We Keep Coding

Mouse release event doesn't happen on Ubuntu when target Node changes scene?

This question deals with mouse behavior across operating systems; specifically, my code works on Windows and Mac OS X, but not on Ubuntu.
Ultimately what I am trying to do is make a special Pane subclass ("ConvertiblePane") that exists within a parent Pane on a main stage/scene, but is magically transferred into its own temporary stage/scene when dragged, thus becoming independent and able to be placed anywhere on the screen. When the user releases the mouse button, the ConvertiblePane should drop back onto its original parent Pane and lose the temporary stage. (In my full program, the original parent Stage resizes/repositions itself to accommodate the ConvertiblePane wherever it is dropped.)
This brings me to my issue. When I press the mouse on the ConvertiblePane, it triggers a MousePress within the main scene as expected, at which point the ConvertiblePane is moved to the temporary stage. As I drag the mouse, it triggers MouseDrag within the temporary scene and moves the temp stage. Ok, great.
When I release the mouse button, however, I experience different behavior on different operating systems. On Windows (7) and Mac OS X (10.12.6), a MouseRelease occurs in the temp scene, sending the pane back to its original parent in the main stage as expected. On Ubuntu, however, no MouseRelease seems to be generated in either the main scene or the temp scene.
Here's the relevant code as an MCV example:
import javafx.application.Application;
import javafx.geometry.Insets;
import javafx.geometry.Point2D;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.input.MouseEvent;
import javafx.scene.layout.Background;
import javafx.scene.layout.BackgroundFill;
import javafx.scene.layout.CornerRadii;
import javafx.scene.layout.Pane;
import javafx.scene.paint.Color;
import javafx.stage.Stage;
import javafx.stage.StageStyle;
public class ConvertibleTest extends Application {
#Override
public void start(Stage primaryStage) {
// Set up the main stage and scene with a
// Pane as root and a ConvertiblePane child:
primaryStage.initStyle(StageStyle.TRANSPARENT);
Pane root = new Pane();
ConvertiblePane conv = new ConvertiblePane();
root.getChildren().add(conv);
Scene scene = new Scene(root, 400, 400, Color.PINK);
primaryStage.setTitle("Convertible Test");
primaryStage.setScene(scene);
primaryStage.show();
}
public static void main(String[] args) {
launch(args);
}
}
class ConvertiblePane extends Pane
{
private final Group TEMP_ROOT = new Group();
private final Stage TEMP_STAGE = new Stage(StageStyle.TRANSPARENT);
private final Scene TEMP_SCENE = new Scene(TEMP_ROOT);
private Pane originalParent = null;
private double deltaX = 0.0;
private double deltaY = 0.0;
private String name = null;
public void onMousePress(MouseEvent event)
{
// Save deltaX/Y for later:
Point2D delta = this.sceneToLocal(event.getX(), event.getY());
deltaX = delta.getX();
deltaY = delta.getY();
if (!isIndependent())
{
makeIndependent();
}
}
public void onMouseDrag(MouseEvent event)
{
// Keep the TEMP_STAGE relative to the original click point:
TEMP_STAGE.setX(event.getScreenX()-deltaX);
TEMP_STAGE.setY(event.getScreenY()-deltaY);
}
public void onMouseRelease(MouseEvent event)
{
if (isIndependent())
{
returnToParent();
}
}
public ConvertiblePane()
{
this.setPrefSize(100, 100);
this.setBackground(new Background(new BackgroundFill(Color.GREEN, new CornerRadii(10), Insets.EMPTY)));
this.setVisible(true);
// Attach event code and report to System.out what is happening:
this.setOnMousePressed((MouseEvent event) -> {
if (this.getScene() == TEMP_SCENE)
System.out.println("Pressed as Independent");
else
System.out.println("Pressed as Child");
onMousePress(event);
});
this.setOnMouseDragged((MouseEvent event) -> {
if (this.getScene() == TEMP_SCENE)
System.out.println("Dragged as Independent");
else
System.out.println("Dragged as Child");
onMouseDrag(event);
});
this.setOnMouseReleased((MouseEvent event) -> {
if (this.getScene() == TEMP_SCENE)
System.out.println("Released as Independent");
else
System.out.println("Released as Child");
onMouseRelease(event);
});
}
public boolean isIndependent()
{
// Return whether this ConvertiblePane is "independent" (exists in its own temp scene)
return this.getScene() == TEMP_SCENE;
}
public void makeIndependent()
{
// Get the point where this ConvertiblePane appears on screen:
Point2D screenPt = this.localToScreen(0, 0);
// Save the originaParent of this ConvertiblePane; we will return to it later:
originalParent = (Pane)getParent();
// Remove this ConvertiblePane from its originalParent:
originalParent.getChildren().remove(this);
// Set this ConvertiblePane as the root of the TEMP_SCENE on the TEMP_STAGE:
TEMP_SCENE.setRoot(this);
TEMP_STAGE.setScene(TEMP_SCENE);
System.out.println("Transferred to TEMP.");
this.relocate(0, 0);
// Show the TEMP_STAGE in the same location on screen where this ConvertiblePane originally was:
TEMP_STAGE.setX(screenPt.getX());
TEMP_STAGE.setY(screenPt.getY());
TEMP_STAGE.show();
}
public void returnToParent()
{
// Reset deltas:
deltaX = 0;
deltaY = 0;
// Get the location of this ConvertiblePane on screen:
Point2D screenPt = this.localToScreen(0, 0);
// Set TEMP_ROOT as the root of TEMP_SCENE; this will allow us to detach
// this ConvertiblePane from being the scene root (since root cannot == null).
TEMP_SCENE.setRoot(TEMP_ROOT);
// Hide the TEMP_STAGE:
TEMP_STAGE.hide();
// Add this ConvertiblePane back to the originalParent:
originalParent.getChildren().add(this);
System.out.println("Transferred to MAIN.");
// Relocate this ConvertiblePane within the originalParent to maintain its position on screen
Point2D parentPt = originalParent.screenToLocal(screenPt);
this.relocate(parentPt.getX(), parentPt.getY());
}
}
As you can see, there is some basic reporting in the event handling methods; and the makeIndependent() and returnToParent() methods output "Transferred to TEMP." and "Transferred to MAIN." respectively.
If I click the mouse on the ConvertiblePane, drag a few pixels, and release it, this is the output:
(on Windows or Mac OS X)
Pressed as Child
Transferred to TEMP.
Dragged as Independent
Dragged as Independent
Dragged as Independent
Released as Independent
Transferred to MAIN.
(on Ubuntu)
Pressed as Child
Transferred to TEMP.
Dragged as Independent
Dragged as Independent
Dragged as Independent
I have also tried adding event filters to the two Scenes; but the result is the same: MouseRelease occurs on Win/Mac, but not Ubuntu.
If anyone can explain this behavior, or suggest something, that would be great. Alternatively... is there any "global" (pre-scene) creation of MouseEvents that I could catch? I mean, I don't really care about the details of the mouse release; I just want an event to tell me when to add the ConvertiblePane back to the main stage.
Thanks!

After spending several weeks on this, I couldn't find a way to fire a proper MouseReleased event on Ubuntu for this situation; however, I did come up with a hack that does the job well enough. Basically, instead of being notified when MouseReleased occurs, I'm checking every 10 milliseconds to see whether the mouse button is no longer down.
Explanation: When the node is transferred to the temporary Scene, the Timeline is started to "move" the mouse pointer in place every 10 milliseconds. This triggers either a MouseDragged event (if the mouse button is still down) or a MouseMoved event (if the mouse button is up); so I can then simulate the MouseReleased event and call my procedure for adding the node back to the main stage. At that point, of course, I also stop the Timeline.
Here's the relevant code to demonstrate this; perhaps it will be of use to someone else as well.
// The robot is needed to "move" the mouse in place,
// triggering a MOUSE_MOVED event.
private static Robot robot = null;
static {
try {
robot = new Robot();
} catch (AWTException ex) {
Logger.getLogger(ConvertiblePane.class.getName()).log(Level.SEVERE, null, ex);
}
}
// clickWaiter will move the mouse in place every 10 milliseconds,
// triggering a MOUSE_MOVED event if the mouse is no longer pressed.
private final Timeline clickWaiter = new Timeline(new KeyFrame(Duration.millis(10), (ActionEvent event) -> {
// Get the mouse position from MouseInfo class.
Point mouse = MouseInfo.getPointerInfo().getLocation();
// "Move" the mouse in place to trigger a mouseMove or mouseDrag event.
robot.mouseMove(mouse.x, mouse.y);
}));
public ConvertiblePane()
{
...
// MOUSE_MOVED will be triggered by the robot when the mouse button is no longer pressed:
TEMP_SCENE.addEventFilter(MouseEvent.MOUSE_MOVED, (MouseEvent event) ->
{
if (!event.isPrimaryButtonDown())
{
System.out.println("Temp.release (sim)");
clickWaiter.stop();
// Simulate MOUSE_RELEASED event.
}
});
}
public void makeIndependent()
{
...
// Start the clickWaiter, part of the Linux hack:
clickWaiter.playFromStart();
}

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 thread issues

I really do my best to not ask for help here unless i am desperate to the point of school assignment failure, being a new coder. That being said, i have spent the last 3 days trying to figure out the issue with threading. I am trying to instantiate a javafx class thats in a separate package, and keep running into the dreaded "java.lang.IllegalStateException: This operation is permitted on the event thread only; currentThread = main" exception.
I have tried calling theGamePreBoard.start(new Stage()), which doesnt work, and i have also tried calling its start method during construction of that object with a new Stage() passed in during construction. Please help!!!
How can i instantiate this PreBoard() class and get it's start method to run without throwing this?
main class:
/*
* To change this license header, choose License Headers in Project Properties.
* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
package battleship.model;
import battleship.viewcon.*;
import javafx.stage.Stage;
/**
*
* #author foolishklown
*/
public class MainApp {
Player player1;
Player player2;
Board board1;
Board board2;
BattleshipGame theGame;
PreBoard theGamePreBoard;
public void go() {
theGame = new BattleshipGame();
theGamePreBoard = new PreBoard();
theGamePreBoard.start(new Stage());
System.out.println(theGamePreBoard);
theGamePreBoard.setBattleshipGame(theGame);
}
public static void main(String[] args) {
MainApp app = new MainApp();
app.go();
}
}
PreBoard class:
/*
* PreBoard object. This is the starter class for the different JavaFX stages (different windows - username screen,
* and each players window)
* After first username input, this class hides and calls on a new P1Board object
*/
package battleship.viewcon;
import battleship.model.*;
import javafx.geometry.Insets;
import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.layout.GridPane;
import javafx.scene.text.Text;
import javafx.stage.Stage;
import javafx.scene.control.Label;
import javafx.scene.control.TextField;
import javafx.scene.layout.HBox;
/**
*
*
* #author c-dub
*/
public class PreBoard extends Application {
private boolean turn; // field to determine which players name to put into which board
private String player;
private Button hideBtn;
private Button showBtn;
private TextField userText;
private ViewCon controller;
private P1Board p1B;
private P2Board p2B;
private BattleshipGame game;
private Stage theStage;
#Override
public void start(Stage primaryStage) {
turn = false;
p1B = new P1Board();
p2B = new P2Board();
controller = new ViewCon();
controller.setp1(p1B);
controller.setp2(p2B);
controller.setPreB(this);
this.game = controller.getBattleshipGame();
primaryStage.setTitle("Battleship setup"); //Main stage (window container)
//Gridpane for using rows/columns for child node placement
GridPane grid = new GridPane();
grid.setAlignment(Pos.CENTER_LEFT);
grid.setHgap(10);
grid.setVgap(5);
grid.setPadding(new Insets(100, 25, 25, 25));
// label in window
Text sceneTitle = new Text("Setup");
sceneTitle.setId("setup-text");
grid.add(sceneTitle, 0, 0, 2, 1);
// label and textfield
Label userName = new Label("Enter UserName:");
userName.setId("user-name");
grid.add(userName, 0, 1);
TextField userTextField = new TextField();
userTextField.setId("text-field");
grid.add(userTextField, 0, 2);
// button for setup, with actionListener to save player name or default if its left blank
Button setupBtn = new Button("Setup Board");
HBox hbBtn = new HBox(10);
hbBtn.setAlignment(Pos.BOTTOM_LEFT);
hbBtn.getChildren().add(setupBtn);
grid.add(hbBtn, 0, 3);
setupBtn.setOnAction(new EventHandler<ActionEvent>() {
#Override
public void handle(ActionEvent e) {
// determine which player name to use to pass into which player board
if(turn == false) {
String temp1 = userTextField.getText();
if(temp1.equals("")) {
player = "Player1";
} else {
player = temp1;
}
controller.setPlayer1(player);
game.setPlayer1(player);
turn = true;
Stage stage = new Stage();
p1B.start(stage);
grid.getChildren().remove(userTextField);
userText = new TextField();
userText.setId("text-field2");
grid.add(userText, 0, 2);
hideBtn.fire();
} else {
String temp2 = userText.getText();
if(temp2.equals("")) {
player = "Player2";
} else {
player = temp2;
}
controller.setPlayer2(player);
game.setPlayer2(player);
Stage stage2 = new Stage();
p2B.start(stage2);
hideBtn.fire();
}
}
});
hideBtn = new Button();
hideBtn.setId("hideBtn");
hideBtn.setOnAction(new EventHandler<ActionEvent>() {
#Override
public void handle(ActionEvent e) {
primaryStage.hide();
}
});
showBtn = new Button();
showBtn.setId("showBtn");
showBtn.setOnAction(new EventHandler<ActionEvent>() {
#Override
public void handle(ActionEvent e) {
primaryStage.show();
}
});
controller.setPreShowBtn(showBtn);
controller.setPreHideBtn(hideBtn);
// Add the entire scene into the main window(stage) after setting the scene dimensions
Scene scene = new Scene(grid, 580, 200);
primaryStage.setScene(scene);
// Attach css stylesheet
scene.getStylesheets().add(PreBoard.class.getResource("styles/PreBoardStyle.css").toExternalForm());
// Show this window(stage) upon instantiation
primaryStage.show();
}
public void setLink(ViewCon v) {
this.controller = v;
}
public static void main(String[] args) {
Application.launch(args);
}
public void setBattleshipGame(BattleshipGame b) {
this.game = b;
}
}

I don't think this has anything at all to do with threading: I don't see any reason why you would ever create another thread in this application. The part you seem to be missing is the actual life-cycle of a JavaFX application. (There's a little you could need to know about how JavaFX manages threading, but it is a bit incidental here.)
The Application class represents an entire application. Your application should typically have just one Application subclass, and one instance of that class. The instance is created for you by JavaFX when you call the static Application.launch() method (or when you execute your Application subclass from the command line, which effectively calls launch for you).
When launch is invoked, the JavaFX toolkit (including the FX Application Thread) is started. An instance of theApplication subclass is created for you, and then start(...) is invoked on that instance on the FX Application Thread.
So what that means is that the start(...) method is the entry point (startup) for your JavaFX application. Since the most common thing to do here is to display something in a window, a window (Stage) is passed into this method for your convenience: however you can ignore it and just create your own if you like.
A typical start(...) method should be quite short, and will usually just create some UI (maybe defined in another class or in an FXML file), put that UI in a scene, and display the scene in a stage. In a more complex application, you will create an instance of your model class here, create some views and controllers, give the controllers references to the model, and assemble the views.
For a simple structural example, see my answer to Java: How do I start a standalone application from the current one when both are in the same package? (which is a similar question, I think).

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 KeyEvent propagation order

I want to listen to some KeyEvent in my scene, say KeyCode.ESCAPE(close the scene when pressed).
scene.addEventHandler(KeyEvent.ANY, event -> {
if (event.isConsumed())
return;
switch (event.getCode()) {
case ESCAPE:
stage.hide();
event.consume();
break;
default:
break;
}
});
Now, the nodes inside the scene could have listened to ESCAPE too.
// ....
someOtherNode.addEventHandler(KeyEvent.ANY, e -> {
if (e.getCode() == KeyCode.ESCAPE) {
// do stuff
e.consume();
}
});
// ....
How do I make sure that the KeyEvent will be consumed from the node and not the scene?
Based on the diagram from Oracle, A workaround would be adding a dummy Node at the end of the Node hierarchy that listens to KeyCodes
But is there a better solution, like inverting the propagation route?
EDIT:
The use case:
A popup-like node that blocks other nodes would need to listens to the ESC key or focusProperty() so that it can close itself.

There's two ways you can affect events:
Use the Node.addEventFilter(...) method to register a filter. A filter will execute on the capturing phase of the event (as the window is getting more specific, determining which Nodes should get the event).
Use the Node.addEventHandler(...) method to register a handler. The handler will execute starting at the most specific node found in the capturing phase, heading down until it is consumed.
So in the capturing phase, a stack is created. Starting with the window (topmost parent), each node that this event could potentially execute on is added to the stack (ending with the bottom most child). A filter can interrupt this process, or just execute an event during this process.
In the bubbling phase, the event handlers will start firing from the top of the stack (created in the capturing phase) until the stack is empty or the event is consumed.
In your case, you really shouldn't have anything to worry about. If any node cares about processing the "ESC" event, they will do so in the bubbling phase (and they should consume the event to prevent further processing). You can see this behavior in the ComboBox. If they don't care, it will bubble up to your Scene and that handler will execute. Just make sure any custom code you create that processes an "ESC" press also consumes that event.
For more information, there is a explanation and tutorial here: http://docs.oracle.com/javafx/2/events/jfxpub-events.htm
And here is some sample code demonstrating the Escape functionality. Pressing ESC while focused on the ComboBox will not cause the application to close, while it will close with the other controls.
import javafx.application.Application;
import javafx.beans.property.SimpleStringProperty;
import javafx.beans.value.ObservableValue;
import javafx.collections.FXCollections;
import javafx.event.EventHandler;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.control.TableColumn.CellDataFeatures;
import javafx.scene.control.cell.TextFieldTableCell;
import javafx.scene.input.KeyEvent;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;
import javafx.util.Callback;
import javafx.util.converter.DefaultStringConverter;
public class FXEventFiltering extends Application {
public static void main(String[] args) { launch(args); }
#Override
public void start(final Stage stage) throws Exception {
//All the controls are added here
VBox box = new VBox();
ComboBox<String> dropdown = new ComboBox<>();
TextField field = new TextField();
CheckBox check = new CheckBox("Check");
RadioButton radio = new RadioButton("Radio!");
TextArea area = new TextArea();
TableView<String> table = new TableView<String>(FXCollections.observableArrayList(new String[]{"one","two"}));
TableColumn<String, String> tc = new TableColumn<String, String>("Column1");
tc.setEditable(true);
tc.setCellFactory(TextFieldTableCell.<String,String>forTableColumn(new DefaultStringConverter()));
tc.setCellValueFactory(new Callback<CellDataFeatures<String,String>, ObservableValue<String>>(){
#Override
public ObservableValue<String> call(CellDataFeatures<String, String> arg0) {
return new SimpleStringProperty(arg0.getValue());
}});
table.getColumns().add(tc);
box.getChildren().addAll(dropdown, field, check, radio, area, table);
//Setting up your scene
Scene scene = new Scene(box);
stage.setScene(scene);
scene.addEventHandler(KeyEvent.ANY, new EventHandler<KeyEvent>() {
#Override
public void handle(KeyEvent event) {
System.out.println("KEYS!" + event.getEventType().getName());
switch (event.getCode()) {
case ESCAPE:
System.out.println("Escape!");
stage.hide();
event.consume();
break;
default:
break;
}
}
});
box.requestFocus(); // Removing default focus
stage.show();
}
}

Maybe you could loop over all nodes after catching the event in the scene to find out which node has actual focus? Then you could call node method to close?