Question

我正在用Java和SWT创建一个应用程序，我遇到了问题。我想将ExpandBar放入GridLayout。一切都没问题，而我没有折叠展开栏。当我这样做时，它会正常碰撞，但复合材料不会重新铺设。下面的屏幕应该解释我的问题：

崩溃前：
Before collapse
崩溃后：
After collapse

我尝试了一些技巧，例如：

bar.addExpandListener(new ExpandListener() {
    public void itemExpanded(ExpandEvent e) {
        item0.setHeight(composite.computeSize(SWT.DEFAULT, SWT.DEFAULT).y);
        gridData2.heightHint = composite.computeSize(SWT.DEFAULT,
                SWT.DEFAULT).y;
        comp.layout(true, true);
    }

    public void itemCollapsed(ExpandEvent e) {
        item0.setHeight(item0.getHeaderHeight());
        gridData2.heightHint = item0.getHeaderHeight();
        comp.layout(true, true);
    }
});

尽管它不起作用。这是SSCCE：

package stackoverflow;

import org.eclipse.jface.window.Window;
import org.eclipse.swt.SWT;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.ExpandBar;
import org.eclipse.swt.widgets.ExpandItem;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Tree;

public class MainWindowSWT extends Window {

    public MainWindowSWT() {
        super((Shell)null);

        setBlockOnOpen(true);
        open();
        Display.getCurrent().dispose();
    }

    @Override
    protected Control createContents(Composite parent) {
        final Composite comp = new Composite(getShell(), 0);

        GridLayout layout = new GridLayout(1, true);
        comp.setLayout(layout);

        Tree tree = new Tree(comp, SWT.BORDER | SWT.H_SCROLL | SWT.V_SCROLL);
        GridData gridData = new GridData();
        gridData.verticalAlignment = GridData.FILL;
        gridData.verticalSpan = 2;
        gridData.grabExcessVerticalSpace = true;
        gridData.horizontalAlignment = GridData.FILL;
        gridData.grabExcessHorizontalSpace = true;
        tree.setLayoutData(gridData);

        final ExpandBar bar = new ExpandBar(comp, SWT.V_SCROLL);
        final Composite composite = new Composite(bar, SWT.NONE);
        GridLayout gridLayout = new GridLayout();
        gridLayout.verticalSpacing = 10;
        composite.setLayout(gridLayout);
        Button button = new Button(composite, SWT.PUSH);
        button.setText("SWT.PUSH");
        final ExpandItem item0 = new ExpandItem(bar, SWT.NONE, 0);
        item0.setText("Test");
        item0.setHeight(composite.computeSize(SWT.DEFAULT, SWT.DEFAULT).y);
        item0.setControl(composite);

        item0.setExpanded(true);

        final GridData gridData2 = new GridData();
        gridData2.horizontalAlignment = GridData.FILL;
        gridData2.grabExcessHorizontalSpace = true;
        bar.setLayoutData(gridData2);

        return parent;
    }
}

Ubuntu 12.04.1 amd64，SWT 3.7.2。

提前致谢。

//顺便说一句：我不想调整shell的大小。我想调整展开栏上方的树的大小。

Answer 1

好的，所以我找到了一个有点hacky的解决方案，但它确实有效：

public class MainWindowSWT {

    public static void main(String[] args) {
        final Display display = new Display();
        final Shell shell = new Shell(display);
        shell.setLayout(new FillLayout());
        shell.setText("ExpandBar Example");
        final ExpandBar bar = new ExpandBar(shell, SWT.NONE);

        final Composite composite = new Composite(bar, SWT.NONE);
        GridLayout layout = new GridLayout();
        composite.setLayout(layout);
        Button button = new Button(composite, SWT.PUSH);
        button.setText("SWT.PUSH");
        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.setExpanded(true);

        bar.setSpacing(8);

        bar.addExpandListener(new ExpandListener() {

            @Override
            public void itemExpanded(ExpandEvent e) {
                if (e.item instanceof ExpandItem) {
                    ExpandItem item = (ExpandItem) e.item;
                    shell.setSize(shell.getSize().x, shell.getSize().y + item.getHeight());
                }
            }

            @Override
            public void itemCollapsed(ExpandEvent e) {
                if (e.item instanceof ExpandItem) {
                    ExpandItem item = (ExpandItem) e.item;
                    shell.setSize(shell.getSize().x, shell.getSize().y - item.getHeight());
                }
            }
        });
        shell.pack();
        shell.open();
        while (!shell.isDisposed()) {
            if (!display.readAndDispatch()) {
                display.sleep();
            }
        }
        display.dispose();
    }
}

基本上，您强制shell增加/减少其高度以反映更改。我希望有一种更简单/更漂亮的方式，但现在我想不出任何东西。

部分基于this答案，但没有使用线程。

Answer 2

我得到了它的工作，但我对这个解决方案不满意......

bar.addExpandListener(new ExpandAdapter() {

    @Override
    public void itemCollapsed(ExpandEvent e) {
        new Thread(new Runnable() {

            @Override
            public void run() {
                try {
                    synchronized (this) {
                        wait(250);
                    }
                } catch (InterruptedException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                Display.getDefault().asyncExec(new Runnable() {
                    public void run() {
                        layout();

                    }
                });
            }
        }).start();
    }

    @Override
    public void itemExpanded(ExpandEvent e) {
        new Thread(new Runnable() {

            @Override
            public void run() {
                try {
                    synchronized (this) {
                        wait(250);
                    }
                } catch (InterruptedException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                Display.getDefault().asyncExec(new Runnable() {
                    public void run() {
                        layout();

                    }
                });
            }
        }).start();
    }
});

ExpandBar与GridLayout错误地工作

2 个答案: