Question

我正在制作一个使用java SWT的Tree结构的程序。这是基于从外部文件和用户输入读取的数据构建的树。在这棵树上，我还附上了一个右键菜单。

主要的问题是这个树的菜单遍布他的所有项目，我希望它只在某个层面上显示。

我还希望为不同的树级别提供不同的菜单或菜单选项。

所有树的创建都在一个函数中：

public void createTree(final Composite container){
    try{
        for(Object element : container.getChildren()){
            if(element instanceof Tree){
                ((Tree) element).dispose();
            }
        }
        // function to verify if the tree is still in my container composite, and if so, I'll dispose the tree, because I am going to construct a new one

        final Tree variantTree = new Tree(container, SWT.CHECK | SWT.V_SCROLL | SWT.H_SCROLL);//creating new tree object
        variantTree.setBounds(10, 65, 400, 400);//dimensions
        //variantTree.setData("variant"); -- wanted to abuse this method to make a difference between the tree's level, 
             //but this attribute is shared across all the tree, and I cannot make a distinction between my levels

        if(..){
            //here I am using the data saved in a tree data structure to populate my SWT Tree
        }

        variantTree.addListener(SWT.Selection, new Listener(){
            //this is a listener used for the tree's checkboxes, using them to select different items from my tree
        });

        final Menu treeMenu = new Menu(variantTree);
        variantTree.setMenu(treeMenu);//adding the right click menu

        treeMenu.addMenuListener(new MenuAdapter(){
            //the menu's items are declared here: the buttons that I want to have and the their listeners
            //i am disposing the menu's items if there are any

                MenuItem newItem = new MenuItem(treeMenu, SWT.NONE);
                newItem.setText("new button...  ");
                newItem.addListener(SWT.Selection, new Listener(){

                    @Override
                    public void handleEvent(Event event) {
                            String item = variantTree.getSelection()[0].getText();//can I use this to make different menus for different tree levels?
                            for(Node element : TestControl.getTree().getChildren()){//getting the tree data structure that I have saved in a static way via a class
                                if(element.getName().equals(item)){
                            //opening a file dialog here and doing some operations
                            }
                      }
                });
        });

        //this is where I want to make the distinction between the levels of the tree, such as that I will have this menu show up only for the root of my tree, or the first level of the tree, since I will have multiple trees
        variantTree.addMenuDetectListener(new MenuDetectListener(){

            @Override
            public void menuDetected(MenuDetectEvent event) {
                // TODO Auto-generated method stub
                if(/*condition*/){ //I messed around with the tree's methods and attributes, nothing so far has come in handy to help me make a distinction between my tree's levels
                    event.doit = true;
                    //System.out.println(variantTree.getSelectionCount()); --I don't know if this can help me either, I tried to see if this will return differently for every level of the tree, but the return values is always 0
                    //find some kind of handle
                }else{
                    event.doit = false;
                }
            }

        });

另外，我想为树的第二层显示另一个菜单，我可以使用String item = variantTree.getSelection()[0].getText();，以某种方式修改以满足我的需求吗？比方说，String item = variantTree.getSelection()[1].getText();为第二级？

我的SWT树每个根的最大深度为3，它看起来像这样：

root1 - 只想要此菜单的菜单
| ---孩子 - 1级 | ------孩子 - 2级

root2 - 只需要此菜单的菜单
| ---孩子 - 1级 | -------孩子 - 2级

谢谢。

Answer 1

无需比较TotalDuration[k]+= ResReqRAM[j];个文字，只需通过以下方式检查项目的级别：检查它是否有父母。

TreeItem

这将显示级别0和1的不同菜单，而不显示级别2的菜单。

Answer 2

我已通过以下方式解决了我的问题。如果您确实看到了我的代码，则有以下几行：

for(Node element : TestControl.getTree().getChildren()){//getting the tree data structure that I have saved in a static way via a class
   if(element.getName().equals(item)){
         //opening a file dialog here and doing some operations
   }
}

我得到了我的树数据结构的第一级，然后我验证了我的SWT树的根名称是否等于树数据结构的根。

使用相同的方法，这将导致SWT Tree的菜单监听器结束：

variantTree.addMenuDetectListener(new MenuDetectListener(){

            @Override
            public void menuDetected(MenuDetectEvent event) {
                // TODO Auto-generated method stub
                for(Node element : TestControl.getTree().getChildren()){
                    if(variantTree.getSelection()[0].getText().equals(element.getName())){
                        event.doit = true;
                        break;//need this, because it will propagate only to the last item, or it will have a strange behaviour
                    }else{
                        event.doit = false;
                    }
                }
            }

        });

其中element是来自我的树数据结构的节点。希望它可以帮助任何有同样问题的人。

Java SWT树菜单仅显示树的一个级别

2 个答案: