java - 将 RadioGroupFieldEditor 放置在 FormLayout 中时出现 ClassCastException

Question

我是 SWT GUI 开发的新手。我正在使用 SWT 开发 Eclipse 插件。基本上，我想要两个单选选项组和第二个单选选项组下方的一些文本框；像下面这样。

    Heading1
    . A radio button
    . B radio button
    Heading2
    . C radio button
    . D radio button
    Textbox1 Textbox2 Textbox3

由于我需要这些文本框相互关联，所以我使用了 FormLayout。但这给了我异常(exception):

Caused by: java.lang.ClassCastException: org.eclipse.swt.layout.FormData cannot be cast to org.eclipse.swt.layout.GridData*

但我没有使用过GridData。第 129 行发生异常。我无法相对于 Textbox1 添加 Textbox2。我的代码如下。

        Shell sh = new Shell(parent_shell,SWT.PRIMARY_MODAL | SWT.TRAIL | SWT.CASCADE);
        System.out.println("execute");
        FormLayout fL = new FormLayout();
        sh.setLayout(fL);
        sh.setText("Configure");

        sh.setSize(330,300);
        sh.setActive();

        Composite composite = new Composite( sh, SWT.NONE );
         GridLayout layout = new GridLayout();
         layout.marginWidth = 0;
         layout.marginHeight = 0;
         composite.setLayout( layout );

         FormData fd = new FormData(); //line 100
         fd.top = new FormAttachment(0,0);//line 101
         fd.left = new FormAttachment(0,0);//line 102
         //fd.right = new FormAttachment(26);//line 103
         //fd.bottom = new FormAttachment(10);//line 104
         composite.setLayoutData( fd );

         RadioGroupFieldEditor rgfe = new RadioGroupFieldEditor("User Choice",
                 "Heading1", 1, new String[][]{
             {"A radio button","a"},{"B radio button","b"}
         }, composite,false);

         RadioGroupFieldEditor rgfe1 = new RadioGroupFieldEditor("User Choice1",
                 "Heading2", 1, new String[][]{
             {"C radio button","c"},{"D radio button","d"}
         }, composite,false);



         Text ol = new Text(composite,SWT.READ_ONLY);
            ol.setText("Output Location");
            ol.setEnabled(false);

//              FormData fd1 = new FormData();
//              fd.top = new FormAttachment(fd);
//              fd.left = new FormAttachment(1);
//              fd.right = new FormAttachment(26);
//              fd.bottom = new FormAttachment(10);
//              ol.pack();
//              ol.setLayoutData(fd1); //line 129 --> exception occurs




         while (!sh.isDisposed()) {
              if (!parent_display.readAndDispatch()) {
                  parent_display.sleep();
              }
            }

    }

Answer 1

RadioGroupFieldEditor 假定其父级设置了 GridLayout。

我建议您将 RadioGroupFieldEditor 嵌入到具有 GridLayout 集的单独 Composite 中。然后您可以将 FormData 附加到 Composite 来控制其布局。

例如:

Composite composite = new Composite( sh, SWT.NONE );
GridLayout layout = new GridLayout();
layout.marginWidth = 0;
layout.marginHeight = 0;
composite.setLayout( layout );
FormData compositeFormData = new FormData();
...
composite.setLayoutData( compositeFormData );
RadioGroupFieldEditor fieldEditor = new RadioGroupFieldEditor( ..., composite, ... );