[FIXED] Platform.runLater and Task in JavaFX

Issue

I have been doing some research on this but I am still VERY confused to say the least.

Can anyone give me a concrete example of when to use Task and when to use Platform.runLater(Runnable);? What exactly is the difference? Is there a golden rule to when to use any of these?

Also correct me if I'm wrong but aren't these two "Objects" a way of creating another thread inside the main thread in a GUI (used for updating the GUI)?

Solution

Use Platform.runLater(...) for quick and simple operations and Task for complex and big operations .

• Use case for Platform.runLater(...)
• Use case for Task: Task Example in Ensemble App

Example: Why Can't we use Platform.runLater(...) for long calculations (Taken from below reference).

Problem: Background thread which just counts from 0 to 1 million and update progress bar in UI.

Code using Platform.runLater(...):

final ProgressBar bar = new ProgressBar();
new Thread(new Runnable() {
    @Override public void run() {
    for (int i = 1; i <= 1000000; i++) {
        final int counter = i;
        Platform.runLater(new Runnable() {
            @Override public void run() {
                bar.setProgress(counter / 1000000.0);
            }
        });
    }
}).start();

This is a hideous hunk of code, a crime against nature (and programming in general). First, you’ll lose brain cells just looking at this double nesting of Runnables. Second, it is going to swamp the event queue with little Runnables — a million of them in fact. Clearly, we needed some API to make it easier to write background workers which then communicate back with the UI.

Code using Task :

Task task = new Task<Void>() {
    @Override public Void call() {
        static final int max = 1000000;
        for (int i = 1; i <= max; i++) {
            updateProgress(i, max);
        }
        return null;
    }
};

ProgressBar bar = new ProgressBar();
bar.progressProperty().bind(task.progressProperty());
new Thread(task).start();

it suffers from none of the flaws exhibited in the previous code

Reference : Worker Threading in JavaFX 2.0

Answered By - invariant
Answer Checked By - Cary Denson (JavaFixing Admin)