Question

I want to stop Timer at some point and then resume it from the point it was paused at. Methods stop(), start() won’t work.

Is there function for pausing Timer and then resuming it? I guess it doesn’t exist.

Does anyone have an idea how to achieve proper Timer pausing?

Answer 1

javax.swing.Timer.setDelay(int);

import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import java.util.*;
import javax.swing.*;

public class DelayedPaint {

    private CenterPanel center;
    private JFrame frame;
    private JPanel panel;

    public static void main(String args[]) {
        EventQueue.invokeLater(new Runnable() {

            @Override
            public void run() {
                new DelayedPaint().createAndShowGUI();
            }
        });
    }

    void createAndShowGUI() {
        frame = new JFrame("Delayed Paint");
        frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        frame.setSize(400, 400);
        panel = new JPanel(new BorderLayout());
        frame.setContentPane(panel);
        NorthPanel north = new NorthPanel();
        panel.add(north, BorderLayout.NORTH);
        center = new CenterPanel();
        panel.add(center, BorderLayout.CENTER);
        frame.setVisible(true);
        north.startTimer();
    }

    class NorthPanel extends JPanel {

        private JLabel lb;

        public NorthPanel() {
            lb = new JLabel("Good morning");
            add(lb);
        }

        public void startTimer() {
            ActionListener taskPerformer = new ActionListener() {

                @Override
                public void actionPerformed(ActionEvent evt) {
                    setLayout(new FlowLayout(FlowLayout.LEFT));
                    lb.setText("Left");
//    timer.stop(); // Not needed if setRepeats(false).
                    center.startTimer();
                }
            };
            javax.swing.Timer timer = new javax.swing.Timer(2000, taskPerformer);
            timer.setRepeats(false);
            timer.start();
        }
    }

    class CenterPanel extends JPanel {

        private int icnt;
        private Font boldFont = new Font("Dialog", Font.BOLD, 15);
        private Properties centerProps;
        private javax.swing.Timer timer;

        public CenterPanel() {
            centerProps = new Properties();
            centerProps.setProperty("circle", "false");
            centerProps.setProperty("lastString", "0");
        }

        @Override
        public void paintComponent(Graphics g) {
            super.paintComponent(g);
            Graphics2D g2 = (Graphics2D) g;
            if (Boolean.valueOf(centerProps.getProperty("circle"))) {
                Dimension dim = frame.getSize();
                g2.draw(new Arc2D.Double(50, 25, dim.height - 100, dim.width - 100, 0, 360, Arc2D.OPEN));
            }
            int j = Integer.parseInt(centerProps.getProperty("lastString"));
            if (j > 0) {
                g2.setFont(boldFont);
                for (int i = 1; i <= j; i++) {
                    g2.drawString("" + (char) (i + 48), i * 10, 50);
                }
            }
        }

        public void startTimer() {
            ActionListener taskPerformer = new ActionListener() {

                @Override
                public void actionPerformed(ActionEvent evt) {
                    repaint(); // in paintComponent(...) icnt is already icnt+1.
                    icnt++;
                    if (icnt == 1) {
                        centerProps.setProperty("circle", "true");
                        timer.setDelay(500);
                    } else if (icnt <= 10) {
                        centerProps.setProperty("lastString", String.valueOf(icnt - 1));
                        if (icnt == 10) {
                            timer.stop();
                        }
                    }
                }
            };
            timer = new javax.swing.Timer(2000, taskPerformer);
            timer.start();
        }
    }
}