JavaFX TableColumn: is there a way to generate a column header event?

Question

I solved the basic problem I was looking at by setting a comparator on the entire table, but what I was initially trying to do was find a way to "click" the header to generate the sorting event.

I'd still like to know how to do this, as I currently do not know of a method to proc sorting methods of the columns, only the table itself.

Answer 1

Call getSortOrder() on the TableView: that returns a list of TableColumns representing the order by which rows are sorted:

An empty sortOrder list means that no sorting is being applied on the TableView. If the sortOrder list has one TableColumn within it, the TableView will be sorted using the sortType and comparator properties of this TableColumn (assuming TableColumn.sortable is true). If the sortOrder list contains multiple TableColumn instances, then the TableView is firstly sorted based on the properties of the first TableColumn. If two elements are considered equal, then the second TableColumn in the list is used to determine ordering. This repeats until the results from all TableColumn comparators are considered, if necessary.

Then just add to, remove from, set, clear, etc the list as you need.

SSCCE:

import java.util.function.Function;

import javafx.application.Application;
import javafx.beans.property.SimpleStringProperty;
import javafx.beans.property.StringProperty;
import javafx.beans.value.ObservableValue;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.ComboBox;
import javafx.scene.control.ListCell;
import javafx.scene.control.TableColumn;
import javafx.scene.control.TableView;
import javafx.scene.layout.BorderPane;
import javafx.stage.Stage;

public class TableViewProgrammaticSort extends Application {

    @Override
    public void start(Stage primaryStage) {

        TableView<Person> table = new TableView<>();

        TableColumn<Person, String> firstNameCol = column("First Name", Person::firstNameProperty);
        TableColumn<Person, String> lastNameCol = column("Last Name", Person::lastNameProperty);
        TableColumn<Person, String> emailCol = column("Email", Person::emailProperty);

        table.getColumns().add(firstNameCol);
        table.getColumns().add(lastNameCol);
        table.getColumns().add(emailCol);

        table.getItems().addAll(
            new Person("Jacob", "Smith", "jacob.smith@example.com"),
            new Person("Isabella", "Johnson", "isabella.johnson@example.com"),
            new Person("Ethan", "Williams", "ethan.williams@example.com"),
            new Person("Emma", "Jones", "emma.jones@example.com"),
            new Person("Michael", "Brown", "michael.brown@example.com")
        );

        ComboBox<TableColumn<Person, ?>> sortCombo = new ComboBox<>();
        sortCombo.getItems().add(firstNameCol);
        sortCombo.getItems().add(lastNameCol);
        sortCombo.getItems().add(emailCol);

        sortCombo.setCellFactory(lv -> new ColumnListCell());
        sortCombo.valueProperty().addListener((obs, oldColumn, newColumn) -> {
            table.getSortOrder().clear();
            if (newColumn != null) {
                table.getSortOrder().add(newColumn);
            }
        });
        sortCombo.setButtonCell(new ColumnListCell());

        BorderPane root = new BorderPane(table, sortCombo, null, null, null);
        BorderPane.setMargin(table, new Insets(10));
        BorderPane.setMargin(sortCombo, new Insets(10));
        BorderPane.setAlignment(sortCombo, Pos.CENTER);

        Scene scene = new Scene(root, 600, 600);
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    private static class ColumnListCell extends ListCell<TableColumn<Person, ?>> {
        @Override
        public void updateItem(TableColumn<Person, ?> column, boolean empty) {
            super.updateItem(column, empty);
            if (empty) {
                setText(null);
            } else {
                setText(column.getText());
            }
        }
    }

    private static <S,T> TableColumn<S,T> column(String title, Function<S, ObservableValue<T>> property) {
        TableColumn<S,T> col = new TableColumn<>(title);
        col.setCellValueFactory(cellData -> property.apply(cellData.getValue()));
        return col ;
    }

    public static class Person {
        private final StringProperty firstName = new SimpleStringProperty(this, "firstName");
        private final StringProperty lastName = new SimpleStringProperty(this, "lastName");
        private final StringProperty email = new SimpleStringProperty(this, "email");

        public Person(String firstName, String lastName, String email) {
            this.firstName.set(firstName);
            this.lastName.set(lastName);
            this.email.set(email);
        }

        public final StringProperty firstNameProperty() {
            return this.firstName;
        }

        public final java.lang.String getFirstName() {
            return this.firstNameProperty().get();
        }

        public final void setFirstName(final java.lang.String firstName) {
            this.firstNameProperty().set(firstName);
        }

        public final StringProperty lastNameProperty() {
            return this.lastName;
        }

        public final java.lang.String getLastName() {
            return this.lastNameProperty().get();
        }

        public final void setLastName(final java.lang.String lastName) {
            this.lastNameProperty().set(lastName);
        }

        public final StringProperty emailProperty() {
            return this.email;
        }

        public final java.lang.String getEmail() {
            return this.emailProperty().get();
        }

        public final void setEmail(final java.lang.String email) {
            this.emailProperty().set(email);
        }

    }

    public static void main(String[] args) {
        launch(args);
    }
}