象其它的layout类一样，FormLayout用的data类是:FormData。FormData用另外一个类来控制窗口小部件的大小和位置: FormAttachment.一个FormData最多用4个FormAttachment,它们分别对应这个小部件的4个面:顶部，底部，左边和右边。FormAttachment定义了小部件在parent composite或是这个composite里其它部

FormLayout layout= new FormLayout("5dlu,40dlu:grow,5dlu,20dlu:grow,5dlu,100dlu:grow,5dlu"                                              ,"min"); layout.setColumnGroups(new int[][]{{2, 4}});  //分组