Wsrtjtyk

I want to pause the execution of a Swing Program for a specified amount of time. Naturally the first thing that I used was Thread.sleep(100) (since, I am a noob). Then I got to know that my program is not thread safe so I decided to use Timer with some suggestions from fellow programmers. The problem is I am unable to get any sources from where I can learn how to delay the thread, using Timer. Most of them use Timer for delaying execution. Please help me solve this problem. I have provided a compileable code snippet below.

import javax.swing.*;

import java.awt.*;



public class MatrixBoard_swing extends JFrame{



    public static void main(String args){

        SwingUtilities.invokeLater(new Runnable() {

          public void run() {

            MatrixBoard_swing b = new MatrixBoard_swing();      

          }

       });

    }



    MatrixBoard_swing(){

        this.setSize(640, 480);

        this.setVisible(true);

        while(rad < 200){

            repaint();

            rad++;

            try {

                Thread.sleep(100);

            } catch (InterruptedException e) {

                // TODO Auto-generated catch block

                e.printStackTrace();

            }



        }

    }



    int rad = 10;



    public void paint(Graphics g){

        super.paint(g);

        g.drawOval(400-rad, 400-rad, rad, rad); 

    }



}

EDIT: My trial for a Timer implementation(please tell me if it is wrong):

import javax.swing.*;

import java.awt.*;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;



public class MatrixBoard_swing extends JFrame implements ActionListener{



    Timer timer;



    public static void main(String args){

        SwingUtilities.invokeLater(new Runnable() {

          public void run() {

            MatrixBoard_swing b = new MatrixBoard_swing();      

          }

       });

    }



    MatrixBoard_swing(){

        this.setSize(640, 480);

        this.setVisible(true);

        timer = new Timer(100, this);

        timer.start();

    }



    int rad = 10;



    public void paint(Graphics g){

        super.paint(g);

        g.drawOval(400-rad, 400-rad, rad, rad); 

    }



    @Override

    public void actionPerformed(ActionEvent arg0) {

        repaint();

        rad++;

        if(rad >= 200){

            timer.stop();

        }

    }

So instead of...

while(rad < 200){

    repaint();

    rad++;

    try {

        Thread.sleep(100);

    } catch (InterruptedException e) {

        // TODO Auto-generated catch block

        e.printStackTrace();

    }

}

You simply need to turn the logic around a little...

Timer timer = new Timer(1000, new ActionListener() {

    public void actionPerformed(ActionEvent evt) {

        rad++;

        if (rad < 200) {

            repaint();

        } else {

            ((Timer)evt.getSource()).stop();

        }

    }

});

timer.start();

Basically, the Timer will act as the Thread.sleep(), but in a nice way that doesn't break the UI, but will allow you to inject a delay between execution. Each time it executes, you need to increment your value, test for the "stop" condition and update otherwise...

Take a look at How to Use Swing Timers and the other 3, 800 questions on the subject on SO...