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Timer in JavaFX updating Label (Bindings)

I want to add a clock to my application that tells how long you have been doing the task. To simplify it, I have included a counter that increments every second in a new thread and update the label 'setTimer' with the counter number. For this I have a label fx:id="setTimer" in my .fxml file and imported it into my class.
#FXML
private Label setTimer;
And created another class in my class that extends the thread TimerTask and increments the counter by one on each call. Created a new Object 'text', which should always be updated with the current value of the counter.
SimpleStringProperty text = new SimpleStringProperty("undefined");
public class MyTask extends TimerTask {
#Override
public void run() {
counter++;
text.set(Integer.toString(counter));
}
}
To have this class called every second I created a timer in the initialize method and set it to one second.
#Override
public void initialize(URL url, ResourceBundle resourceBundle) {
MyTask myTask = new MyTask();
Timer timer = new Timer(true);
timer.scheduleAtFixedRate(myTask, 0 , 1000);
setTimer.textProperty().bind(text);
}
At the moment I get the exception 'Not on FX application thread; currentThread = Timer-0'.
I've tried many ways to solve my problem, but I haven't gotten to the right point.
My idea of ​​what I want to do should be clear, and I would be happy if someone could help me.
My Problem is to update the changes of the counter in the GUI.
It doesn't have to be solved the way I thought it would, just need a tip on how to best implement it.
Thank you

Ok, my comments are too long. This is how I would try to do it.
Start the stopwatch on the application being loaded
Create a new thread that launches itself every so often.
Inside there, get the time from the Stopwatch in seconds (sw.getTime(TimeUntis.seconds)). Convert that to hours and minutes if you want like shown in this SO post
Then, write the time to the UI using Platform.runLater(new Runnable(){ /* access ui element and write time here */ });

Using Platform.runLater() in a background thread is kind of a messy kludge that should probably be avoided. JavaFX has mechanisms to handle this kind of thing which you should use. Specifically, Task<> is designed to allow background threads to update data which is connected to JavaFX screen elements which need to be updated on the FXAT.
You CAN do what you're trying to do with a JavaFX Task, but using the Java Timer inside of it seems impossible, since there doesn't seem to be any way for a Java thread to wait on a Timer to complete. So, instead I've used a "for" loop with a sleep to do the same thing. It's clumsy, but it does demonstrate how to connect partial results from a Task to screen display:
public class Sample1 extends Application {
public static void main(String[] args) {
launch(args);
}
#Override
public void start(Stage primaryStage) {
Scene scene = new Scene(new Timer1(), 300, 200);
primaryStage.setScene(scene);
primaryStage.show();
}
}
public class Timer1 extends VBox {
public Timer1() {
Text time = new Text();
Button startButton = new Button("Start");
Button stopButton = new Button("Stop");
getChildren().addAll(time, startButton, stopButton);
startButton.setOnAction(startEvt -> {
Task<Integer> timerFxTask = new Task<>() {
{
updateValue(0);
}
#Override
protected Integer call() throws Exception {
for (int counter = 0; counter <= 1000; counter++) {
sleep(1000);
updateValue(counter);
}
return 1000;
}
};
stopButton.setOnAction(stopEvt -> timerFxTask.cancel());
time.textProperty().bind(Bindings.createStringBinding(() -> timerFxTask.getValue().toString(),
timerFxTask.valueProperty()));
Thread timerThread = new Thread(timerFxTask);
timerThread.start();
});
}
}
But there is a better way to do what you're trying to do, which is essentially an animation - and JavaFX has a facility to do exactly this. Usually, people use animations to morph the appearance of JavaFX screen elements, but you can also use it to animate the contents of a Text over time as well. What I've done here is create an IntegerProperty which can be transitioned from a start value to an end value interpolated linearly over time and then bound that value to the TextProperty of a Text on the screen. So you see it update once per second.
public class Sample1 extends Application {
public static void main(String[] args) {
launch(args);
}
#Override
public void start(Stage primaryStage) {
Scene scene = new Scene(new Timer2(), 300, 200);
primaryStage.setScene(scene);
primaryStage.show();
}
}
public class Timer2 extends VBox {
public Timer2() {
Text time = new Text();
Button startButton = new Button("Start");
Button stopButton = new Button("Stop");
getChildren().addAll(time, startButton, stopButton);
startButton.setOnAction(startEvt -> {
IntegerProperty counter = new SimpleIntegerProperty(0);
Timeline timeline = new Timeline(new KeyFrame(Duration.seconds(1000), new KeyValue(counter, 1000)));
stopButton.setOnAction(stopEvt -> timeline.stop());
time.textProperty().bind(Bindings.createStringBinding(() -> Integer.toString(counter.get()), counter));
timeline.play();
});
}
}

Updating ProgressBar through thread in javaFX

I am working on a Java project that makes use of JavaFX's ProgressBar. From what I found on StackOverflow, usually a thread needs to be added, or the program needs to implement Runnable, in order to update the ProgressBar's value dynamically, say when program is running in for loop.
However, looking at java doc and answers in stackoverflow, I am still not sure how, or what is the best way to solve my issue.
Since I have completely no knowledge on JavaFX, can anyone please provide me some hint?
Below is the Application.java as given from the project
public class MyApplication extends Application {
private static final String UI_FILE = "/ui.fxml";
#Override
public void start(Stage stage) throws Exception {
FXMLLoader loader = new FXMLLoader();
loader.setLocation(getClass().getResource(UI_FILE));
VBox root = (VBox) loader.load();
Scene scene = new Scene(root);
stage.setScene(scene);
stage.setTitle("Team T-03: Course Scraper");
stage.show();
}
public static void main(String args[]) {
Application.launch(args);
}
}
The Controller.java that I should implement the related loops and methods
public class Controller {
#FXML
private ProgressBar progressbar;
#FXML
void doSomething() {
for (String object : objectList) {
List<someObject> v = someOtherFunc(object);
totalObjectCount += v.size();
progress = (double) ++objectCount / v.size();
progressbar.setProgress(progress);
}
}
}

Use a Task,
and run it in a new Thread. A Task has its own progress property, and an updateProgress method that ensures the change to the progress is executed on the FX Application Thread. You can then bind your progress bar's progress to the task's:
#FXML
void doSomething() {
Task<Void> task = new Task<>() {
#Override
public Void call() {
for (String object : objectList) {
List<someObject> v = someOtherFunc(object);
totalObjectCount += v.size();
updateProgress(++objectCount, objectList.size());
}
return null ;
}
}
progressBar.progressProperty().bind(task.progressProperty());
new Thread(task).start();
}

How to detect key event in diapason of time JavaFX

I'm making simple space craft game. I have a player (space ship) that fires rockets. When the space button is pressed the player launches a rocket. The problem is that when I hold "space", rockets are launched continuously. How can I prevent this effect and make pressing the space button detected only every 2 seconds, for example (and launch only one rocket)?

You possibly could try to create a list where pressed keys gonna be stored. After pressing the button listener will add that button to list, and will start to count time of pressure. Not sure if is this the best way, but I know, that the same procedure used when developer want to handle few pressed key at once.

You can store in your Ship class whether it is ready to fire a rocket and then in the method which fires the rocket, check for this member.
On rocket launch set this member to false and then you can start a Timeline for example which will reset the flag as it finishes.
Ship class
public class Ship {
private boolean readyToFireRocket = true;
private static final double ROCKET_LAUNCHING_DELAY = 2d;
public void fireRocket() {
if(readyToFireRocket) {
readyToFireRocket = false;
System.out.println("Rocket is fired");
KeyFrame keyFrame = new KeyFrame(Duration.seconds(ROCKET_LAUNCHING_DELAY),
e -> readyToFireRocket = true);
Timeline reloadRockets = new Timeline(keyFrame);
reloadRockets .play();
}
}
}
An example Application
public class Main extends Application {
#Override
public void start(Stage primaryStage) throws Exception{
Parent root = new BorderPane();
Ship ship = new Ship();
Scene scene = new Scene(root, 300, 275);
scene.setOnKeyPressed(e -> {
if(e.getCode() == KeyCode.SPACE) {
ship.fireRocket();
}
});
primaryStage.setScene(scene);
primaryStage.show();
}
public static void main(String[] args) {
launch(args);
}
}

One option is to deregister the event handler for a duration of 2 seconds whenever it is used (and re-register it at the end of the duration). I assume that you are using a setOnKeyPressed(e -> ...) to register the handler that reacts to pressing space.
Create and hold a reference to that handler so you can register and deregister it at will.
Create a PauseTransition with a delay of 2 seconds that registers the above handler when it's done (doing nothing).
In the handle() method, deregister the handler and start the transition.
Here is an example:
public class FXExmple extends Application{
private Button button = new Button("PRESS SPACE");
private PauseTransition pt = new PauseTransition(Duration.seconds(2));
#Override
public void start(Stage stage) throws Exception {
MyEventHandler eh = new MyEventHandler();
pt.setOnFinished(e -> button.setOnKeyPressed(eh));
button.setOnKeyPressed(eh);
Pane pane = new Pane();
pane.getChildren().add(button);
Scene scene = new Scene(pane);
stage.setScene(scene);
stage.sizeToScene();
stage.show();
}
private class MyEventHandler implements EventHandler<KeyEvent> {
#Override
public void handle(KeyEvent event) {
System.out.println("FIRED");
button.setOnKeyPressed(null);
pt.play();
}
}
public static void main(String[] args) {
launch(args);
}
}
Note that this won't give you fine control over the duration since there is duration associated with (de)registering the handler and starting the transition, but they are very small. There is also a limit for the frequency in which the OS sends the events, so if you are planning to go down to ~50ms delays - beware.

How to restart a JavaFX application when a button is clicked

I went through almost every post here regarding the matter but most of them doesn't explain what to do properly.
To the question:
I created a javaFX application, a dice game, human player vs. computer, but during any time while playing the game human player should be able to click button "new game" and what it should do is to restart the game from beginning.
I tried relaunching the stage again but in javafx we cannot call the launch method twice.
1)Is there a way i can implement this without restarting the whole application?
2)if not how can i restart the application completely using a button click?
Main class
public class Main {
public static void main(String[] args) {
GameUI gameUI = new GameUI();
gameUI.launch(GameUI.class, args);
}
GameUI
(i removed many codes from this class to make it short. codes that i think enough to give an idea is included. sorry if it is too long.)
public class GameUI extends Application {
//all btn and label declarations
//creating instances for necessary classes
private Scene scene;
#Override
public void start(Stage primaryStage) throws Exception {
//Displaying Dice for Player and Computer
setLabelsPlyr(diesP);
setLabels(diesC);
btnThrow = new Button("Throw");
btnThrow.setPrefSize(70, 40);
//Throw action is performed
btnThrow.setOnAction(e -> {
//setting and displaying dies
DieClass[] com = getNewDiceArrC();
lblDiceOneC.setGraphic(new ImageView(diesC[0].getDieImageC()));
//so on.....
DieClass[] playerAr = getNewDiceArrP();
lblDiceOnePlyr.setGraphic(new ImageView(diesP[0].getDieImageP()));
//so on...
});
btnNewGame = new Button("New Game");
btnNewGame.setOnAction(e -> {
**//WHAT TO DO HERE?????**
});
//setting layouts
GridPane gridPane = new GridPane();
gridPane.add(lblComputer, 0, 0);
//so on.....
Scene scene = new Scene(gridPane, 1100, 400);
primaryStage.setScene(scene);
primaryStage.setTitle("dice Game");
primaryStage.show();
}
//some other methods
public void setLabels(DieClass[] dies) {
for (int i=0; i < dies.length; i++) {
lblDiceOneC = new Label();
lblDiceOneC.setGraphic(new ImageView(dies[0].getDieImageC()));
++i;
//so on.....
break;
}
}
public void setLabelsPlyr(DieClass[] dies){
for (int i=0; i<dies.length; i++) {
lblDiceOnePlyr = new Label();
lblDiceOnePlyr.setGraphic(new ImageView(dies[0].getDieImageP()));
++i;
lblDiceTwoPlyr = new Label();
//so on......
break;
}
}
p.s I am very new to JavaFX and somewhat new to java programming.

You already noticed that you cannot do the launching process again. Therefore your best option is to rewrite the application class and move the initialisation logic to a new method:
void cleanup() {
// stop animations reset model ect.
}
void startGame(Stage stage) {
// initialisation from start method goes here
btnNewGame.setOnAction(e -> {
restart(stage);
});
stage.show();
}
void restart(Stage stage) {
cleanup();
startGame(stage);
}
#Override
public void start(Stage primaryStage) {
startGame(primaryStage);
}
Notes
Depending on the parts of the scene changed, it may be enough to change the state of some of the nodes (more efficient than creating a new scene). (Just take a look at the changes you made during the game and decide for yourself)
launch() is a static method and you should not create a instance of your application class yourself for that reason. Use Application.launch(GameUI.class, args); instead and let the method handle the creation of the GameUI instance.
It may be a better design to move the UI creation to a class different to the application class. This way reuse of the code is easier, since it does not require the creation of a instance of a subclass of Application.

In your Start() function, add the following line:
Platform.setImplicitExit(false);
This will make your application run in background without exiting.
Now, use a wrapper function to start the second time, say:
void displayApplication() {
Platform.runLater(new Runnable() {
#Override
public void run() {
try {
start(new Stage());
} catch (Exception e) {
e.printStackTrace();
}
}
});
}

Is it possible to make JavaFX web applet?

I like old Java applets. But because I really like the way JFX works, I want write some games using it (or even game making system, who knows?), but I'd like to be able to post them on my website. How would one go about doing this?

Yes, you can embed a JavaFX GUI into the Swing-based JApplet. You can do this by using the JFXPanel - it is essentially an adaptor between Swing and JavaFX panels.
Complete example:
The FXApplet class that sets-up the JavaFX GUI:
public class FXApplet extends JApplet {
protected Scene scene;
protected Group root;
#Override
public final void init() { // This method is invoked when applet is loaded
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
initSwing();
}
});
}
private void initSwing() { // This method is invoked on Swing thread
final JFXPanel fxPanel = new JFXPanel();
add(fxPanel);
Platform.runLater(new Runnable() {
#Override
public void run() {
initFX(fxPanel);
initApplet();
}
});
}
private void initFX(JFXPanel fxPanel) { // This method is invoked on JavaFX thread
root = new Group();
scene = new Scene(root);
fxPanel.setScene(scene);
}
public void initApplet() {
// Add custom initialization code here
}
}
And a test implementation for it:
public class MyFXApplet extends FXApplet {
// protected fields scene & root are available
#Override
public void initApplet() {
// this method is called once applet has been loaded & JavaFX has been set-up
Label label = new Label("Hello World!");
root.getChildren().add(label);
Rectangle r = new Rectangle(25,25,250,250);
r.setFill(Color.BLUE);
root.getChildren().add(r);
}
}
Alternatively, you can use the FXApplet gist, which also includes some documentation.

Yes, you should be able to embed JavaFX in your web page:
http://docs.oracle.com/javase/8/docs/technotes/guides/deploy/deployment_toolkit.html#BABJHEJA
http://docs.oracle.com/javase/8/javase-clienttechnologies.htm