JavaFX TableView scrollTo() causing wrong row to s

问题:

I have an editable TableView with a button that adds a new row then calls table.edit() on the first column in that row. When a user wants to add a row that will be out of the viewport, what should happen is the table scrolls the new row within the viewport and starts editing. However, calling table.scrollTo(newRow) causes all sorts of buggy behavior. The row is brought into view, but only some of the time goes into editing. What seems to happen the most is the first row within the viewport starts editing rather than the newly added row. This happens on rows that would be added in view as well as rows that would be out of view.

My code:

import javafx.application.Application;
import javafx.application.Platform;
import javafx.beans.property.SimpleStringProperty;
import javafx.beans.property.StringProperty;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.geometry.Insets;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.TableColumn;
import javafx.scene.control.TableColumn.CellEditEvent;
import javafx.scene.control.TableView;
import javafx.scene.control.cell.PropertyValueFactory;
import javafx.scene.control.cell.TextFieldTableCell;
import javafx.scene.layout.HBox;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;


public class TableViewScrollToTest extends Application {

    private final TableView<Person> table = new TableView<>();
    private final ObservableList<Person> data = FXCollections.observableArrayList();
    private final HBox hb = new HBox();
    private final Button addButton = new Button("_Add");
    private int seq = 0;

    @Override
    public void start(Stage primaryStage) throws Exception {
        Scene scene = new Scene(new Group());
        primaryStage.setTitle("Table View Scroll To Test");
        primaryStage.setWidth(450);
        primaryStage.setHeight(300);

        table.setEditable(true);

        TableColumn<Person, String> firstNameCol = new TableColumn<>("First Name");
        firstNameCol.setMinWidth(100);
        firstNameCol.setCellValueFactory(new PropertyValueFactory<Person, String>("firstName"));
        firstNameCol.setCellFactory(TextFieldTableCell.<Person> forTableColumn());
        firstNameCol.setOnEditCommit((CellEditEvent<Person, String> event) -> {
            event.getRowValue().setFirstName(event.getNewValue());
        });

        TableColumn<Person, String> lastNameCol = new TableColumn<>("Last Name");
        lastNameCol.setMinWidth(100);
        lastNameCol.setCellValueFactory(new PropertyValueFactory<Person, String>("lastName"));
        lastNameCol.setCellFactory(TextFieldTableCell.<Person> forTableColumn());
        lastNameCol.setOnEditCommit((CellEditEvent<Person, String> event) -> {
            event.getRowValue().setLastName(event.getNewValue());
        });

        TableColumn<Person, String> emailCol = new TableColumn<>("Email");
        emailCol.setMinWidth(200);
        emailCol.setCellValueFactory(new PropertyValueFactory<Person, String>("email"));
        emailCol.setCellFactory(TextFieldTableCell.<Person> forTableColumn());
        emailCol.setOnEditCommit((CellEditEvent<Person, String> event) -> {
            event.getRowValue().setEmail(event.getNewValue());
        });

        table.setItems(data);
        table.getColumns().addAll(firstNameCol, lastNameCol, emailCol);
        table.setPrefHeight(165);

        addButton.setOnAction(event -> {
            table.getSelectionModel().clearSelection();
            Person p = new Person("First Name", "Last Name " + seq++, "");
            data.add(p);
            table.getSelectionModel().select(p);
            Platform.runLater(() -> {
                table.scrollTo(p); //causes buggy behavior
                table.edit(data.indexOf(p), firstNameCol);
            });
        });

        hb.getChildren().add(addButton);

        final VBox vbox = new VBox();
        vbox.setSpacing(5);
        vbox.setPadding(new Insets(10, 0, 0, 10));
        vbox.getChildren().addAll(table, hb);

        ((Group)scene.getRoot()).getChildren().addAll(vbox);

        primaryStage.setScene(scene);
        primaryStage.show();
    }

    public static class Person {

        private StringProperty firstName;
        private StringProperty lastName;
        private StringProperty email;

        public Person(String first, String last, String email) {
            firstName = new SimpleStringProperty(this, "firstName", first);
            lastName = new SimpleStringProperty(this, "lastName", last);
            this.email = new SimpleStringProperty(this, "email", email);
        }

        public void setFirstName(String value) { firstNameProperty().set(value); }
        public String getFirstName() { return firstNameProperty().get(); }
        public StringProperty firstNameProperty() { 
            if (firstName == null) firstName = new SimpleStringProperty(this, "firstName", "First");
            return firstName; 
        }

        public void setLastName(String value) { lastNameProperty().set(value); }
        public String getLastName() { return lastNameProperty().get(); }
        public StringProperty lastNameProperty() { 
            if (lastName == null) lastName = new SimpleStringProperty(this, "lastName", "Last");
            return lastName; 
        } 

        public void setEmail(String value) { emailProperty().set(value); }
        public String getEmail() { return emailProperty().get(); }
        public StringProperty emailProperty() {
            if(email == null) {
                email = new SimpleStringProperty(this, "email", "");
            }
            return email;
        }
    }

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

If you comment out the table.scrollTo(), adding then editing the row works fine. I tried https://stackoverflow.com/a/27786741/3050379 but isIndexVisible() returns false at times even when the row being added is in view. I've tried every combination of the order of method calls and runnables that I could think of with the same result. If anyone could help me out, I would really appreciate it.

回答1:

Completely random hack that seems to work, despite me having no explanation for it:

    table.scrollTo(p); 
    table.layout();
    table.edit(data.indexOf(p), firstNameCol);

You don't need the Platform.runLater(...) with this. I would file a bug for this, though, as the random hack should not be necessary...

This was inspired by Uluk Biy's answer to this question