我需要根据列过滤树网格。我已遵循此问题中所述的解决方案。我已经尝试使用下面的代码片段进行过滤，但是它不显示任何数据。
TreeDataProvider<Project> dataProvider = new TreeDataProvider<>(treeGrid.getTreeData());
dataProvider.setFilter(Project -> (Project.getStatus() != null && Project.getStatus().equals(Project.Status.PASS)));
treeGrid.setDataProvider(dataProvider);
treeGrid.getDataProvider().refreshAll();
是否有另一种方法可以使用 vaadin 8.1 树网格过滤数据。
你的问题很可能
dataProvider.setFilter(Project -> (Project.getStatus() != null && Project.getStatus().equals(Project.Status.PASS)));
我假设您的根节点和中间节点的状态为空，因此它们与过滤器不匹配，因此不会显示它们的子节点。
为简单起见，您可以允许状态为 null 或匹配过滤器的项目，但有时您可能会得到空的中间节点，因为没有子节点会匹配过滤器：
dataProvider.setFilter(Project -> (Project.getStatus() == null || Project.getStatus().equals(Project.Status.PASS)));
防弹解决方案有点棘手，因为您需要允许在层次结构中至少有一个与过滤器匹配的子节点。这可能是矫枉过正，但这是我能想到的在内存数据中使用的最快方法，所以任何有改进建议的人，请分享。如果数据是从数据库查询中过滤出来的，你可能不需要这个。
无论如何，我已经添加了一个flatten方法Project，显然，它将项目层次结构扁平化为一个项目流，您可以快速遍历并查看它们中的任何一个是否与您的过滤器匹配。Bellow 是完整的实现，基于您链接的另一个问题。我还更改了最初将数据输入树形网格的方式，因此您不必像new TreeDataProvider<>(treeGrid.getTreeData());
import com.vaadin.data.TreeData;
import com.vaadin.data.provider.TreeDataProvider;
import com.vaadin.ui.ComboBox;
import com.vaadin.ui.Notification;
import com.vaadin.ui.TreeGrid;
import com.vaadin.ui.VerticalLayout;
import java.util.*;
import java.util.stream.Stream;
public class BasicTreeGrid extends VerticalLayout {
// used to generate some random data
private final Random random = new Random();
public BasicTreeGrid() {
// basic setup
setSizeFull();
TreeGrid<Project> treeGrid = new TreeGrid<>();
treeGrid.setSizeFull();
addComponent(treeGrid);
treeGrid.addColumn(Project::getName).setCaption("Project Name").setId("name-column");
treeGrid.addColumn(Project::getHoursDone).setCaption("Hours Done").setId("hour-column");
treeGrid.addColumn(Project::getLastModified).setCaption("Last Modified").setId("date-column");
treeGrid.addColumn(Project::getStatus).setCaption("Status").setId("status-column");
// some listeners for interaction
treeGrid.addCollapseListener(event -> Notification
.show("Project '" + event.getCollapsedItem().getName() + "' collapsed.", Notification.Type.TRAY_NOTIFICATION));
treeGrid.addExpandListener(event -> Notification
.show("Project '" + event.getExpandedItem().getName() + "' expanded.", Notification.Type.TRAY_NOTIFICATION));
// add the list of root projects and specify a provider of sub-projects
TreeData<Project> data = new TreeData<>();
data.addItems(generateProjectsForYears(2010, 2016), Project::getSubProjects);
TreeDataProvider<Project> dataProvider = new TreeDataProvider<>(data);
treeGrid.setDataProvider(dataProvider);
// filter combo setup
ComboBox<Status> statusFilter = new ComboBox<>();
statusFilter.setItems(Status.values());
statusFilter.setEmptySelectionCaption("ALL");
statusFilter.addValueChangeListener(event -> {
if (event.getValue() == null) {
dataProvider.clearFilters();
} else {
dataProvider.setFilter(project -> {
if (project.getSubProjects() == null | project.getSubProjects().isEmpty()) {
// include final nodes matching the filter
return project.getStatus() == null || project.getStatus() == event.getValue();
} else {
// include root and intermediate nodes that have children matching the filter
return project.flatten().anyMatch(subProject -> subProject.getStatus() == event.getValue());
}
});
}
});
// add filter combo to header
treeGrid.appendHeaderRow().getCell("status-column").setComponent(statusFilter);
}
// generate some random projects
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, Status.values()[random.nextInt(3)]),
new LeafProject("Planning", random.nextInt(10), year, Status.values()[random.nextInt(3)]),
new LeafProject("Prototyping", random.nextInt(20), year, Status.values()[random.nextInt(3)])));
yearProject.addSubProject(customerProject);
}
projects.add(yearProject);
}
return projects;
}
// project status
enum Status {
NOT_STARTED, IN_PROGRESS, DONE
}
// basic parent (or intermediate child) bean used for easy binding
class Project {
private List<Project> subProjects = new ArrayList<>();
private String name;
private Status status;
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);
}
public Status getStatus() {
return status;
}
public void setStatus(Status status) {
this.status = status;
}
// flatten the project hierarchy into a stream of items
public Stream<Project> flatten() {
return Stream.concat(
Stream.of(this),
subProjects.stream().flatMap(Project::flatten));
}
}
// basic final child (can not have other children) bean used for easy binding
class LeafProject extends Project {
private int hoursDone;
private Date lastModified;
public LeafProject(String name, int hoursDone, int year, Status status) {
super(name);
setStatus(status);
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;
}
}
}
结果：
