JavaFX：一行填充了一个条目后的ContextMenu？ [英] JavaFX: ContextMenu after a row has been filled with an entry?

问题描述

我正在使用此链接为每个表格行创建一个ContextMenu。现在我遇到了问题因为我不确定在'type'插入行之后如何附加ContextMenu。

I am using this link for creating a ContextMenu for each table row. Right now I'm running into problems because I'm not sure how to attach a ContextMenu after the 'type' has been inserted into a row.

让我说'我使用.zip编辑器程序，它列出了内容。我有一个Image，一个文本文件和其他一些东西，所有这些东西都在一个名为 Entry 的类下面。我的表的泛型类型是'Entry'，我希望能够根据它的底层子类类型为每个条目创建一个上下文菜单（就像ImageEntry可能返回一个菜单项在图像编辑器中打开它）。 .etc）。

Lets say I'm using a .zip editor program, and it lists the contents. I have an Image, and a text file, and some other stuff, all of them are under a class called Entry. My table's generic type is 'Entry', and I'd like to be able to create a context menu for each entry based on it's underlying subclass type (like an ImageEntry might return a menu item to open it up in an image editor...etc).

现在我有一个通用的上下文菜单，但是显示一个关于用图像编辑器打开文本文件的菜单项并不是很好...

Right now I have a generic context menu for everything, but it's not great displaying a menu item about opening a text file with an image editor...

这可能吗？如果是这样，做什么的正确方法是什么？

Is this possible to do? If so, what is the proper way to go about doing it?

推荐答案

在行的 itemProperty （表示行中显示的项目）并在更改时更新上下文菜单：

Add a listener to the row's itemProperty (which represents the item displayed in the row) and update the context menu when it changes:

    table.setRowFactory(new Callback<TableView<Person>, TableRow<Person>>() {  
        @Override  
        public TableRow<Person> call(TableView<Person> tableView) {  
            final TableRow<Person> row = new TableRow<>();  
            final ContextMenu contextMenu = new ContextMenu();  

            row.itemProperty().addListener((obs, oldPerson, newPerson) -> {
                contextMenu.getItems().clear();
                // add items to context menu depending on value of newPerson
                // ...
            });

           // Set context menu on row, but use a binding to make it only show for non-empty rows:  
            row.contextMenuProperty().bind(  
                    Bindings.when(row.emptyProperty())  
                    .then((ContextMenu)null)  
                    .otherwise(contextMenu)  
            );  
            return row ;  
        }  
    });  

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