How to use PauseTransition method in JavaFX?

Question

I read the book, but I am still confused about pause transition methods. I made a label showing number, and I want that number to be increased in every second.

Answer 1

How to use a PauseTransition

A PauseTransition is for a one off pause. The following sample will update the text of a label after a one second pause:

label.setText("Started");
PauseTransition pause = new PauseTransition(Duration.seconds(1));
pause.setOnFinished(event ->
   label.setText("Finished: 1 second elapsed");
);
pause.play();

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Why a PauseTransition may not be the best answer for you

According to your question, you want to update the label every second, not just once.

You can run a PauseTransition repetitively, see c0der’s answer. This involves replaying the transition within the handler.

You should use a Timeline

This is my preferred solution for repetitive execution on the JavaFX thread.

As suggested by Tomas Mikula, use a Timeline instead of a PauseTransition.

label.setText("Started");
final IntegerProperty i = new SimpleIntegerProperty(0);
Timeline timeline = new Timeline(
    new KeyFrame(
        Duration.seconds(1),
        event -> {
            i.set(i.get() + 1);
            label.setText("Elapsed time: " + i.get() + " seconds");
        } 
    )
);
timeline.setCycleCount(Animation.INDEFINITE);
timeline.play();

Alternate solution with a Timer

There is an alternate solution based on a Timer for the following question:

• How to update the label box every 2 seconds in java fx?

However, I prefer the Timeline based solution to the Timer solution from that question. The Timer requires a new thread and extra care in ensuring updates occur on the JavaFX application thread. The Timeline based solution does not require any of that.

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Not a solution: setting cycleCount on a pause transition

pauseTransition.setCycleCount(Animation.INDEFINITE) won’t work. With this, the pause transition will cycle indefinitely. That won’t help you, because you can't set an event handler on cycle completion in JavaFX 17.

If a PauseTransition is cycled indefinitely, the finish handler for the transition will never be called because the transition will never finish.

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Related

• Delayed and periodic tasks with JavaFX.

Answer 2

As commented by Adowarth :

you can use the PauseTransition if you start it again inside of the finish handler

int cycle = 0;
label.setText("Started");
PauseTransition pause = new PauseTransition(Duration.seconds(1));
pause.setOnFinished(event ->
   label.setText("Finished cycle " + cycle++);
   pause.play(); 
);
pause.play();