我的应用程序中有三个域对象，如下所示：
public class Workflow {
private String name;
private List<Sheet> sheets;
}
public class Sheet {
private String name;
private List<Task> tasks;
}
public class Task {
private String name;
}
这三个都依赖于工作流程 - ＆gt;表 - ＆gt;任务。我的目标是构建TreeView，使其如下所示：
-Workflow
|
- workflow name
-Sheets
|
- sheet name
- Tasks
|
- task name
到目前为止，我已经构建了一个样本，它构建的内容比我预期的要少得多，但它不是通用的，而且是自动化的＃39;一点都不
public class TreeViewSample extends Application {
public static void main(String[] args) {
launch(args);
}
@Override
public void start(Stage primaryStage) {
primaryStage.setTitle("Tree View Sample");
Workflow w = setup();
TreeItem<String> rootItem = new TreeItem<String> ("Workflow");
rootItem.setExpanded(true);
TreeItem<String> item = new TreeItem<String> (w.getName());
rootItem.getChildren().add(item);
(...)
TreeView<String> tree = new TreeView<String> (rootItem);
StackPane root = new StackPane();
root.getChildren().add(tree);
primaryStage.setScene(new Scene(root, 300, 250));
primaryStage.show();
}
private Workflow setup(){
Workflow wflow = new Workflow();
wflow.setName("wflow name");
wflow.setSheets(Arrays.asList(new Sheet("sheet name", Arrays.asList(new Task("task name")))));
return wflow;
}
有人可以建议我如何以递归方式转到我的域对象并构建TreeView，如我的示例所示？
答案 0 :(得分：2)
您必须为所有模型（工作流，工作表，任务）创建一个公共Model，因为它们都具有String属性，创建一个非常简单。我们假设我们有以下模型：
public class Model {
private String name;
public Model(String name) {
this.name = name;
}
public String getName() {
return name;
}
@Override
public String toString() {
return getName();
}
}
class Workflow {
private String name;
private List<Sheet> sheets = new ArrayList<>();
public Workflow(String name) {
this.name = name;
}
public String getName() {
return name;
}
public List<Sheet> getSheets() {
return sheets;
}
}
class Sheet {
private String name;
private List<Task> tasks = new ArrayList<>();
public Sheet(String name) {
this.name = name;
}
public String getName() {
return name;
}
public List<Task> getTasks() {
return tasks;
}
}
class Task {
private String name;
public Task(String name) {
this.name = name;
}
public String getName() {
return name;
}
}
我把所有模型放在一起，以便更好地看待它们。
我发现您没有在您的应用中使用任何.fxml文件，我的文件是.fxml我建议您至少将Main类与Controller类分开{1}}类，如：
public class Main extends Application{
@Override
public void start(Stage primaryStage) throws Exception {
FXMLLoader loader = new FXMLLoader(getClass().getResource("View.fxml"));
AnchorPane pane = loader.load();
primaryStage.setScene(new Scene(pane,800,600));
primaryStage.show();
}
public static void main(String[] args) {
launch(args);
}
}
然后是Controller类：
public class Controller implements Initializable {
@FXML
private TreeView<Model> treeView;
@Override
public void initialize(URL location, ResourceBundle resources) {
Workflow workflow = createWorkflow(); // This just sets up the models that you are using.
// You have to create a root in your case the "Workflow"
TreeItem<Model> root = new TreeItem<>(new Model(workflow.getName()));
// The foreach sheet you create a branch
workflow.getSheets().forEach(sheet -> {
TreeItem<Model> sheetBranch = new TreeItem<>(new Model(sheet.getName()));
// Then you have to add each branch to the root
root.getChildren().add(sheetBranch);
// Then foreach sheet you create a task item
sheet.getTasks().forEach(task -> {
TreeItem<Model> taskItem = new TreeItem<>(new Model(task.getName()));
// Then you have to add each task to its sheet parent
sheetBranch.getChildren().add(taskItem);
});
});
// Finally, you set the root for the TreeView. Of course this can be done right after instantiating the root.
treeView.setRoot(root);
}
// ------------------- Setup the model -----------------------
private Workflow createWorkflow() {
Workflow workflow = new Workflow("Workflow");
workflow.getSheets().addAll(createSheets());
return workflow;
}
private List<Sheet> createSheets() {
List<Sheet> sheets = new ArrayList<>();
IntStream.range(1, 10).forEach(value -> sheets.add(createSheet()));
return sheets;
}
private Sheet createSheet() {
Sheet sheet = new Sheet("Sheet" + new Random().nextInt(100)); // Random added to have different names
sheet.getTasks().addAll(createTasks());
return sheet;
}
private List<Task> createTasks() {
List<Task> tasks = new ArrayList<>();
IntStream.range(1, 5).forEach(value -> tasks.add(createTask()));
return tasks;
}
private Task createTask() {
return new Task("Task" + new Random().nextInt(100)); // Random added to have different names
}
}
如果您需要，请查看.fxml文件：
<?xml version="1.0" encoding="UTF-8"?>
<?import javafx.scene.control.TreeView?>
<?import javafx.scene.layout.AnchorPane?>
<AnchorPane xmlns="http://javafx.com/javafx"
xmlns:fx="http://javafx.com/fxml"
fx:controller="stackoverflow.tree.Controller">
<TreeView fx:id="treeView"/>
</AnchorPane>
如果您不知道TreeView的深度，您可以使用递归创建所有分支或叶子。在这种情况下，使用两个foreach而不是创建构建树结构的递归方法要简单得多。
答案 1 :(得分：2)
缺少提供子项列表的公共超类型，您需要使用1个不同的方法/ 1个包含子对象列表的对象的嵌套循环，即
private TreeItem<String> createWorkFlow(Workflow workflow) {
TreeItem<String> item = new TreeItem<>(workflow.getName());
for (Sheet sheet : workflow.getSheets()) {
item.getChildren().add(createSheet(sheet));
}
return item;
}
private TreeItem<String> createSheet(Sheet sheet) {
TreeItem<String> item = new TreeItem<>(sheet.getName());
for (Task task : sheet.getTasks()) {
item.getChildren().add(new TreeItem<>(task.getName());
}
return item;
}
或者
private TreeItem<String> createWorkFlow(Workflow workflow) {
TreeItem<String> workflowItem = new TreeItem<>(workflow.getName());
for (Sheet sheet : workflow.getSheets()) {
TreeItem<String> sheetItem = new TreeItem<>(sheet.getName());
for (Task task : sheet.getTasks()) {
sheetItem.getChildren().add(new TreeItem<>(task.getName()));
}
workflowItem.getChildren().add(sheetItem);
}
return item;
}
除非您想使用反射。
为避免这种情况，您可以使用类型实现接口：
public interface Item<T extends Item<?>> {
String getName();
default List<T> getChildren() {
return null; // default for terminal object
}
}
这将允许您简化TreeItem到
public static <T extends Item<?>> TreeItem<String> createItem(Item<T> item) {
TreeItem<String> treeItem = new TreeItem<>(item.getName());
List<T> children = item.getChildren();
if (children != null) {
for (Item<?> ci : children) {
treeItem.getChildren().add(createItem(ci));
}
}
return treeItem;
}