Question

This is just an exercise in mechanics. I am attempting to create three custom panels that control their own progress bar. It’s part of a time management program I am writing for myself to learn more about Java. The larger program uses dates input by the user to create the framework for the min/max of the progress bar. Both this program and the larger one exhibit the same behavior with multiple bars racing the clock.

The issue I am having is that if I have just one bar everything seems to work just fine, but when I have more than one everything seems to go bust. So I wrote this little program to test some things out. It’s very simple, takes three custom panels, gives them a label and uses a timer event to change the label and the position of the progress bar. My question is If the math lines up (System output shows the calculation) and I’m counting events every second (1000 milliseconds) why is everything beating the count down.

Please forgive my lack of form with my code. I’m more concerned with the logic than the form.

(Most of the below is cut from my larger program, so if you see extraneous bits they really do have a home)
Thank you in advance.

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

public class plaything extends JFrame implements ActionListener
{
myPanel[] mp = new myPanel[3];
JLabel[] jl = new JLabel[3];
short[] tim = new short[3];
short x = 0;
short t = 0; //used to stagger the clocks
short dateSaver; //holds temp dates

public plaything()
{
    setSize(400, 350);
  setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setLayout(new GridLayout(3, 1) ); 

    for(short x = 0; x < 3; x++)
    {
        mp[x] = new myPanel();

        //sets all three bars to different 'times'
        dateSaver = (short)(10 + t) ;
        tim[x] = dateSaver;
        mp[x].setMax( dateSaver );

        jl[x] = new JLabel("Expires: " + dateSaver);
        this.add(mp[x]);
        mp[x].add( jl[x] );
        t += 15; // 15 seconds
    }

    Timer time = new Timer(1000, this);
    time.start();
}
public void actionPerformed(ActionEvent e)
{
    if ( x < 60 )
    {
        x++;
    } 
    else
    {
        x = 1;
    }
    for(myPanel m : mp)
    {
        m.tock();
    }
    for(short x = 0; x < 3; x++ )
    {
        mp[x].tock();
        jl[x].setText( "" + --tim[x]  );
    }
}


private class myPanel extends JPanel
{
//Fields
    private boolean finished = false;
    //(x,y) Coords
    private short x = 15;
    private short y = 50;
    //Size and shape
    private short width = 200;
    private short height = 10;
    private short arcSize = 10;
    //Bar essentials
    private double max; //highest range of bar
    private double fill = width; //sets filled in portion
    private double tick; //calculates movement per event
    private Color urgent = Color.BLUE; // Changes the color depending on the   Urgency

//Constructors
    public myPanel()
    {
        this.setBackground( Color.WHITE );
        repaint();
    }

//Mutators ( tick manipulation )
    public void setMax( double maxIn )
    {
        this.max = maxIn;
        System.out.println("Max: " + this.max );
        this.tick = (double)width / this.max;
        System.out.println("tick: " + this.tick );
    }

//Methods
    //Tick Manipulation
    public void tock()
    {   
        //Ends when zero
        if( fill < 1 )
        {
            fill = width;
            finished = true;
            tick = 0;
            urgent = Color.BLUE;
            repaint();
        }
        else
        {   
            fill -= tick ;
            System.out.println("fill is " + fill );
            repaint();
        }

    }
    //Paint method
    public void paint( Graphics g)
    {
        super.paint(g);
        Graphics2D g2 = (Graphics2D)g;
        g2.setColor( urgent );
        g2.draw(new RoundRectangle2D.Double(x,y + 40, width, height, arcSize, arcSize) );
        g2.fill(new RoundRectangle2D.Double(x,y + 40, fill , height, arcSize, arcSize) );
    }
 }
public static void main(String[] args)
  {
    plaything pt = new plaything();
    pt.setVisible(true);
  }
}

My real only concern is where is my logic flawed concerning the progression of the bars and the labels. I hope to find how to make both reach zero together. (two days of research and work on just the bars alone)

Again thank you for your time.

Answer 1

You’re calling tock() twice every iteration of your Timer:

    for(myPanel m : mp)
    {
        m.tock(); // ONCE
    }
    for(short x = 0; x < 3; x++ )
    {
        mp[x].tock(); // TWICE
        jl[x].setText( "" + --tim[x]  );
    }

You should remove one call, or the other.