Develop Reference

Trying to stop a single thread out of multiple running at the same time in java

So im trying to stop a single thread when I have multiple threads running, here is the code im using to initialise the threads. Basically I have multiple textFields in javafx, and when a button is clicked on the screen, it fills the textFields, one by one, with an incrementing timer. Now I also have a button for each of the textfields to clear it, but the problem is when I clear it, because the thread is still running, the timer vanishes for a second and comes back because of the line 'orderTimes.get(boxNo).setText(minute + second);' in the code.
Now what I've tried is creating a list of threads and I've tried implementing it below but it doesn't work, this is so I can call each individual thread if its button to clear has been clicked.
Does anyone know how I can close/stop only one single thread out of multiple that are running? If more info is needed just let me know, thanks.
public static void createIncrementingTimer(int boxNo, List<TextField> orderTimes) {
minutesList.set(boxNo, 0);
secondsList.set(boxNo, 0);
state = true;
new Thread(threadList.get(boxNo)) {
int currentMinutes = 0;
int currentSeconds = 0;
public void run() {
for (;;) {
if (state = true) {
try {
sleep(1000);
if (secondsList.get(boxNo) > 59) {
secondsList.set(boxNo, 0);
currentSeconds = 0;
minutesList.set(boxNo, currentMinutes + 1);
currentMinutes++;
}
if (secondsList.get(boxNo) < 10) {
second = ":0" + Integer.toString(secondsList.get(boxNo));
} else {
second = ":" + Integer.toString(secondsList.get(boxNo));
}
secondsList.set(boxNo, currentSeconds + 1);
currentSeconds++;
if (minutesList.get(boxNo) < 10) {
minute = "0" + Integer.toString(minutesList.get(boxNo));
} else {
minute = Integer.toString(minutesList.get(boxNo));
}
orderTimes.get(boxNo).setText(minute + second);
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
};
threadList.get(boxNo).start();
}
The code I'm using to clear the textfields is below, with orderTimes being the list of textFields that I'm trying to clear.
public static void eraseBox(int clickedButtonNumber, List<TextArea> orderContentsList, List<TextField> tableNumbers, List<TextField> orderNumbers, List<TextField> orderTimes) {
orderContentsList.get(clickedButtonNumber).setText(null);
tableNumbers.get(clickedButtonNumber).clear();
orderNumbers.get(clickedButtonNumber).clear();
orderTimes.get(clickedButtonNumber).clear();
}

I would suggest you try to avoid Threads. The Animation API is designed to make doing work that would normally be done in a Thread easier. In this example, the IncrementingTimer class consists of two Labels and three Buttons. The Labels are used to show the time. The Buttons are used to control the Timeline. The Timeline is used to increment the Labels value each second or every sixty seconds. I have added three IncrementingTimers to the app.
Main
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;
/**
* JavaFX App
*/
public class App extends Application {
#Override
public void start(Stage stage) {
var scene = new Scene(new VBox(new IncrementingTimer(), new IncrementingTimer(), new IncrementingTimer()), 640, 480);
stage.setScene(scene);
stage.show();
}
public static void main(String[] args) {
launch();
}
}
IncrementingTimer
import javafx.animation.KeyFrame;
import javafx.animation.Timeline;
import javafx.beans.property.IntegerProperty;
import javafx.beans.property.SimpleIntegerProperty;
import javafx.geometry.Pos;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.layout.HBox;
import javafx.util.Duration;
/**
*
* #author blj0011
*/
final public class IncrementingTimer extends HBox
{
IntegerProperty secondsCounter = new SimpleIntegerProperty();//Keeps up with seconds
IntegerProperty minutesCounter = new SimpleIntegerProperty();//Keeps up with minutes
Label lblSeconds = new Label();//Displays the seconds
Label lblMinutes = new Label();//Displays the minutes
Label lblColon = new Label(":");//Display the colon between minutes and seconds
Button btnPlay = new Button("Play");//Plays the Timeline
Button btnStop = new Button("Stop");//Stops the Timeline
Button btnPause = new Button("Pause");//Pauses the Timeline
Timeline timeline;//Used to run code that changes the Labels. This Timeline runs every one second.
public IncrementingTimer()
{
lblSeconds.textProperty().bind(secondsCounter.asString("%02d"));//Binds the seconds label to the seconds counter. Sets the String to always show two digits. Exmaple 1 is shown as 01.
lblMinutes.textProperty().bind(minutesCounter.asString("%02d"));//Binds the minutes label to the minutes counter. Sets the String to always show two digits. Exmaple 1 is shown as 01.
getChildren().addAll(lblMinutes, lblColon, lblSeconds, btnPlay, btnStop, btnPause);
timeline = new Timeline(new KeyFrame(Duration.seconds(1), (event) -> {//Replace the one with .016 to speed this up for testing purposes.
secondsCounter.set(secondsCounter.get() + 1);
if (secondsCounter.get() == 60) {
secondsCounter.set(0);
minutesCounter.set(minutesCounter.get() + 1);
if (minutesCounter.get() == 60) {
minutesCounter.set(0);
}
}
}));
timeline.setCycleCount(Timeline.INDEFINITE);
btnPlay.setOnAction((event) -> {
timeline.play();
});
btnPause.setOnAction((event) -> {
timeline.pause();
});
btnStop.setOnAction((event) -> {
timeline.stop();
secondsCounter.set(0);
minutesCounter.set(0);
});
this.setAlignment(Pos.CENTER);
}
}

As recommended and demonstrated by Sedric, use JavaFx Animation tools for the counters.
The following one-file mre demonstrating implementation of counters using two different animation tools.
One uses PauseTransition and uses Timeline, each with its stop button.
(copy-paste the entire code into Timers.java and run)
import java.io.IOException;
import javafx.animation.Animation;
import javafx.animation.KeyFrame;
import javafx.animation.PauseTransition;
import javafx.animation.Timeline;
import javafx.application.Application;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.layout.HBox;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;
import javafx.util.Duration;
public class Timers extends Application {
#Override public void start(final Stage stage) throws IOException {
VBox root = new VBox(new CounterPane(new TimeLineCounter()), new CounterPane(new PauseTransitionCounter()));
stage.setScene(new Scene(root));
stage.show();
}
public static void main(final String[] args) { launch(args); }
}
class CounterPane extends HBox{
private final Counter counter;
CounterPane(Counter counter) {
super(5);
this.counter = counter; //todo: check not null
Button stopBtn = new Button("Stop");
stopBtn.setOnAction(e->stop());
getChildren().addAll(stopBtn, counter);
}
void stop(){
counter.getAnimation().stop();
}
}
abstract class Counter extends Label {
protected int count = 0;
public Counter() {
setAlignment(Pos.CENTER); setPrefSize(25, 25);
count();
}
abstract void count();
abstract Animation getAnimation();
}
class TimeLineCounter extends Counter {
private Timeline timeline;
#Override
void count() {
timeline = new Timeline();
timeline.setCycleCount(Animation.INDEFINITE);
final KeyFrame keyFrame = new KeyFrame(
Duration.seconds(1),
event -> { setText(String.valueOf(count++) ); }
);
timeline.getKeyFrames().add(keyFrame);
timeline.play();
}
#Override
Animation getAnimation() {
return timeline;
}
}
class PauseTransitionCounter extends Counter {
private PauseTransition pauseTransition;
#Override
void count() {
pauseTransition = new PauseTransition(Duration.seconds(1));
pauseTransition.setOnFinished(event ->{
setText(String.valueOf(count++) );
pauseTransition.play();
});
pauseTransition.play();
}
#Override
Animation getAnimation() {
return pauseTransition;
}
}

The if(state=true) should rather be if(state==true) or just if(state), but in fact the for(;;) could do the entire thing as while(state), simply shutting down the thread when you set state=false.
Then, fully stopping the thread could happen as state=false;threadList.get(boxNo).join();, and you can clear the field only after that (since the thread will set it to something in the last step too).
With a simpler approach you could throw away the state, and revert to for(;;), with the twist of having the try-catch() around the loop, outside. This way you can use threadList.get(boxNo).interrupt();threadList.get(boxNo);.join(); to stop the thread, and on top of that it will be immediate, as the sleep() ends immediately when the thread is interrupted.

Items replacing but not asked

I'm working on a little game. So I create the game interface (countains the gun, the canvas which I use as gamespace and an interface for the user to control is gun). I place the different elements in the window and there is my problem. When I execute my code, all is well placed but once I use one of the buttons (buttons in both codes) or the slider (second code), the slider and the fire button replace themselves. And I don't understand why because I never asked this rellocation in my code. Also, when the items rellocate, I can't use any other items excepted the fire button and the slider.
Here are screenshots of what I have before using a button (first screenshot) (it's also how I want the interface to be) and the second screenshot shows the rellocation I have.
How it looks when I use nothing.
How it looks when I use a button or the slider.
Main.java :
package application;
import bureaux.Bureau;
import canons.Canon;
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.canvas.Canvas;
import javafx.scene.canvas.GraphicsContext;
import javafx.scene.control.Button;
import javafx.scene.control.ToolBar;
import javafx.scene.image.Image;
import javafx.scene.image.ImageView;
import javafx.scene.layout.FlowPane;
import javafx.scene.layout.StackPane;
import javafx.scene.paint.Color;
import javafx.scene.text.Font;
import javafx.scene.text.Text;
import javafx.stage.Stage;
public class Main extends Application{
private StackPane root, rootBureau;
private Scene scene;
private Stage stage;
private Text joueur;
private Button menu, musique, ajoutJoueur;
private FlowPane rootJeu;
private Bureau bureauJoueur;
private ToolBar toolBar;
private Canon canonJoueur;
#Override
public void start(Stage primaryStage) throws IOException {
getRoot();
getScene();
stage = primaryStage;
creerInterface();
stage.setTitle("Mad Java Guns");
stage.setResizable(false);
stage.setScene(scene);
stage.show();
}
public static void main(String[] args) {
launch(args);
}
public void creerInterface(String mode) { // creating the gamespace and the objects that the user need to play
getToolBar().getItems().addAll(getMusique(), getAjoutJoueur());
getRootBureau().getChildren().add(getBureauJoueur());
getRootJeu().getChildren().add(getCanonJoueur());
getRoot().getChildren().addAll(getToolBar(), getJoueur(), getRootBureau(), getRootJeu());
}
// Getters
public StackPane getRoot() {
if(root == null) {
root = new StackPane();
}
return root;
}
public Scene getScene() {
if(scene == null) {
scene = new Scene(root,1000,800);
}
return scene;
}
public Text getJoueur() { // gamespace
if(joueur == null) {
joueur = new Text("Espace de jeu");
joueur.setFont(Font.font("Arial", 20));
joueur.setTranslateY(120);
}
return joueur;
}
public ToolBar getToolBar() {
if(toolBar == null) {
toolBar = new ToolBar();
toolBar.setTranslateY(122);
toolBar.setTranslateX(3);
toolBar.setStyle("-fx-background-color: transparent");
}
return toolBar;
}
public Button getMusique() { // button too change the music in game
if (musique == null) {
musique = new Button("Musique");
musique.setOnMouseClicked(e -> {
System.out.println("musique"); // not coded yet
});
musique.setFocusTraversable(false);
}
return musique;
}
public Button getAjoutJoueur() { // add players in the game
if(ajoutJoueur == null) {
ajoutJoueur = new Button("Ajouter un joueur");
ajoutJoueur.setOnMouseClicked(e -> {
System.out.println("ajoutJoueur"); //not coded yet
});
ajoutJoueur.setFocusTraversable(false);
}
return ajoutJoueur;
}
public StackPane getRootBureau() { // pane where the user's interface will be placed
if(rootBureau == null) {
rootBureau = new StackPane();
rootBureau.setStyle("-fx-background-color: lightgrey");
rootBureau.setMaxSize(990, 250);
rootBureau.setTranslateY(270);
}
return rootBureau;
}
public Bureau getBureauJoueur() { // user's interface
if(bureauJoueur == null) {
bureauJoueur = new Bureau("Billy", getCanonJoueur());
}
return bureauJoueur;
}
}
Class Bureau.java :
package bureaux;
import canons.Canon;
import javafx.geometry.Orientation;
import javafx.scene.Parent;
import javafx.scene.control.Button;
import javafx.scene.control.Slider;
import javafx.scene.layout.HBox;
import javafx.scene.layout.VBox;
public class Bureau extends Parent {
private Slider sliderCanon;
private HBox boxPrincipale;
private VBox boxControlesCanon;
private Button feu;
public Bureau(String nom, Canon canon) {
getBoxControlesCanon().getChildren().addAll(getSliderCanon(), getFeu());
getBoxPrincipale().getChildren().add(getBoxControlesCanon());
this.setTranslateX(-480); // placing the boxes
this.setTranslateY(-95);
this.getChildren().add(getBoxPrincipale());
}
//Getteurs
public HBox getBoxPrincipale() {
if(boxPrincipale == null) { // return a HBox which countains the VBox (next function)
// and other elements which aren't created yet.
boxPrincipale = new HBox();
}
return boxPrincipale;
}
public VBox getBoxControlesCanon() { // return a VBox which countains the controls of the gun
//(gun not showed in the code, doesn't concern the problem)
if(boxControlesCanon == null) {
boxControlesCanon = new VBox();
boxControlesCanon.setSpacing(20);
}
return boxControlesCanon;
}
public Slider getSliderCanon() { //slider to orient the gun (gun not showed in the code, doesn't concern the problem)
if(sliderCanon == null) {
sliderCanon = new Slider(0, 360, 0);
sliderCanon.setOrientation(Orientation.VERTICAL);
sliderCanon.valueProperty().addListener(e -> {
System.out.println(sliderCanon.getValue());
});
sliderCanon.setShowTickMarks(true);
sliderCanon.setShowTickLabels(true);
sliderCanon.setMajorTickUnit(90f);
}
return sliderCanon;
}
public Button getFeu() { // fire button
if(feu == null) {
feu = new Button("Feu");
feu.setOnMouseClicked(e -> {
System.out.println("Feu");
});
feu.setFocusTraversable(false);
}
return feu;
}
}
Please ask for more informations if necessary. Thanks for your help.
EDIT : sorry for the unpoliteness on top of this text, I used to edit it and add "Hello" but it just don't want to show it :/

You are using Bureau extends Parent. You will have to be more specific and used the nodes that will produce the outcome you need.
Try something like Bureau extends HBox. Then
getBoxControlesCanon().getChildren().add(new VBox(getSliderCanon(), getFeu()));
To get the left alignment, you may need to do something like
getBoxControlesCanon().getChildren().addAll(new VBox(getSliderCanon(), getFeu()), someOtherNode);
HBox.setHGrow(someOtherNode, Priority.ALWAYS);
If you look at Parent compared to VBox, you will see that Parent does not describe how children nodes will be laid out. A lot of nodes that are a subclass of Parent do describe how their children nodes will be laid out.

Synchronize scrollbars of two JavaFx WebViews

I'm using two WebViews to display two versions of HTML formatted text for comparison. The two display the same amount of text (same number of lines and corresponding lines have always the same length).
When the displayed text exceeds the size of the node, the WebView gets scroll bars. Of course I want these scroll bars to scroll synchronously so that always the corresponding text is displayed.
In order to supply a minimal, complete and verifiable example, I trimmed the code down to this:
import javafx.application.Application;
import javafx.application.Platform;
import javafx.geometry.Insets;
import javafx.scene.Scene;
import javafx.scene.control.ScrollBar;
import javafx.scene.layout.GridPane;
import javafx.scene.web.WebView;
import javafx.stage.Stage;
public class SynchronizedWebViewsTest extends Application {
protected class DifferencePanel extends GridPane {
private WebView actualPane;
private WebView expectedPane;
public DifferencePanel() {
setPadding(new Insets(20, 20, 20, 20));
actualPane = new WebView();
expectedPane = new WebView();
setResultPanes();
addRow(0, actualPane, expectedPane);
}
public void setHtml(WebView webView) {
Platform.runLater(() -> {
webView.getEngine().loadContent(createHtml());
});
}
public void synchronizeScrolls() {
final ScrollBar actualScrollBarV = (ScrollBar)actualPane.lookup(".scroll-bar:vertical");
final ScrollBar expectedScrollBarV = (ScrollBar)expectedPane.lookup(".scroll-bar:vertical");
actualScrollBarV.valueProperty().bindBidirectional(expectedScrollBarV.valueProperty());
final ScrollBar actualScrollBarH = (ScrollBar)actualPane.lookup(".scroll-bar:horizontal");
final ScrollBar expectedScrollBarH = (ScrollBar)expectedPane.lookup(".scroll-bar:horizontal");
actualScrollBarH.valueProperty().bindBidirectional(expectedScrollBarH.valueProperty());
}
private String createHtml() {
StringBuilder sb = new StringBuilder(1000000);
for (int i = 0; i < 100; i++) {
sb.append(String.format("<nobr>%03d %2$s%2$s%2$s%2$s%2$s%2$s%2$s%2$s</nobr><br/>\n",
Integer.valueOf(i), "Lorem ipsum dolor sit amet "));
}
return sb.toString();
}
private void setResultPanes() {
setHtml(actualPane);
setHtml(expectedPane);
}
} // ---------------------------- end of DifferencePanel ----------------------------
public static void main(String[] args){
launch(args);
}
#Override
public void start(Stage dummy) throws Exception {
Stage stage = new Stage();
stage.setTitle(this.getClass().getSimpleName());
DifferencePanel differencePanel = new DifferencePanel();
Scene scene = new Scene(differencePanel);
stage.setScene(scene);
differencePanel.synchronizeScrolls();
stage.showAndWait();
}
}
I tried using adding a listener:
actualScrollBarV.onScrollFinishedProperty().addListener(event -> {
System.out.println(event);
});
But the listener is never invoked.
I'm using Java version 1.8.0_92, but with version 9.0.4 I get the same result.
Can anybody tell me, what I'm missing here?

I would post a comment, but sadly I did not have enough reputation.
Did you tried the following solution? Create listeners on value changed event, instead of binding. Synchronizing two scroll bars JavaFX

I could not get the ScrollBar approach working. It turned out that the listeners were actually invoked (breakpoints in lambdas are not always working?). Setting the scroll bar value of the other WebView did not get it inclined change the scroll bar or the view port. :-(
There is something strange going on with events in WebView; that might be because there is a native library involved...
However, the approach using the event handler of WebView works. The event handler of each WebView simply mirrors all events to the other WebView, using a synchronizing field Boolean scrolling to avoid recursion.
import javafx.application.Application;
import javafx.application.Platform;
import javafx.event.Event;
import javafx.geometry.Insets;
import javafx.geometry.Point2D;
import javafx.scene.Scene;
import javafx.scene.input.MouseButton;
import javafx.scene.input.MouseEvent;
import javafx.scene.layout.GridPane;
import javafx.scene.web.WebView;
import javafx.stage.Stage;
public class SynchronizedWebViewsTest extends Application {
protected class DifferencePanel extends GridPane {
private Boolean scrolling = Boolean.FALSE;
private WebView actualPane;
private WebView expectedPane;
public DifferencePanel() {
setPadding(new Insets(20, 20, 20, 20));
actualPane = new WebView();
expectedPane = new WebView();
setResultPanes();
addRow(0, actualPane, expectedPane);
}
public void setHtml(WebView webView) {
Platform.runLater(() -> {
webView.getEngine().loadContent(createHtml());
});
}
public void synchronizeScrolls() {
wireViews(actualPane, expectedPane);
wireViews(expectedPane, actualPane);
}
private void wireViews(WebView webView, WebView otherWebView) {
webView.addEventHandler(Event.ANY, event -> {
if (!scrolling.booleanValue()) {
synchronized (scrolling) {
scrolling = Boolean.TRUE;
if (event instanceof MouseEvent) {
MouseEvent mouseEvent = (MouseEvent) event;
Point2D origin = webView.localToScreen(0, 0);
Point2D otherOrigin = otherWebView.localToScreen(0, 0);
double offsetX = otherOrigin.getX() - origin.getX();
double offsetY = otherOrigin.getY() - origin.getY();
double x = mouseEvent.getX();
double y = mouseEvent.getY();
double screenX = mouseEvent.getScreenX() + offsetX;
double screenY = mouseEvent.getScreenY() + offsetY;
MouseButton button = mouseEvent.getButton();
int clickCount = mouseEvent.getClickCount();
boolean shiftDown = mouseEvent.isShiftDown();
boolean controlDown = mouseEvent.isControlDown();
boolean altDown = mouseEvent.isAltDown();
boolean metaDown = mouseEvent.isMetaDown();
boolean primaryButtonDown = mouseEvent.isPrimaryButtonDown();
boolean middleButtonDown = mouseEvent.isMiddleButtonDown();
boolean secondaryButtonDown = mouseEvent.isSecondaryButtonDown();
boolean synthesized = mouseEvent.isSynthesized();
boolean popupTrigger = mouseEvent.isPopupTrigger();
boolean stillSincePress = mouseEvent.isStillSincePress();
MouseEvent otherMouseEvent =
new MouseEvent(otherWebView, otherWebView, mouseEvent.getEventType(), x, y, screenX,
screenY, button, clickCount, shiftDown, controlDown, altDown, metaDown,
primaryButtonDown, middleButtonDown, secondaryButtonDown, synthesized,
popupTrigger, stillSincePress, null);
otherWebView.fireEvent(otherMouseEvent);
}
else {
otherWebView.fireEvent(event.copyFor(otherWebView, otherWebView));
}
scrolling = Boolean.FALSE;
}
}
});
}
private String createHtml() {
StringBuilder sb = new StringBuilder(1000000);
for (int i = 0; i < 100; i++) {
sb.append(String.format("<nobr>%03d %2$s%2$s%2$s%2$s%2$s%2$s%2$s%2$s</nobr><br/>\n",
Integer.valueOf(i), "Lorem ipsum dolor sit amet "));
}
return sb.toString();
}
private void setResultPanes() {
setHtml(actualPane);
setHtml(expectedPane);
}
}
public static void main(String[] args){
launch(args);
}
#Override
public void start(Stage dummy) throws Exception {
Stage stage = new Stage();
stage.setTitle(this.getClass().getSimpleName());
DifferencePanel differencePanel = new DifferencePanel();
Scene scene = new Scene(differencePanel);
stage.setScene(scene);
differencePanel.synchronizeScrolls();
stage.showAndWait();
}
}
This works for all input methods I'm interested in:
Keyboard: PageUp, PageDown, all 4 arrow keys, "space bar" (same as PageDown) and shift-"space bar" (same as PageUp), Home and End
Mouse wheel: RollDown and RollUp as well as shift-RollUp (scroll left) and shift-RollDown (scroll right)
Using the mouse to click or to drag the scroll bar.
Using the mouse to select text outside of the current view port.
Mirroring the mouse events has the added benefit that text gets selected in both WebViews.

What is right way to work with tableview?

For some time i have been trying to get my tableview work as kind of spreadsheet that is updated by background thread and when cell get updated, it for few seconds higlights ( changes style ) and then goes back to original style.
I already know, that i can't store and set styles directly in table cell and i need some kind of backing class, that will hold this data. But tableview with its "reusing" of cells (using same cells for different data) acts really weird. When all cells fits on screen it works flawlessly for me, but once i place around 100 cells and it becomes scrollable it starts being buggy, sometimes styles ( or setted graphic) disappears and after scrolling appears, if i disable some top cells of view, some other cells after scrolling get disabled as well and so on. Is there any right way to do this?
What i need basically is
Background data thread ---updates--> tableview
Another thread --after few seconds removes style--> tableview
As i have it now, i have model class that holds data, style and reference to table cell where it should be ( i disabled ordering, so it should be ok ) and background thread updates data in model class, and that model class changes style on referenced cell and register itself in "style remover" thread, that after while removes style.
I think posting my actual code won't be useful, because once i've discovered that cells are being reused my code has become too complicated and a little bit unreadable so i want to completely redo it right way.
Peformance is not that important for me, there wont be more than 100 cells, but this highlighting and having buttons in tableview must work flawlessly.
This is how my app looks like now - for idea of what i need.
EDIT: here is link to my another question related to this.

The collaborators:
on the data side, a (view) model which has a recentlyChanged property, that's updated whenever the value is changed
on the view side, a custom cell that listens to that recentlyChanged property and updates its style as appropriate
The tricky part is to clean up cell state when re-used or not-used: the method that's always (hopefully!) called is cell.updateIndex(int newIndex), so that's the place to un-/register the listener.
Below a runnable (though crude ;) example
import java.util.logging.Logger;
import java.util.stream.Collectors;
import java.util.stream.Stream;
import de.swingempire.fx.util.FXUtils;
import javafx.animation.KeyFrame;
import javafx.animation.Timeline;
import javafx.application.Application;
import javafx.beans.property.ReadOnlyBooleanProperty;
import javafx.beans.property.ReadOnlyBooleanWrapper;
import javafx.beans.property.SimpleStringProperty;
import javafx.beans.property.StringProperty;
import javafx.beans.value.ChangeListener;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.TableCell;
import javafx.scene.control.TableColumn;
import javafx.scene.control.TableView;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.HBox;
import javafx.stage.Stage;
import javafx.util.Duration;
public class TableCoreRecentlyChanged extends Application {
public static class RecentChanged extends TableCell<Dummy, String> {
private ChangeListener<Boolean> recentListener = (src, ov, nv) -> updateRecentStyle(nv);
private Dummy lastDummy;
/*
* Just to see any effect.
*/
protected void updateRecentStyle(boolean highlight) {
if (highlight) {
setStyle("-fx-background-color: #99ff99");
} else {
setStyle("-fx-background-color: #009900");
}
}
#Override
public void updateIndex(int index) {
if (lastDummy != null) {
lastDummy.recentlyChangedProperty().removeListener(recentListener);
lastDummy = null;
}
updateRecentStyle(false);
super.updateIndex(index);
if (getTableRow() != null && getTableRow().getItem() != null) {
lastDummy = getTableRow().getItem();
updateRecentStyle(lastDummy.recentlyChangedProperty().get());
lastDummy.recentlyChangedProperty().addListener(recentListener);
}
}
#Override
protected void updateItem(String item, boolean empty) {
if (item == getItem()) return;
super.updateItem(item, empty);
if (item == null) {
super.setText(null);
super.setGraphic(null);
} else {
super.setText(item);
super.setGraphic(null);
}
}
}
private Parent getContent() {
TableView<Dummy> table = new TableView<>(createData(50));
table.setEditable(true);
TableColumn<Dummy, String> column = new TableColumn<>("Value");
column.setCellValueFactory(c -> c.getValue().valueProperty());
column.setCellFactory(e -> new RecentChanged());
column.setMinWidth(200);
table.getColumns().addAll(column);
int editIndex = 20;
Button changeValue = new Button("Edit");
changeValue.setOnAction(e -> {
Dummy dummy = table.getItems().get(editIndex);
dummy.setValue(dummy.getValue()+"x");
});
HBox buttons = new HBox(10, changeValue);
BorderPane content = new BorderPane(table);
content.setBottom(buttons);
return content;
}
private ObservableList<Dummy> createData(int size) {
return FXCollections.observableArrayList(
Stream.generate(Dummy::new)
.limit(size)
.collect(Collectors.toList()));
}
private static class Dummy {
private static int count;
ReadOnlyBooleanWrapper recentlyChanged = new ReadOnlyBooleanWrapper() {
Timeline recentTimer;
#Override
protected void invalidated() {
if (get()) {
if (recentTimer == null) {
recentTimer = new Timeline(new KeyFrame(
Duration.millis(2500),
ae -> set(false)));
}
recentTimer.playFromStart();
} else {
if (recentTimer != null) recentTimer.stop();
}
}
};
StringProperty value = new SimpleStringProperty(this, "value", "initial " + count++) {
#Override
protected void invalidated() {
recentlyChanged.set(true);
}
};
public StringProperty valueProperty() {return value;}
public String getValue() {return valueProperty().get(); }
public void setValue(String text) {valueProperty().set(text); }
public ReadOnlyBooleanProperty recentlyChangedProperty() { return recentlyChanged.getReadOnlyProperty(); }
public String toString() {return "[dummy: " + getValue() + "]";}
}
#Override
public void start(Stage primaryStage) throws Exception {
primaryStage.setScene(new Scene(getContent()));
// primaryStage.setTitle(FXUtils.version());
primaryStage.show();
}
public static void main(String[] args) {
launch(args);
}
#SuppressWarnings("unused")
private static final Logger LOG = Logger
.getLogger(TableCoreRecentlyChanged.class.getName());
}

JavaFX combobox, on item clicked

My problem is as follows,
For the sake of this question I reproduced the problem in a new project.
Say I have this application with a combobox in it, there could be 1 or more items in there. And I would like it to be so that when the user clicks an item in the combobox that 'something' happens.
I produced the following code:
obsvList.add("item1");
cbTest.setOnAction(new EventHandler<ActionEvent>() {
#Override
public void handle(ActionEvent event) {
System.out.println("Item clicked");
}
});
This works when the application starts and an item is selected for the first time. This also works when there are 2 or more items in the combobox (when the user clicks item 1, then item 2, then item 1 for example)
However my problem is that when there is only 1 item in the combobox, let's say "item1". And the user reopens the combobox and clicks "item1" again then it won't redo the action.
It will only print the line "Item Clicked" when a 'new' item is clicked.
I hope it made it clear what the problem i'm experiencing is, if not please ask for clarification and I will give so where needed.
Thanks in advance!

The functionality of a combo box is to present the user with a list of options from which to choose. When you are using a control which implies selection, you should really ensure that the UI is always consistent with the option that is selected. If you do this, then it makes no sense to "repeat an action" when the user "reselects" the same option (because the UI is already in the required state). One approach to this is to use binding or listeners on the combo box's value:
import javafx.application.Application;
import javafx.beans.property.SimpleStringProperty;
import javafx.beans.property.StringProperty;
import javafx.scene.Scene;
import javafx.scene.control.ComboBox;
import javafx.scene.control.Label;
import javafx.scene.layout.BorderPane;
import javafx.stage.Stage;
public class ComboBoxExample extends Application {
#Override
public void start(Stage primaryStage) {
ComboBox<Item> choices = new ComboBox<>();
for (int i = 1 ; i <=3 ; i++) {
choices.getItems().add(new Item("Choice "+i, "These are the details for choice "+i));
}
Label label = new Label();
choices.valueProperty().addListener((obs, oldItem, newItem) -> {
label.textProperty().unbind();
if (newItem == null) {
label.setText("");
} else {
label.textProperty().bind(newItem.detailsProperty());
}
});
BorderPane root = new BorderPane();
root.setCenter(label);
root.setTop(choices);
Scene scene = new Scene(root, 400, 400);
primaryStage.setScene(scene);
primaryStage.show();
}
public class Item {
private final String name ;
private final StringProperty details = new SimpleStringProperty() ;
public Item(String name, String details) {
this.name = name ;
setDetails(details) ;
}
public String getName() {
return name ;
}
#Override
public String toString() {
return getName();
}
public final StringProperty detailsProperty() {
return this.details;
}
public final String getDetails() {
return this.detailsProperty().get();
}
public final void setDetails(final String details) {
this.detailsProperty().set(details);
}
}
public static void main(String[] args) {
launch(args);
}
}
In this case, there is never a need to repeat an action when the user "reselects" the same option, because the code always assures that the UI is consistent with what is selected anyway (there is necessarily nothing to do if the user selects the option that is already selected). By using bindings in the part of the UI showing the details (just a simple label in this case), we are assured that the UI stays up to date if the data changes externally. (Obviously in a real application, this may be far more complex, but the basic strategy is still exactly the same.)
On the other hand, functionality that requires an action to be repeated if the user selects the same functionality is better considered as presenting the user with a set of "actions". The appropriate controls for this are things like menus, toolbars with buttons, and MenuButtons.
An example of a set of repeatable actions is:
import java.util.stream.Collectors;
import java.util.stream.Stream;
import javafx.application.Application;
import javafx.beans.binding.Bindings;
import javafx.beans.property.IntegerProperty;
import javafx.beans.property.SimpleIntegerProperty;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.control.MenuButton;
import javafx.scene.control.MenuItem;
import javafx.scene.layout.BorderPane;
import javafx.stage.Stage;
public class MenuButtonExample extends Application {
#Override
public void start(Stage primaryStage) {
MenuButton menuButton = new MenuButton("Items");
Label label = new Label();
Item[] items = new Item[3];
for (int i = 1 ; i <=3 ; i++) {
items[i-1] = new Item("Item "+i);
}
for (Item item : items) {
MenuItem menuItem = new MenuItem(item.getName());
menuItem.setOnAction(e -> item.setTimesChosen(item.getTimesChosen() + 1));
menuButton.getItems().add(menuItem);
}
label.textProperty().bind(Bindings.createStringBinding(() ->
Stream.of(items)
.map(item -> String.format("%s chosen %d times", item.getName(), item.getTimesChosen()))
.collect(Collectors.joining("\n")),
Stream.of(items)
.map(Item::timesChosenProperty)
.collect(Collectors.toList()).toArray(new IntegerProperty[0])));
BorderPane root = new BorderPane();
root.setCenter(label);
root.setTop(menuButton);
Scene scene = new Scene(root, 400, 400);
primaryStage.setScene(scene);
primaryStage.show();
}
public static class Item {
private final String name ;
private final IntegerProperty timesChosen = new SimpleIntegerProperty();
public Item(String name) {
this.name = name ;
}
public String getName() {
return name ;
}
#Override
public String toString() {
return getName();
}
public final IntegerProperty timesChosenProperty() {
return this.timesChosen;
}
public final int getTimesChosen() {
return this.timesChosenProperty().get();
}
public final void setTimesChosen(final int timesChosen) {
this.timesChosenProperty().set(timesChosen);
}
}
public static void main(String[] args) {
launch(args);
}
}

The idea is to set a listener on the ListView pane, that appears whenever you click on the ComboBox. The ListView instance is created once the ComboBox is first loaded in the JavaFX scene. Therefore, we add a listener on the ComboBox to check when it appears on the scene, and then through the "lookup" method we get the ListView and add a listener to it.
private EventHandler<MouseEvent> cboxMouseEventHandler;
private void initComboBox() {
ComboBox<String> comboBox = new ComboBox<String>();
comboBox.getItems().add("Item 1");
comboBox.getItems().add("Item 2");
comboBox.getItems().add("Item 3");
comboBox.sceneProperty().addListener((a,oldScene,newScene) -> {
if(newScene == null || cboxMouseEventHandler != null)
return;
ListView<?> listView = (ListView<?>) comboBox.lookup(".list-view");
if(listView != null) {
cboxMouseEventHandler = (e) -> {
Platform.runLater(()-> {
String selectedValue = (String) listView.getSelectionModel().getSelectedItem();
if(selectedValue.equals("Item 1"))
System.out.println("Item 1 clicked");
});
}; // cboxMouseEventHandler
listView.addEventFilter(MouseEvent.MOUSE_PRESSED, cboxMouseEventHandler);
} // if
});
} // initComboBox