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JavaFX 11 uneditable ComboBox not displaying values outside combo items list properly

I have troubles with JaxaFX 11 ComboBox (it seems that in JavaFX 8 it works OK).
For uneditable combo, i.e. displaying the selected value in buttoncell (not in editable textbox), no value is displayed (buttoncell probably considered "empty"), if the new value is not included in the combo's items list, with one exception only:
If the previous value is null (I e.g. deselect the previous non null value by keyboard in popup list), the new non null value is displayed correctly.
See a simple code to reproduce the problem. Initially, the combo value is null. Press the button to set a value outside items list. It is displayed OK. Then choose some value from the popup. Try again to press the button. Now the combo stays empty, although the combo value was changed.
import javafx.application.Application;
import static javafx.application.Application.launch;
import javafx.collections.FXCollections;
import javafx.geometry.Insets;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.ComboBox;
import javafx.scene.control.TextField;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;
public class ComboTest extends Application {
private ComboBox<String> testCombo;
#Override public void start(Stage primaryStage) {
Button btn = new Button("Set test value outside list");
btn.setOnAction(e -> {
testCombo.setValue("test value outside list");
});
testCombo = new ComboBox<>(FXCollections.observableArrayList(
"Option 1", "Option 2", "Option 3"
));
testCombo.setPromptText("null now!");
TextField valueTextField = new TextField();
testCombo.valueProperty().addListener((ob, ov, nv) -> {
valueTextField.setText("combo value: " + nv);
});
VBox root = new VBox(5);
root.setPadding(new Insets(5));
root.getChildren().addAll(btn, testCombo, valueTextField);
Scene scene = new Scene(root, 300, 250);
primaryStage.setTitle("Test Combo");
primaryStage.setScene(scene);
primaryStage.show();
}
public static void main(String[] args) {
launch(args);
}
}
Am I missing something? I was not able to find any workaround. I tried to debug, but could not find the answer. Is seems first the correct text is set, but then it is erased again.
(JDK 11.0.2, JavaFX 11.0.2, Netbeans 10)

Looks like a bug for me: for some reason the displayNode (that is the content of the buttonCell) is not updated on setting an uncontained value while a contained value is selected. Merely accessing the displayNode via its public api on ComboBoxBaseSkin triggers the correct setting.
To see it updating, add the following lines to your example and click that Button after the uncontained value is not showing:
Button display = new Button("getDisplayNode");
display.setOnAction(e -> {
((ComboBoxBaseSkin) testCombo.getSkin()).getDisplayNode();
});
To hack around the issue, we can extend the combo's skin and force the update in each layout pass:
public static class MyComboBoxSkin<T> extends ComboBoxListViewSkin<T> {
public MyComboBoxSkin(ComboBox<T> control) {
super(control);
}
#Override
protected void layoutChildren(double x, double y, double w, double h) {
super.layoutChildren(x, y, w, h);
// must be wrapped inside a runlater, either before or after calling super
Platform.runLater(this::getDisplayNode);
}
}
usage:
testCombo = new ComboBox<>(FXCollections.observableArrayList("Option 1", "Option 2", "Option 3")) {
#Override
protected Skin<?> createDefaultSkin() {
return new MyComboBoxSkin<>(this);
}
};
Note: the skin implementation makes heavy use of multiple boolean dirty flags, which seem to interact destructively in this particular case (don't understand how exactly, unfortunately). Delaying the access with a Platform.runlater seems to work.
Update
after some further digging, it looks like being a regression introduced by a lazy-dirty (not my wording, like it though :) fix. The custom cell implementation provided by Tom works nicely.

Answering my own question. I have found another possible workaround. It seems to work, although I am not sure it is "safe" (does button cell never need to be empty?).
The point is: using a custom button cell, override updateItem(T item, boolean empty) and (unlike in standard cell implementations), do nothing (return) for empty = true, i.e. do not erase the cell - no setText(null).
What is behind? It seems that the problem is not that the button cell text is not properly set, but that it is erased later by some "empty cell logic"...
You can add this code to my sample:
testCombo.setButtonCell(new ListCell<>() {
#Override
protected void updateItem(String item, boolean empty) {
super.updateItem(item, empty);
if (empty) {return;} // this is the solution: DO NOT ERASE ON empty=true!
// further logic copied from the solution in the default skin:
// see ComboBoxListViewSkin.updateDisplayText
// (default testing for "item instanceof Node" omitted for brevity)
final StringConverter<String> c = testCombo.getConverter();
final String promptText = testCombo.getPromptText();
String s = item == null && promptText != null ? promptText
: c == null ? (item == null ? null : item.toString()) : c.toString(item);
setText(s);
setGraphic(null);
}
});

ControlsFX: Ensure PopOver arrow always points to the right spot

I am using PopOver from ControlsFX, in a TableView If I trigger the startEdit of a cell, it should pop the PopOver. This part it works, the problem is, the arrow which is pointing to the row is not on the right place every time. If I select a row from the table which is at the bottom of the table , it points to a cell above it.
I need that arrow to point every time to the right cell in the TableView.
ControlsFX , version: 8.40.14
How can I solve this?
Here is the code where you can see how it works:
package stackoverflow.popover;
import com.sun.deploy.util.StringUtils;
import javafx.beans.property.ListProperty;
import javafx.beans.property.SimpleListProperty;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.Button;
import javafx.scene.control.ListView;
import javafx.scene.control.TableCell;
import javafx.scene.control.TableColumn;
import javafx.scene.control.TableView;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.StackPane;
import javafx.scene.layout.VBox;
import org.controlsfx.control.PopOver;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;
import java.util.ResourceBundle;
public class Controller implements Initializable {
#FXML
private TableView<Model> table;
#FXML
private TableColumn<Model, ObservableList<String>> listCell;
#Override
public void initialize(URL location, ResourceBundle resources) {
Model model = new Model(FXCollections.observableArrayList("Apple", "Peach"));
ObservableList<Model> items = FXCollections.observableArrayList();
for (int i = 0; i < 50; i++) {
items.add(model);
}
table.setItems(items);
table.setEditable(true);
listCell.setCellFactory(factory -> new ListTableCell(
FXCollections.observableArrayList("Apple", "Orange", "Peach", "Banana", "Lemon", "Lime")));
listCell.setCellValueFactory(data -> data.getValue().list);
}
private class ListTableCell extends TableCell<Model, ObservableList<String>> {
private ObservableList<String> allItems;
ListTableCell(ObservableList<String> allItems) {
this.allItems = allItems;
}
#Override
public void startEdit() {
super.startEdit();
PopOver popOver = new PopOver();
popOver.setAutoHide(true);
PopupController sc = new PopupController(allItems, new ArrayList<>(getItem()));
popOver.setContentNode(new StackPane(sc.getPane()));
popOver.setOnHiding(event -> commitEdit(sc.getItems()));
popOver.show(this);
}
#Override
protected void updateItem(ObservableList<String> item, boolean empty) {
super.updateItem(item, empty);
if (empty) {
setText(null);
} else {
setText(StringUtils.join(item, ","));
}
}
}
private class Model {
ListProperty<String> list;
public Model(ObservableList<String> list) {
this.list = new SimpleListProperty<>(list);
}
}
private class PopupController {
private BorderPane pane = new BorderPane();
private ListView<String> left = new ListView<>();
private ListView<String> right = new ListView<>();
private Button toLeft = new Button("<");
private Button toRight = new Button(">");
PopupController(List<String> all, List<String> selected) {
VBox leftBox = new VBox();
leftBox.setSpacing(5);
leftBox.getChildren().add(toRight);
leftBox.getChildren().add(left);
pane.setLeft(leftBox);
VBox rightBox = new VBox();
rightBox.setSpacing(5);
rightBox.getChildren().add(toLeft);
rightBox.getChildren().add(right);
pane.setRight(rightBox);
ObservableList<String> allItems = FXCollections.observableArrayList(all);
allItems.removeAll(selected);
left.setItems(allItems);
right.setItems(FXCollections.observableArrayList(selected));
toLeft.disableProperty().bind(right.getSelectionModel().selectedItemProperty().isNull());
toRight.disableProperty().bind(left.getSelectionModel().selectedItemProperty().isNull());
toLeft.setOnAction(event -> {
String str = right.getSelectionModel().getSelectedItem();
right.getItems().remove(str);
left.getItems().add(str);
});
toRight.setOnAction(event -> {
String str = left.getSelectionModel().getSelectedItem();
left.getItems().remove(str);
right.getItems().add(str);
});
}
BorderPane getPane() {
return pane;
}
ObservableList<String> getItems() {
return right.getItems();
}
}
}
Here are two screenshots to show what I mean :
This is even worst: (with setAutoFix(false))

I am not expert with ControlFX but I believe the problem you are facing its because the height of your PopOver is greater than your current screen size thus it is trying to relocate itself in a way to be inside the screen local bounds. So in order to achieve what you are trying you will need to manually set the ArrowLocation of your PopOver control. Here is how you can solve the issue (using your code) :
#Override
public void startEdit() {
super.startEdit();
PopOver popOver = new PopOver();
popOver.setAutoHide(true);
// first set auto fix to false
// to manually set the arrow location
popOver.setAutoFix(false);
PopupController sc = new PopupController(allItems, new ArrayList<>(getItem()));
// set a specific height for our pane
final double paneHeight = 300;
StackPane popOverPane = new StackPane(sc.getPane());
popOverPane.setPrefHeight(paneHeight);
popOver.setContentNode(popOverPane);
popOver.setOnHiding(event -> commitEdit(sc.getItems()));
// find coordinates relative to the screen
Bounds screenBounds = this.localToScreen(this.getBoundsInLocal());
// get our current y position ( on screen )
int yPos = (int) screenBounds.getMinY();
// get screen size
Rectangle2D primaryScreenBounds = Screen.getPrimary().getVisualBounds();
int screenHeight = (int) primaryScreenBounds.getHeight();
// if the PopOver height + the current position is greater than
// the max screen's height then set the arrow position to bottom left
if(screenHeight < yPos + paneHeight) {
popOver.setArrowLocation(ArrowLocation.LEFT_BOTTOM);
}
popOver.show(this);
}
Using the code above you would see some things you need to change and think more carefully.
The first one is that you will need to set a specific size for your StackPane or to find a dynamic way to calculate it.
Secondly in my example I am using the Screen.getPrimary() which will get the Rectangle2D dimensions of your primary screen and not the screen you have your application, this means that if you have more monitors with different resolution and your program is displayed on the second one, the code above will still use the first ( default ) monitor's resolution which might not match with the primary one, so you will have to find a way to get the correct monitor resolution.
Lastly you will need to do the same when the window is on the right side of the screen because then the width of the 'Popover' will exceed the width of your monitor

Try setting setAutoFix(false) on the PopOver instance. From the documentation of the autoFix property of the PopOver's superclass PopupWindow:
This convenience variable indicates whether, when the popup is shown,
it should automatically correct its position such that it doesn't end
up positioned off the screen.

JavaFX - Notify when user drags mouse from one Node to another?

I have the following basic GUI for demonstration:
I'm trying to achieve the following functionality but I've exhausted all avenues that I've attempted.
User can left click on any of the ImageView's and it will create an
arrow that follows the user's cursor around until the user let's go of
the mouse button. (arrow start x,y is where he clicked and end x,y is
where his mouse currently is) If the user clicked on the Red
ImageView and dragged it over the Blue ImageView and then let go,
the program would print User just clicked from R to B
If the user clicked on the Red ImageView and let go of the mouse but
was not over a different ImageView, the program would print User
just clicked from R but did not target a different ImageView.
Under all circumstances, the arrow will appear when the user clicks on
the ImageView and will disappear the second he lets go of the mouse.
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.image.Image;
import javafx.scene.image.ImageView;
import javafx.scene.layout.Pane;
import javafx.scene.shape.Line;
import javafx.stage.Stage;
import java.util.HashMap;
public class Test extends Application
{
public static int HEIGHT = 500, WIDTH = 600;
#Override
public void start(Stage primaryStage) throws Exception
{
ImageView blue = new ImageView(new Image("blue.png")),
red = new ImageView(new Image("red.png")),
dark = new ImageView(new Image("dark.png"));
// Final array as to bypass the `final` requirement of event handler inner classes.
final ImageView[] hoveredOver = new ImageView[1];
final Line[] linePtr = new Line[1];
linePtr[0] = new Line();
linePtr[0].setStrokeWidth(10);
HashMap<ImageView, Character> lookup = new HashMap<ImageView, Character>(3)
{{
put(blue, 'B');
put(red, 'R');
put(dark, 'D');
}};
for (ImageView i : new ImageView[] { blue, red, dark })
{
i.setFitWidth(150);
i.setFitHeight(150);
// Set the anchor points of the click and display the arrow.
i.setOnMousePressed(e -> {
linePtr[0].setStartX(e.getX());
linePtr[0].setStartY(e.getY());
linePtr[0].setVisible(true);
});
// Move the arrow as the mouse moves.
i.setOnMouseDragged(e -> {
linePtr[0].setEndX(e.getX());
linePtr[0].setEndY(e.getY());
});
i.setOnMouseReleased(e -> {
// Not null means that the user WAS actually just now hovering over an imageview.
if (hoveredOver[0] != null)
System.out.printf("The user clicked from %c to %c!\n", lookup.get(i), lookup.get(hoveredOver[0]));
// Null means the user is not over an ImageView.
else
System.out.printf("The user initially clicked %c but did not drag to another Imageview.\n", lookup.get(i));
linePtr[0].setVisible(false);
});
// If the user enters ANY of the ImageViews,
// Set a variable so that the drag release listener
// can know about it!
i.setOnMouseDragOver(e -> hoveredOver[0] = i);
i.setOnMouseDragExited(e -> hoveredOver[0] = null);
}
blue.setX(400);
blue.setY(250);
red.setY(300);
red.setX(50);
/*
In this example I'm using a Pane but in my real program
I might be using a VBOX HBOX etc where I cannot freely move stuff around as I'd like.
This makes things extremely difficult and without using a 'Pane'
I don't know how this can even be done. Suggestions?
*/
Pane pneRoot = new Pane(blue, red, dark, linePtr[0]);
Scene scene = new Scene(pneRoot, WIDTH, HEIGHT);
primaryStage.setScene(scene);
primaryStage.show();
}
public static void main(String[] args)
{
launch(args);
}
}
This was my best attempt and it's not even close. It moves a line (not an arrow, and ideally I want my arrow to curve as it moves much like this example image from a popular video game) but does not suit my needs. It cannot detect however when I let go while 'dragging over' an ImageView.
Is there a better way to do this? I feel like I can't simply the code I have down any further but there MUST be another way.

Java is an object-oriented language. The basic idea is that you create classes to represent the data you are modeling and then create objects from those classes. If you are tying things together with arbitrary maps to look things up, and arrays kicking around for no apparent reason, you are starting in the wrong place.
JavaFX has a system of observable properties. These wrap objects in a mutable way and can be observed so you can respond to changes.
Make sure you read and understand the documentation on MouseEvents and MouseDragEvents. There are three different modes for handling dragging. For events (mouse drag events) to be sent to nodes other than the one on which the drag was initiated during a mouse drag, you need to be in full "press-drag-release gesture" mode. You can activate this mode by calling startFullDrag() on the node when responding to a dragDetected event.
I would start with something like
public class NamedDragAwareImageView {
private final ObjectProperty<NamedDragAwareImageView> source ;
private final ObjectProperty<NamedDragAwareImageView> destination ;
private final String name ;
private final ImageView imageView ;
public NamedDragAwareImageView(ObjectProperty<NamedDragAwareImageView> source,
ObjectProperty<NamedDragAwareImageView> destination,
String name, String resource) {
this.source = source ;
this.destination = destination ;
this.name = name ;
this.imageView = new ImageView(new Image(resource));
imageView.setOnDragDetected(e -> {
source.set(this);
destination.set(null);
imageView.startFullDrag();
});
imageView.setOnMouseDragReleased(e -> {
if (source.get() != null && source.get() != this) {
destination.set(this);
}
});
// other image view config...
}
public ImageView getView() {
return imageView ;
}
public String getName() {
return name ;
}
}
Then you can do things like:
// observable properties to represent start and end nodes for drag:
ObjectProperty<NamedDragAwareImageView> source = new SimpleObjectProperty<>();
ObjectProperty<NamedDragAwareImageView> destination = new SimpleObjectProperty<>();
Pane root = new Pane();
// create your named image views, referencing the source and destination
// and add their image views to root, e.g.
NamedDragAwareImageView red = new NamedDragAwareImageView(source, destination, "Red", "red.png");
root.getChildren().add(red.getView());
// recommend using SVG paths (i.e. javafx.scene.shape.Path) for the arrow
// easy to draw programmatically, easy to manipulate elements etc:
Path arrowHead = new Path();
MoveTo arrowHeadStart = new MoveTo();
arrowHead.getElements().add(arrowHeadStart);
arrowHead.getElements().addAll(/* draw an arrow head with relative path elements... */);
arrowHead.setVisible(false);
// avoid arrowHead interfering with dragging:
arrowHead.setMouseTransparent(true);
// this will contain a MoveTo and a bunch of LineTo to follow the mouse:
Path arrowLine = new Path();
arrowLine.setMouseTransparent(true);
root.getChildren().addAll(arrowHead, arrowLine);
// change listener for source. source is set when drag starts:
source.addListener((obs, oldSource, newSource) -> {
if (newSource == null) return ;
arrowHeadStart.setX(/* x coord based on newSource */);
arrowHeadStart.setY(/* similarly */);
arrowHead.setVisible(true);
});
// change listener for destination. destination is only set
// when drag complete:
destination.addListener((obs, oldDestination, newDestination) -> {
if (newDestination != null) {
System.out.println("User dragged from "+source.get().getName()+
" to "+destination.get().getName());
}
});
root.setOnMouseDragOver(e -> {
if (source.get()==null && destination.get()!=null) {
// update arrowStart position
// add line element to arrowLine
}
});
root.setOnMouseReleased(e -> {
// clear arrow:
arrowHead.setVisible(false);
arrowLine.getElements().clear();
});

JavaFX How do I return the cursor to the first line in TextArea? [duplicate]

I want to use a JavaFX TextArea as though it were exactly like a multi-line TextField. In other words, when I press [Tab] I want to cycle to the next control on the form and when I press [Enter] I want the Key.Event to go to the defaultButton control (rather than be consumed by the TextArea).
The default behavior for TextArea is that [Tab] gets inserted into the TextArea and [Enter] inserts a new-line character.
I know that I need to use EventFilters to get the behavior that I want, but I'm getting it all wrong. I don't want the TextArea to consume these events ... I just want it to let them "go right on by".

The solution here displays two text areas and a default button.
When the user presses the tab key, the focus moves to the next control down.
When the user presses the enter key, the default button is fired.
To achieve this behavior:
The enter key press for each text area is caught in an event filter, copied and targeted to the text area's parent node (which contains the default OK button). This causes the default OK button to be fired when enter is pressed anywhere on the form. The original enter key press is consumed so that it does not cause a new line to be added to the text area's text.
The tab key press for each text area is caught in a filter and the parent's focus traversable list is processed to find the next focusable control and focus is requested for that control. The original tab key press is consumed so that it does not cause new tab spacing to be added to the text area's text.
The code makes use of features implemented in Java 8, so Java 8 is required to execute it.
import javafx.application.Application;
import static javafx.application.Application.launch;
import javafx.beans.value.*;
import javafx.collections.ObservableList;
import javafx.event.*;
import javafx.scene.*;
import javafx.scene.control.*;
import static javafx.scene.input.KeyCode.ENTER;
import static javafx.scene.input.KeyCode.TAB;
import javafx.scene.input.KeyEvent;
import javafx.scene.layout.VBox;
import javafx.stage.*;
public class TextAreaTabAndEnterHandler extends Application {
final Label status = new Label();
public static void main(String[] args) { launch(args); }
#Override public void start(final Stage stage) {
final TextArea textArea1 = new TabAndEnterIgnoringTextArea();
final TextArea textArea2 = new TabAndEnterIgnoringTextArea();
final Button defaultButton = new Button("OK");
defaultButton.setDefaultButton(true);
defaultButton.setOnAction(new EventHandler<ActionEvent>() {
#Override public void handle(ActionEvent event) {
status.setText("Default Button Pressed");
}
});
textArea1.textProperty().addListener(new ClearStatusListener());
textArea2.textProperty().addListener(new ClearStatusListener());
VBox layout = new VBox(10);
layout.setStyle("-fx-background-color: cornsilk; -fx-padding: 10px;");
layout.getChildren().setAll(
textArea1,
textArea2,
defaultButton,
status
);
stage.setScene(
new Scene(layout)
);
stage.show();
}
class ClearStatusListener implements ChangeListener<String> {
#Override public void changed(ObservableValue<? extends String> observable, String oldValue, String newValue) {
status.setText("");
}
}
class TabAndEnterIgnoringTextArea extends TextArea {
final TextArea myTextArea = this;
TabAndEnterIgnoringTextArea() {
addEventFilter(KeyEvent.KEY_PRESSED, new TabAndEnterHandler());
}
class TabAndEnterHandler implements EventHandler<KeyEvent> {
private KeyEvent recodedEvent;
#Override public void handle(KeyEvent event) {
if (recodedEvent != null) {
recodedEvent = null;
return;
}
Parent parent = myTextArea.getParent();
if (parent != null) {
switch (event.getCode()) {
case ENTER:
if (event.isControlDown()) {
recodedEvent = recodeWithoutControlDown(event);
myTextArea.fireEvent(recodedEvent);
} else {
Event parentEvent = event.copyFor(parent, parent);
myTextArea.getParent().fireEvent(parentEvent);
}
event.consume();
break;
case TAB:
if (event.isControlDown()) {
recodedEvent = recodeWithoutControlDown(event);
myTextArea.fireEvent(recodedEvent);
} else {
ObservableList<Node> children = parent.getChildrenUnmodifiable();
int idx = children.indexOf(myTextArea);
if (idx >= 0) {
for (int i = idx + 1; i < children.size(); i++) {
if (children.get(i).isFocusTraversable()) {
children.get(i).requestFocus();
break;
}
}
for (int i = 0; i < idx; i++) {
if (children.get(i).isFocusTraversable()) {
children.get(i).requestFocus();
break;
}
}
}
}
event.consume();
break;
}
}
}
private KeyEvent recodeWithoutControlDown(KeyEvent event) {
return new KeyEvent(
event.getEventType(),
event.getCharacter(),
event.getText(),
event.getCode(),
event.isShiftDown(),
false,
event.isAltDown(),
event.isMetaDown()
);
}
}
}
}
An alternate solution would be to implement your own customized skin for TextArea which includes new key handling behavior. I believe that such a process would be more complicated than the solution presented here.
Update
One thing I didn't really like about my original solution to this problem was that once the Tab or Enter key was consumed, there was no way to trigger their default processing. So I updated the solution such that if the user holds the control key down when pressing Tab or Enter, the default Tab or Enter operation will be performed. This updated logic allows the user to insert a new line or tab space into the text area by pressing CTRL+Enter or CTRL+Tab.

JavaFX - Sequential Transition - playing back and forth (step by step)

I'm struggling with making an animation showing the searchin in Binary Search Tree in JavaFX.
The goal is to make a visualization of comparing the value of tree node with possibility to:
pause and play it any time
being able to play the animation backwards (to go at least one step back),
give a user an ability to play the animation step-by-step or whole at once.
The preview of visualization
My vision was to make a series of TranslateTransitions(TT) added in one SequentialTransition(ST). If the animation is marked as "step-by-step" the each TT pauses the whole ST in their OnFinished handler. However this kinda works only for going one-way.
My question is. What is the best approach to maintain going fluent and step-by-step animation in reverse direction ?
I was thinking about:
maybe making another sequence of inverse transitions (but how to tell
it from which step to continue ?)
somehow work with rate property ? is it possible to change it while the ST is running ?
Thank you very much for your answers.

In general, you can change the rate property of an Animation while it is in progress. The idea of using a SequentialTransition is appealing, but it doesn't work as easily as you might think. The problem arises when the sequential transition is paused at the boundary between two individual transitions: you don't have any way to tell which of the individual transitions is considered the current one (i.e. the next one or the previous one). So when you try to reverse the rate and play, the sequential transition can get confused and immediately think it's at the end of the one it's trying to play.
You might be able to hack this a little by using Animation.getCurrentTime() and Animation.jumpTo(...) to "nudge" the sequential transition a tiny amount in the correct direction before starting to play any step, but I think it's probably easier just to manage the individual transitions on their own instead of using a SequentialTransition.
Here's a simple example of using this technique to move a rectangle around:
import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;
import javafx.animation.Animation;
import javafx.animation.Animation.Status;
import javafx.animation.TranslateTransition;
import javafx.application.Application;
import javafx.beans.binding.Bindings;
import javafx.beans.binding.BooleanBinding;
import javafx.beans.property.IntegerProperty;
import javafx.beans.property.SimpleIntegerProperty;
import javafx.beans.value.ObservableValue;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.HBox;
import javafx.scene.layout.Pane;
import javafx.scene.paint.Color;
import javafx.scene.shape.Rectangle;
import javafx.stage.Stage;
import javafx.util.Duration;
public class ReverseSequentialTransitionTest extends Application {
#Override
public void start(Stage primaryStage) {
Pane pane = new Pane();
Rectangle rect = new Rectangle(50, 50, 250, 150);
rect.setFill(Color.color(.5, .5, .1));
pane.getChildren().add(rect);
TranslateTransition ttForward = new TranslateTransition(Duration.seconds(1), rect);
ttForward.setFromX(0);
ttForward.setToX(400);
TranslateTransition ttDown = new TranslateTransition(Duration.seconds(1), rect);
ttDown.setFromY(0);
ttDown.setToY(100);
TranslateTransition ttBackward = new TranslateTransition(Duration.seconds(1), rect);
ttBackward.setFromX(400);
ttBackward.setToX(0);
TranslateTransition ttUp = new TranslateTransition(Duration.seconds(1), rect);
ttUp.setFromY(100);
ttUp.setToY(0);
List<Animation> transitions = Arrays.asList(ttForward, ttDown, ttBackward, ttUp);
IntegerProperty nextTransitionIndex = new SimpleIntegerProperty();
Button playButton = new Button("Play Forward");
playButton.setOnAction(event -> {
int index = nextTransitionIndex.get();
Animation anim = transitions.get(index);
anim.setOnFinished(evt -> nextTransitionIndex.set(index+1));
anim.setRate(1);
anim.play();
});
Button reverseButton = new Button("Play backward");
reverseButton.setOnAction(event -> {
int index = nextTransitionIndex.get()-1;
Animation anim = transitions.get(index);
anim.setOnFinished(evt -> nextTransitionIndex.set(index));
anim.setRate(-1);
anim.play();
});
// This is not really part of the answer to the current question, but the
// next three statements just disable the buttons when appropriate.
// This is a binding which is true if and only if any of the transitions are
// currently running:
BooleanBinding anyPlaying = createAnyPlayingBinding(transitions);
// Disable playButton if we are at the end of the last transition, or if
// any transitions are playing:
playButton.disableProperty().bind(
nextTransitionIndex.greaterThanOrEqualTo(transitions.size())
.or(anyPlaying)
);
// Disable reverseButton if we are at the beginning of the first transition,
// or if any transitions are currently playing:
reverseButton.disableProperty().bind(
nextTransitionIndex.lessThanOrEqualTo(0)
.or(anyPlaying));
HBox controls = new HBox(5);
controls.setAlignment(Pos.CENTER);
controls.getChildren().addAll(playButton, reverseButton);
BorderPane root = new BorderPane();
root.setCenter(pane);
root.setBottom(controls);
primaryStage.setScene(new Scene(root, 800, 400));
primaryStage.show();
}
private BooleanBinding createAnyPlayingBinding(List<Animation> transitions) {
return new BooleanBinding() {
{ // Anonymous constructor
// bind to the status properties of all the transitions
// (i.e. mark this binding as invalid if any of the status properties change)
transitions.stream()
.map(Animation::statusProperty)
.forEach(this::bind);
}
#Override
protected boolean computeValue() {
// return true if any of the transitions statuses are equal to RUNNING:
return transitions.stream()
.anyMatch(anim -> anim.getStatus()==Status.RUNNING);
}
};
}
public static void main(String[] args) {
launch(args);
}
}
In JDK 7, the event handler for the playButton looks like this:
playButton.setOnAction(new EventHandler<ActionEvent>() {
#Override
public void handle(ActionEvent event) {
final int index = nextTransitionIndex.get();
Animation anim = transitions.get(index);
anim.setOnFinished(new EventHandler<ActionEvent>() {
#Override
public void handle(ActionEvent evt) {
nextTransitionIndex.set(index + 1) ;
}
});
anim.setRate(1);
anim.play();
}
});
and similarly for reverseButton. You will need to declare a couple of things as final as well. The createAnyPlayingBinding method is something like
private BooleanBinding createAnyPlayingBinding(final List<Animation> transitions) {
return new BooleanBinding() {
{
for (Animation transition : transitions) {
this.bind(transition.statusProperty();
}
}
#Override
protected boolean computeValue() {
// return true if any of the transitions statuses are equal to RUNNING:
for (Animation anim : transitions) {
if (anim.getStatus() == Status.RUNNING) {
return true ;
}
}
return false ;
}
};
}