Modifying the selection behavior in any controls in JavaFX seems to be a bit of a pain; but the "proper" way to do this is to define a custom selection model for the tree. The easiest way to do this is to wrap the default selection model, and delegate the method calls to it, vetoing selection if the selection index is for an item which shouldn't be selected.
It's a good idea to select something whenever possible when a select method is called, as otherwise keyboard navigation will break.
Here is an implementation:
import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.IntStream;
import java.util.stream.Stream;
import javafx.application.Application;
import javafx.collections.ObservableList;
import javafx.scene.Scene;
import javafx.scene.control.MultipleSelectionModel;
import javafx.scene.control.SelectionMode;
import javafx.scene.control.TreeItem;
import javafx.scene.control.TreeView;
import javafx.scene.layout.BorderPane;
import javafx.stage.Stage;
public class CustomTreeSelectionModelExample extends Application {
@Override
public void start(Stage primaryStage) {
TreeItem<Object> root = new TreeItem<>("Root");
for (int i = 1 ; i <= 5 ; i++) {
TreeItem<Object> item = new TreeItem<>(new Tour("Tour "+i));
for (int j = 1 ; j <= 5; j++) {
Delivery delivery = new Delivery("Delivery "+j);
item.getChildren().add(new TreeItem<>(delivery));
}
root.getChildren().add(item);
}
TreeView<Object> tree = new TreeView<>();
tree.setSelectionModel(new TourSelectionModel(tree.getSelectionModel(), tree));
tree.setRoot(root);
primaryStage.setScene(new Scene(new BorderPane(tree), 400, 400));
primaryStage.show();
}
public static class TourSelectionModel extends MultipleSelectionModel<TreeItem<Object>> {
private final MultipleSelectionModel<TreeItem<Object>> selectionModel ;
private final TreeView<Object> tree ;
public TourSelectionModel(MultipleSelectionModel<TreeItem<Object>> selectionModel, TreeView<Object> tree) {
this.selectionModel = selectionModel ;
this.tree = tree ;
selectionModeProperty().bindBidirectional(selectionModel.selectionModeProperty());
}
@Override
public ObservableList<Integer> getSelectedIndices() {
return selectionModel.getSelectedIndices() ;
}
@Override
public ObservableList<TreeItem<Object>> getSelectedItems() {
return selectionModel.getSelectedItems() ;
}
@Override
public void selectIndices(int index, int... indices) {
List<Integer> indicesToSelect = Stream.concat(Stream.of(index), IntStream.of(indices).boxed())
.filter(i -> tree.getTreeItem(i).getValue() instanceof Tour)
.collect(Collectors.toList());
if (indicesToSelect.isEmpty()) {
return ;
}
selectionModel.selectIndices(indicesToSelect.get(0),
indicesToSelect.stream().skip(1).mapToInt(Integer::intValue).toArray());
}
@Override
public void selectAll() {
List<Integer> indicesToSelect = IntStream.range(0, tree.getExpandedItemCount())
.filter(i -> tree.getTreeItem(i).getValue() instanceof Tour)
.boxed()
.collect(Collectors.toList());
if (indicesToSelect.isEmpty()) {
return ;
}
selectionModel.selectIndices(0,
indicesToSelect.stream().skip(1).mapToInt(Integer::intValue).toArray());
}
@Override
public void selectFirst() {
IntStream.range(0, tree.getExpandedItemCount())
.filter(i -> tree.getTreeItem(i).getValue() instanceof Tour)
.findFirst()
.ifPresent(selectionModel::select);
}
@Override
public void selectLast() {
IntStream.iterate(tree.getExpandedItemCount() - 1, i -> i - 1)
.limit(tree.getExpandedItemCount())
.filter(i -> tree.getTreeItem(i).getValue() instanceof Tour)
.findFirst()
.ifPresent(selectionModel::select);
}
@Override
public void clearAndSelect(int index) {
int toSelect = index ;
int direction = selectionModel.getSelectedIndex() < index ? 1 : -1 ;
while (toSelect >= 0 && toSelect < tree.getExpandedItemCount() && ! (tree.getTreeItem(toSelect).getValue() instanceof Tour)) {
toSelect = toSelect + direction ;
}
if (toSelect >= 0 && toSelect < tree.getExpandedItemCount()) {
selectionModel.clearAndSelect(toSelect);
}
}
@Override
public void select(int index) {
int toSelect = index ;
int direction = selectionModel.getSelectedIndex() < index ? 1 : -1 ;
while (toSelect >= 0 && toSelect < tree.getExpandedItemCount() && ! (tree.getTreeItem(toSelect).getValue() instanceof Tour)) {
toSelect = toSelect + direction ;
}
if (toSelect >= 0 && toSelect < tree.getExpandedItemCount()) {
selectionModel.select(toSelect);
}
}
@Override
public void select(TreeItem<Object> obj) {
if (obj.getValue() instanceof Tour) {
selectionModel.select(obj);
}
}
@Override
public void clearSelection(int index) {
selectionModel.clearSelection(index);
}
@Override
public void clearSelection() {
selectionModel.clearSelection();
}
@Override
public boolean isSelected(int index) {
return selectionModel.isSelected(index);
}
@Override
public boolean isEmpty() {
return selectionModel.isEmpty();
}
@Override
public void selectPrevious() {
int current = selectionModel.getSelectedIndex() ;
if (current > 0) {
IntStream.iterate(current - 1, i -> i - 1).limit(current)
.filter(i -> tree.getTreeItem(i).getValue() instanceof Tour)
.findFirst()
.ifPresent(selectionModel::select);
}
}
@Override
public void selectNext() {
int current = selectionModel.getSelectedIndex() ;
if (current < tree.getExpandedItemCount() - 1) {
IntStream.range(current + 1, tree.getExpandedItemCount())
.filter(i -> tree.getTreeItem(i).getValue() instanceof Tour)
.findFirst()
.ifPresent(selectionModel::select);
}
}
}
public static class Tour {
private final String name ;
public Tour(String name) {
this.name = name ;
}
public String getName() {
return name ;
}
@Override
public String toString() {
return getName();
}
}
public static class Delivery {
private final String name;
public Delivery(String name) {
this.name = name;
}
public String getName() {
return name;
}
@Override
public String toString() {
return getName();
}
}
public static void main(String[] args) {
launch(args);
}
}
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