java - SWT FileDialog 打开问题

Question

我需要打开一个 FileDialog，以便在使用 Java 7 的 Windows 7 Home 上使用 SWT 打开文件。我需要在按下 BrowseBtn1 按钮 (SWT) 时打开此 FileDialog。我为此使用 addSelectionListener 。这是正确的方法吗？如果是，为什么我的对话框在没有遇到任何运行时错误时无法打开。我根本不使用 AWT，只使用 SWT。

import org.eclipse.swt.*;
import org.eclipse.swt.widgets.*;
import org.eclipse.swt.widgets.FileDialog;
import org.eclipse.swt.events.*;
import org.eclipse.swt.graphics.FontData;
import org.eclipse.swt.layout.*;

public class MySwtApp {
    public static Display display;
    public static Shell shell;

    public static void main(String[] args) {

        display = new Display ();
        shell = new Shell (display);
        shell.setText("MY TITLE");
        GridLayout gridLayout = new GridLayout (3, false);
        shell.setLayout (gridLayout);

        Label Label1 = new Label (shell, SWT.NONE);
        Label1.setText ("Select Message ");
        GridData data = new GridData (200, SWT.DEFAULT);
        Label1.setLayoutData (data);

        Combo Combo1 = new Combo (shell, SWT.NONE);
        Combo1.setItems (new String [] {"Option A", 
                "Option B"});
        // CaseStudyCombo.setText ("CaseStudyCombo");
        data = new GridData (200, SWT.DEFAULT);
        Combo1.setLayoutData (data);
        Combo1.addListener (SWT.DefaultSelection, new Listener () {
            public void handleEvent (Event e) {
                System.out.println (e.widget + " - Default Selection");
            }
        });

        Label emptyLabel = new Label (shell, SWT.NONE);
        emptyLabel.setText ("");
        data = new GridData (50, SWT.DEFAULT);
        emptyLabel.setLayoutData (data);

        Label Label2 = new Label (shell, SWT.NONE);
        Label2.setText ("Next Message: ");
        data = new GridData (200, SWT.DEFAULT);
        Label2.setLayoutData (data);

        final Text text4 = new Text (shell, SWT.BORDER);
        text4.setText ("");
        data = new GridData (215, SWT.DEFAULT);
        text4.setLayoutData (data);

        Button BrowseBtn1 = new Button (shell, SWT.PUSH);
        BrowseBtn1.setText ("Browse");
        data = new GridData (80, SWT.DEFAULT);
        BrowseBtn1.setLayoutData (data);
        BrowseBtn1.addSelectionListener(new SelectionAdapter() {
            String result = "";
            public void WidgetSelected(SelectionEvent e) {
                FileDialog dialog = new FileDialog (shell, SWT.OPEN);
                dialog.setFilterExtensions(new String [] {"*.html"});
                //dialog.setFilterPath("c:\\temp");
                result = dialog.open();
                text4.setText(result);
            }
        });

        Label Label3 = new Label (shell, SWT.NONE);
        Label3.setText ("Message Label 3: ");
        data = new GridData (200, SWT.DEFAULT);
        Label3.setLayoutData (data);

        Text text5 = new Text (shell, SWT.BORDER);
        text5.setText ("");
        data = new GridData (215, SWT.DEFAULT);
        text5.setLayoutData (data);

        Button BrowseBtn2 = new Button (shell, SWT.PUSH);
        BrowseBtn2.setText ("Browse");
        data = new GridData (80, SWT.DEFAULT);
        BrowseBtn2.setLayoutData (data);

        Label Label4 = new Label (shell, SWT.NONE);
        Label4.setText ("Message Label 4: ");
        data = new GridData (200, SWT.DEFAULT);
        Label4.setLayoutData (data);

        Combo Combo2 = new Combo (shell, SWT.NONE);
        Combo2.setText ("Options");
        data = new GridData (200, SWT.DEFAULT);
        Combo2.setLayoutData (data);

        Button searchBtn1 = new Button (shell, SWT.PUSH);
        searchBtn1.setText ("Search");
        data = new GridData (80, SWT.DEFAULT);
        searchBtn1.setLayoutData (data);

        Combo Combo3 = new Combo (shell, SWT.NONE);
        // CaseStudyCombo.setItems (new String [] {"Item 1", "Item 2", "Item 2"});
        Combo3.setText ("Options:");
        data = new GridData (200, SWT.DEFAULT);
        Combo3.setLayoutData (data);

        Combo Combo4 = new Combo (shell, SWT.NONE);
        Combo4.setText ("Options:");
        data = new GridData (200, SWT.DEFAULT);
        Combo4.setLayoutData (data);

        Button showDetailsBtn = new Button (shell, SWT.PUSH);
        showDetailsBtn.setText ("Show Details");
        data = new GridData (80, SWT.DEFAULT);
        showDetailsBtn.setLayoutData (data);

        shell.pack ();
        shell.open ();

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

请帮忙解决这个问题。

Answer 1

有问题的行是这样的:

public void WidgetSelected(SelectionEvent e)

注意大写的“W”。您当前正在做的是在该匿名类中定义一个新方法(而不是覆盖现有的 widgetSelected(...) 方法)。如果您将其更改为小写“w”，如下所示，它将起作用:

public void widgetSelected(SelectionEvent e)

使用@Override注释是一个很好的实践(实际上比推荐的更好)。如果您使用了它，编译器会标记您一个错误(例如，请参阅 Joshua Bloch Effect of Java 第 2 版第 36 项:一致使用 Override 注释)