关于JFace带复选框的树

树的复选框用CheckboxTreeViewer实现.由于其子类ContainerCheckedTreeViewer在没有选择全部子节点时可以自动将父节点设置成灰选,所以实现树的复选框更多的是用ContainerCheckedTreeViewer.

关于这个ContainerCheckedTreeViewer类我没有在SWT/JFace的API文档中找到,但是在Eclipse中查看源码能找到.

CheckboxTreeViewer的继承类关系图:

TreeView4.java

 public class TreeViewer4 {
     public static void main(String[] args) {
         new TreeViewer4().open();
     }

     public void open() {
         final Display display = new Display();
         final Shell shell = new Shell();
         shell.setSize(300, 300);
         // -----------界面核心代码-------------------
         shell.setLayout(new FillLayout());
         // 用ContainerCheckedTreeViewer完全替换TreeViewer
         ContainerCheckedTreeViewer tv = new ContainerCheckedTreeViewer(shell, SWT.BORDER);
         tv.setUseHashlookup(true); // 加快查找速度

         Tree tree = tv.getTree();
         tree.setHeaderVisible(true);
         TreeColumn column = new TreeColumn(tree, SWT.LEFT);
         column.setText("名称");
         column.setWidth(150);
         column = new TreeColumn(tree, SWT.LEFT);
         column.setText("子结点数");
         column.setWidth(80);
         column = new TreeColumn(tree, SWT.LEFT);
         column.setText("性别");
         column.setWidth(40);

         tv.setContentProvider(new TreeViewerContentProvider());//设置"内容器"
         tv.setLabelProvider(new MyTableLableProvider());//设置"标签器"
         // 和TableViewer一样，数据的入口也是setInput方法
         List<Country> input = (List)DataFactory.createTreeData();
32         tv.setInput(input);
         MyActionGroup2 actionGroup = new MyActionGroup2(tv);// 改用另一个ActionGroup
         actionGroup.fillContextMenu(new MenuManager());// 将按钮注入到菜单对象中
         // -----------END------------------
         shell.open();
         while (!shell.isDisposed()) {
             if (!display.readAndDispatch())
                 display.sleep();
         }
         display.dispose();
     }
 }

MyActionGroup2.java

 public class MyActionGroup2 extends ActionGroup {
     private ContainerCheckedTreeViewer tv;

     public MyActionGroup2(ContainerCheckedTreeViewer tv) {
         this.tv = tv;
     }
 //这个地方直译方法名就是"填充上下文菜单fillContextMenu()传入的是一个菜单管理器的类(接口)"
     public void fillContextMenu(IMenuManager mgr) {
         MenuManager menuManager = (MenuManager) mgr;
         menuManager.add(new SelectAllAction());//通过菜单管理器增加一个"全选"的Action()
         menuManager.add(new RemoveEntryAction());//通过菜单管理器增加一个"删除"的Action()
         Tree tree = tv.getTree();//getTree()是TreeViewer类下的一个方法. 就是返回这个视图的树形结构.
         Menu menu = menuManager.createContextMenu(tree);
         tree.setMenu(menu);
     }

     private class SelectAllAction extends Action {//首先继承Action接口
         public SelectAllAction() {//首先就是重写这个Action对应的构造方法
             setText("勾选当前结点的所有子结点");
         }

         public void run() {//每个Action中都有对应的run()方法.
             IStructuredSelection selection = (IStructuredSelection) tv.getSelection();
             ITreeEntry entry = (ITreeEntry) (selection.getFirstElement());
             tv.setSubtreeChecked(entry, true); // false不勾选
         }
     }

     // 删除结点的Action类
     private class RemoveEntryAction extends Action {
         public RemoveEntryAction() {
             setText("删除");
         }

         public void run() {
             Object[] checks = tv.getCheckedElements();// 取得被勾选的结点（包括灰选）
             if (checks.length == 0) {
                 MessageDialog.openInformation(null, "提示", "请先勾选记录");
                 return;
             }
             List<ITreeEntry> inputList = (List<ITreeEntry>) tv.getInput();
             for (Object object : checks) {
                 if (tv.getGrayed(object))
                     continue;// 灰选结点不删除
                 ITreeEntry entry = (ITreeEntry) object;
                 remove(inputList, entry);
                 tv.remove(entry);
             }
         }

         private void remove(List<ITreeEntry> list, ITreeEntry entry) {
             if (list == null)
                 return;
             for (Iterator it = list.iterator(); it.hasNext();) {
                 ITreeEntry o = (ITreeEntry) it.next();
                 if (o.getName().equals(entry.getName())) {
                     it.remove();
                     return;
                 } else {
                     remove(o.getChildren(), entry);
                 }
             }
         }
     }
 }