JSlider freezes program

Question

I currently am developing a program that will send a value between 100 and 355 to a serial port with an Arduino connected with rgb led strips.

The program works fine for a little bit but then suddenly freezes and I cannot move any sliders or click on any of the buttons.

I believe this is due to the program processing too many events because if I move the sliders slowly this problem does not happen as frequently but I do not know how to decrease the amount of events activated by the slider.

Here is My Code for a slider:

redslide.addChangeListener(new ChangeListener() {
    public void stateChanged(ChangeEvent arg0) {
        try {
            output.flush();
        } catch (IOException e1) {
            e1.printStackTrace();
        }
        int brightness = redslide.getValue();
        String message = "r" + brightness;
        byte[] data = message.getBytes();
        try {
            output.write(data);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
});

here Is my new code:

redslide.addChangeListener(new ChangeListener() {
    public void stateChanged(ChangeEvent arg0) {
        int brightness = redslide.getValue();
        String message = "r" + brightness;
        byte[] data = message.getBytes();
        new Thread(() -> Write(data)).start();
    }
});

public static void Write(byte[] data){
        try {
            output.write(data);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

Answer 1

It's hard to say for sure without your full program, but it appears you are reading and writing data from the ChangeListener.

The read and write operation block for an indeterminate amount of time, during which the Event Dispatch Thread (EDT) cannot process additional events. Blocking the EDT will make your GUI appear to be frozen.

Try spinning off another thread to handle the read/write operation or use a SwingWorker to avoid blocking the EDT.

(Update your post with the a Minimal, Complete, and Verifiable example and I'll try to give you some more specific guidance)