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);
                }
            }
        }
    }
}