JavaFX：TreeTableView和展开没有子项的项目

JavaFX：TreeTableView和展开没有子项的项目

的Javadocs

TreeItem

显示了一个基本上执行此 *** 作的示例。您可以重写

isLeaf

和

getChildren

方法以延迟实例化子级。这是适用于的相同想法

TreeTableView

：

import java.util.ArrayList;import java.util.Arrays;import java.util.List;import javafx.application.Application;import javafx.beans.property.IntegerProperty;import javafx.beans.property.SimpleIntegerProperty;import javafx.beans.property.SimpleStringProperty;import javafx.beans.property.StringProperty;import javafx.collections.ObservableList;import javafx.event.Event;import javafx.scene.Scene;import javafx.scene.control.TreeItem;import javafx.scene.control.TreeTableColumn;import javafx.scene.control.TreeTableView;import javafx.scene.layout.BorderPane;import javafx.stage.Stage;public class LazyTreeTable extends Application {    @Override    public void start(Stage primaryStage) {        TreeTableView<Item> treeTable = new TreeTableView<>();        TreeTableColumn<Item, String> nameCol = new TreeTableColumn<>("Name");        nameCol.setCellValueFactory(cellData -> cellData.getValue().getValue().nameProperty());        nameCol.setPrefWidth(250);        TreeTableColumn<Item, Number> valueCol = new TreeTableColumn<>("Value");        valueCol.setCellValueFactory(cellData -> cellData.getValue().getValue().valueProperty());        valueCol.setPrefWidth(150);        treeTable.getColumns().addAll(Arrays.asList(nameCol, valueCol));        treeTable.setRoot(new ItemTreeNode(new Item(1)));        primaryStage.setScene(new Scene(new BorderPane(treeTable), 400, 600));        primaryStage.show();    }    public static class ItemTreeNode extends TreeItem<Item> {        private boolean childrenLoaded = false ;        public ItemTreeNode(Item value) { super(value);        }        @Override        public boolean isLeaf() { if (childrenLoaded) {     return getChildren().isEmpty() ; } return false ;//          return getChildren().isEmpty();        }        @Override        public ObservableList<TreeItem<Item>> getChildren() { if (childrenLoaded) {     return super.getChildren(); } childrenLoaded = true ; if (getValue().getValue() < 100_000) {     List<TreeItem<Item>> children = new ArrayList<>();     for (int i = 0 ; i < 10; i++) {         children.add(new ItemTreeNode(new Item(getValue().getValue() * 10 + i)));     }     super.getChildren().addAll(children); } else {     // great big hack:     super.getChildren().add(null);     super.getChildren().clear(); } return super.getChildren() ;        }    }    public static class Item {        private IntegerProperty value = new SimpleIntegerProperty();        private StringProperty name = new SimpleStringProperty();        public Item(String name, int value) { setName(name); setValue(value);        }        public Item(int value) { this(String.format("Item %,d", value), value);        }        public final IntegerProperty valueProperty() { return this.value;        }        public final int getValue() { return this.valueProperty().get();        }        public final void setValue(final int value) { this.valueProperty().set(value);        }        public final StringProperty nameProperty() { return this.name;        }        public final java.lang.String getName() { return this.nameProperty().get();        }        public final void setName(final java.lang.String name) { this.nameProperty().set(name);        }    }    public static void main(String[] args) {        launch(args);    }}