在 Vaadin 8.1 TreeGrid 中替换 collapseItemsRecursively 和 expandItemsRecursively

Question

Vaadin 8.1 引入了 TreeGrid 组件。它不再有 collapseItemsRecursively 和 expandItemsRecursively 方法（在现在的遗留 Tree 组件中可用）。我错过了什么或者你需要开发自己的实现吗？如果是这样，推荐的方法是什么？

Answer 1

来自 docs for treegrid, you can use the methods, collapse and expand，通过传递树状网格数据项的列表或数组来展开或折叠：

treeGrid.expand(someTreeGridItem1, someTreeGridItem2);
treeGrid.collapse(someTreeGridItem1);

同样值得注意的是，显示 prevent certain items from ever being collapsed

能力的部分

Answer 2

我相信您已经注意到，TreeGrid 是一个相当新的组件，目前正在开发中，从 v8 开始可用。1.alphaX（当前的稳定版本是 v8.0.6）。因此，它目前可能只有一些基本功能，其余的将在未来的某个时候推出，尽管不能保证。例如 this similar feature request for the older TreeTable component 自 2011 年以来一直处于开放状态。

无论哪种方式，即使它们可能不是最佳解决方案，您也可以使用一些解决方法来实现此行为。我 无耻地 将 vaadin-sampler for TreeGrid.

当前可用代码的略微修改版本用作基本示例

public class RecursiveExpansionTreeGrid extends VerticalLayout {

    private Random random = new Random();

    public RecursiveExpansionTreeGrid() {
        // common setup with some dummy data
        TreeGrid<Project> treeGrid = new TreeGrid<>();
        treeGrid.setItems(generateProjectsForYears(2010, 2016), Project::getSubProjects);
        treeGrid.addColumn(Project::getName).setCaption("Project Name").setId("name-column");
        treeGrid.addColumn(Project::getHoursDone).setCaption("Hours Done");
        treeGrid.addColumn(Project::getLastModified).setCaption("Last Modified");
        addComponent(treeGrid);
    }

    // generate some dummy data to display in the tree grid
    private List<Project> generateProjectsForYears(int startYear, int endYear) {
        List<Project> projects = new ArrayList<>();

        for (int year = startYear; year <= endYear; year++) {
            Project yearProject = new Project("Year " + year);

            for (int i = 1; i < 2 + random.nextInt(5); i++) {
                Project customerProject = new Project("Customer Project " + i);
                customerProject.setSubProjects(Arrays.asList(
                        new LeafProject("Implementation", random.nextInt(100), year),
                        new LeafProject("Planning", random.nextInt(10), year),
                        new LeafProject("Prototyping", random.nextInt(20), year)));
                yearProject.addSubProject(customerProject);
            }
            projects.add(yearProject);
        }
        return projects;
    }

    // POJO for easy binding
    public class Project {
        private List<Project> subProjects = new ArrayList<>();
        private String name;

        public Project(String name) {
            this.name = name;
        }

        public String getName() {
            return name;
        }

        public List<Project> getSubProjects() {
            return subProjects;
        }

        public void setSubProjects(List<Project> subProjects) {
            this.subProjects = subProjects;
        }

        public void addSubProject(Project subProject) {
            subProjects.add(subProject);
        }

        public int getHoursDone() {
            return getSubProjects().stream().map(project -> project.getHoursDone()).reduce(0, Integer::sum);
        }

        public Date getLastModified() {
            return getSubProjects().stream().map(project -> project.getLastModified()).max(Date::compareTo).orElse(null);
        }
    }

    // Second POJO for easy binding
    public class LeafProject extends Project {
        private int hoursDone;
        private Date lastModified;

        public LeafProject(String name, int hoursDone, int year) {
            super(name);
            this.hoursDone = hoursDone;
            lastModified = new Date(year - 1900, random.nextInt(12), random.nextInt(10));
        }

        @Override
        public int getHoursDone() {
            return hoursDone;
        }

        @Override
        public Date getLastModified() {
            return lastModified;
        }
    }
}

接下来，递归展开或折叠节点有点取决于您的场景，但基本上它分解为同一件事：确保从根到最深叶的每个节点都是 expanded/collapsed。最简单的这样做的方法是 将您的层次结构展平 到节点列表中，然后调用适当的方法 expand(List<T> items) 或 expand(T ... items) （第二个代表第一个和可能是一种方便的方法，例如 expand(myItem)).

为简单起见，我在 Project 实现中添加了一个 flatten 方法。如果由于某种原因您不能这样做，则创建一个递归方法，该方法创建一个列表，该列表从所选节点开始并包括所有子节点，子节点的，子节点的……好吧，您明白了。

public Stream<Project> flatten() {
    return Stream.concat(Stream.of(this), getSubProjects().stream().flatMap(Project::flatten));
}

可能的场景：

展开根时自动展开整个层级 - 添加监听器，expand/collapse整个展平层级：

treeGrid.addCollapseListener(event -> {
    if (event.isUserOriginated()) {
        // event is triggered by all collapse calls, so only do it the first time, when the user clicks in the UI
        // and ignore the programmatic calls
        treeGrid.collapse(event.getCollapsedItem().flatten().collect(Collectors.toList()));
    }
});
treeGrid.addExpandListener(event -> {
    if (event.isUserOriginated()) {
        // event is triggered by all expand calls, so only do it the first time, when the user clicks in the UI
        // and ignore the programmatic calls
        treeGrid.expand(event.getExpandedItem().flatten().collect(Collectors.toList()));
    }
});

使用上下文菜单等自定义操作扩展层次结构或其中的一部分

GridContextMenu<Project> contextMenu = new GridContextMenu<>(treeGrid);
contextMenu.addGridBodyContextMenuListener(contextEvent -> {
    contextMenu.removeItems();
    if (contextEvent.getItem() != null) {
        Project project = (Project) contextEvent.getItem();
        // update selection
        treeGrid.select(project);

        // show option for expanding
        contextMenu.addItem("Expand all", VaadinIcons.PLUS, event -> treeGrid.expand((project).flatten().collect(Collectors.toList())));

        // show option for collapsing
        contextMenu.addItem("Collapse all", VaadinIcons.MINUS, event -> treeGrid.collapse((project).flatten().collect(Collectors.toList())));
    }
});

最后你应该得到这样的效果：

在 Vaadin 8.1 TreeGrid 中替换 collapseItemsRecursively 和 expandItemsRecursively

Replacement for collapseItemsRecursively and expandItemsRecursively in Vaadin 8.1 TreeGrid

vaadin

vaadin8