Concurrency loop not updating Label [duplicate] - javafx

Question

I am building currently an application using JavaFx with an extra feature that displays the current date and time in the top corner of the scene. Since I am new to JavaFX, I don't know how to implement this one.
I tried to use an old code in swing but I got an IllegalStateException Error.
Here's my code.
MainMenuController.java
#FXML private Label time;
private int minute;
private int hour;
private int second;
#FXML
public void initialize() {
Thread clock = new Thread() {
public void run() {
for (;;) {
DateFormat dateFormat = new SimpleDateFormat("hh:mm a");
Calendar cal = Calendar.getInstance();
second = cal.get(Calendar.SECOND);
minute = cal.get(Calendar.MINUTE);
hour = cal.get(Calendar.HOUR);
//System.out.println(hour + ":" + (minute) + ":" + second);
time.setText(hour + ":" + (minute) + ":" + second);
try {
sleep(1000);
} catch (InterruptedException ex) {
//...
}
}
}
};
clock.start();
}
MainMenu.fxml
<children>
<Label fx:id="time" textFill="WHITE">
<font>
<Font name="Segoe UI Black" size="27.0" />
</font>
</Label>
<Label fx:id="date" textFill="WHITE">
<font>
<Font name="Segoe UI Semibold" size="19.0" />
</font>
</Label>
</children>
Main.java
public class Main extends Application {
public static void main(String[] args) {
launch(args);
}
#Override
public void start(Stage primaryStage) throws Exception {
Parent root = FXMLLoader.load(getClass().getResource("view/MainMenu.fxml"));
primaryStage.setScene(new Scene(root,1366, 768));
primaryStage.show();
}
}
As you notice, I tested it printing the live time in the console. Yeah it worked, but the label is still static.

Answer 1

I think you need FX UI Thread Platform.runLater(...) for that, but you can do something like this using Timeline in you controller class,
#FXML
public void initialize() {
Timeline clock = new Timeline(new KeyFrame(Duration.ZERO, e ->
time.setText(LocalDateTime.now().format(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")))
),
new KeyFrame(Duration.seconds(1))
);
clock.setCycleCount(Animation.INDEFINITE);
clock.play();
}
Alternative solution using AnimationTimer - suggested by #James_D,
AnimationTimer timer = new AnimationTimer() {
#Override
public void handle(long now) {
time.setText(LocalDateTime.now().format(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")));
}
};
timer.start();
The second approach using AnimationTimer seems much cleaner and more accurate than with Timeline.
You can check the POC of both approaches here.

Answer 2

The #Shekhar Rai answer works well, but here is a shorter version who works pretty well too.
#FXML
Label dateTime;
#Override
public void initialize(URL location, ResourceBundle resources) {
initClock();
}
private void initClock() {
Timeline clock = new Timeline(new KeyFrame(Duration.ZERO, e -> {
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
dateTime.setText(LocalDateTime.now().format(formatter));
}), new KeyFrame(Duration.seconds(1)));
clock.setCycleCount(Animation.INDEFINITE);
clock.play();
}
The main advantage is that you dont have to define every variables (seconds, minutes, ...)

Answer 3

i have a simple method it may helps you
private JFXDatePicker txtDateVenteAV;
txtDateVenteAV.setValue(LocalDate.now());