Thread accuracy: Swing and threads : Swing Thread « Threads « Java

1. Java
2. Threads
3. Swing Thread

Thread accuracy: Swing and threads

  

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.text.DecimalFormat;

import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.border.EmptyBorder;

public class SecondCounterMain extends JPanel {
  private SecondCounter sc = new SecondCounter();

  private JButton startB = new JButton("Start");

  private JButton stopB = new JButton("Stop");

  public SecondCounterMain() {
    stopB.setEnabled(false); 
    startB.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent e) {
        startB.setEnabled(false);

        Thread counterThread = new Thread(sc, "Counter");
        counterThread.start();

        stopB.setEnabled(true);
        stopB.requestFocus();
      }
    });

    stopB.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent e) {
        stopB.setEnabled(false);
        sc.stopClock();
        startB.setEnabled(true);
        startB.requestFocus();
      }
    });

    JPanel innerButtonP = new JPanel();
    innerButtonP.setLayout(new GridLayout(0, 1, 0, 3));
    innerButtonP.add(startB);
    innerButtonP.add(stopB);

    JPanel buttonP = new JPanel();
    buttonP.setLayout(new BorderLayout());
    buttonP.add(innerButtonP, BorderLayout.NORTH);

    this.setLayout(new BorderLayout(10, 10));
    this.setBorder(new EmptyBorder(20, 20, 20, 20));
    this.add(buttonP, BorderLayout.WEST);
    this.add(sc, BorderLayout.CENTER);
  }

  public static void main(String[] args) {
    SecondCounterMain scm = new SecondCounterMain();

    JFrame f = new JFrame("Second Counter");
    f.setContentPane(scm);
    f.setSize(320, 200);
    f.setVisible(true);
    f.addWindowListener(new WindowAdapter() {
      public void windowClosing(WindowEvent e) {
        System.exit(0);
      }
    });
  }

  class SecondCounter extends JComponent implements Runnable {
    private volatile boolean keepRunning;

    private Font paintFont = new Font("SansSerif", Font.BOLD, 14);

    private volatile String timeMsg = "never started";

    private volatile int arcLen = 0;

    public SecondCounter() {
    }

    public void run() {
      runClock();
    }

    public void runClock() {
      DecimalFormat fmt = new DecimalFormat("0.000");
      long normalSleepTime = 100;
      long nextSleepTime = normalSleepTime;

      int counter = 0;
      long startTime = System.currentTimeMillis();
      keepRunning = true;

      while (keepRunning) {
        try {
          Thread.sleep(nextSleepTime);
        } catch (InterruptedException x) {
          // ignore
        }

        counter++;
        double counterSecs = counter / 10.0;
        double elapsedSecs = (System.currentTimeMillis() - startTime) / 1000.0;

        double diffSecs = counterSecs - elapsedSecs;

        nextSleepTime = normalSleepTime + ((long) (diffSecs * 1000.0));

        if (nextSleepTime < 0) {
          nextSleepTime = 0;
        }

        timeMsg = fmt.format(counterSecs) + " - "
            + fmt.format(elapsedSecs) + " = "
            + fmt.format(diffSecs);

        arcLen = (((int) counterSecs) % 60) * 360 / 60;
        repaint();
      }
    }

    public void stopClock() {
      keepRunning = false;
    }

    public void paint(Graphics g) {
      g.setColor(Color.black);
      g.setFont(paintFont);
      g.drawString(timeMsg, 0, 15);

      g.fillOval(0, 20, 100, 100); // black border

      g.setColor(Color.white);
      g.fillOval(3, 23, 94, 94); // white for unused portion

      g.setColor(Color.blue); // blue for used portion
      g.fillArc(2, 22, 96, 96, 90, -arcLen);
    }
  }
}

           
         
    
  

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