Java graphics not updating correctly

Question

In my program, a the graphics on my screen are supposed to move across the screen. I have a loop that calls the draw function(the draw function is display.draw()), but whenever the amount of times the loop runs is greater than one, the display doesn't update after each time like it should. Instead, it waits until the loop finishes to update the display.

below is the refreshing function that only apparently runs at the end.

public void refresh()
{
    myPanel.removeAll();
    myPanel.add(display.draw());
    myPanel.validate();
    myPanel.repaint();
}

And here's the loop. I added a 1 second sleep after each iteration to make sure it just wasn't moving faster than I could see.

for(int i = 0; i < 2; i++)
{
    myGraphics.rearrange();
    this.refresh();
    try {
        Thread.sleep(1000);
    } catch(InterruptedException e) {
    }
}

myGraphics.rearrange() simply changes the values of the variables which the drawing function uses, changing the x and y variables for the positions of all the objects.

What is happening that it's not updating?

This gets asked all the time... you're blocking the event dispatch thread (that's where the drawing would happen, if it could). Use a swing Timer instead. — kiheru
– kiheru, Commented Dec 2, 2014 at 20:46

Community · Accepted Answer · 2017-05-23 11:51:50Z

4

You're calling Thread.sleep(...) in a Swing program on the Swing event thread. What this does is put the entire application to sleep and so is not something that you should be doing. Instead use a Swing Timer to drive your animation.

For example:

For more specific help, consider posting more code, preferably an mcve.

edited May 23, 2017 at 11:51

CommunityBot

11 silver badge

answered Dec 2, 2014 at 20:47

Hovercraft Full Of Eels

286k25 gold badges268 silver badges391 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Java graphics not updating correctly

1 Answer 1

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related