndDispatch()) {
                display.sleep();
            }
        }
        display.dispose();
    }

    private static void createContentsForExpandableBar(ExpandBar bar,
            Image image) {
        Composite composite = new Composite(bar, SWT.NONE);
        GridLayout layout = new GridLayout();
        layout.marginLeft = layout.marginTop = layout.marginRight = layout.marginBottom = 10;
        layout.verticalSpacing = 10;
        composite.setLayout(layout);
        Button button = new Button(composite, SWT.PUSH);
        button.setText("SWT.PUSH");
        button = new Button(composite, SWT.RADIO);
        button.setText("SWT.RADIO");
        button = new Button(composite, SWT.CHECK);
        button.setText("SWT.CHECK");
        button = new Button(composite, SWT.TOGGLE);
        button.setText("SWT.TOGGLE");
        ExpandItem item0 = new ExpandItem(bar, SWT.NONE, 0);
        item0.setText("What is your favorite button");
        item0.setHeight(composite.computeSize(SWT.DEFAULT, SWT.DEFAULT).y);
        item0.setControl(composite);
        item0.setImage(image);
    }

}

Answer 1

您需要在 TabFolder/CTabFolder 下创建一个 TabItem/CTabItem 并向其中添加内容。您不应该在选项卡文件夹本身上设置布局。来自 CTabFolder 的 JavaDoc:

Note that although this class is a subclass of Composite, it does not make sense to set a layout on it.