Re: pls hlep, can't get output

On 10/17/2011 9:00 PM, kk wrote:


This seems to work. To use a Timer, you have to set up the Timer with a
1000 second delay, start it, and then ask the component be redrawn by
calling its repaint() method. That's all I did, besides removing the
loop. Read carefully and make sure you understand.

Oh, and your AWT Canvas is thread safe, but the JFrame is not. Please
read up on multithreading in Swing.

package quicktest;

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
import java.util.Calendar;

class ClockDemo extends Canvas
{

    Timer timer = new Timer( 1000, new TimerTick() );

    int xmou = 200; //set the center of circle
    int ymou = 200; //set the center of circle
    double theta = -0.1047; //theta for second's hand
    int x = xmou; //x position of Second's hand
    int y = ymou; //y position of second's hand
    int p, b;
    int h;
    boolean flag = true;
    /*ClockDemo(){
    //super();
    setSize(500,500);
    setBackground(Color.PINK);
    setVisible(true);
    }*/

    public ClockDemo()
    {
       timer.start();
    }

    @Override
    public void paint( Graphics g )
    {
       DrawLine( g, xmou, ymou, x, y );
    }

    public void DrawLine( Graphics g, int startX, int startY, int endX,
int endY )
    {
       h = 80;
       System.out.println( "h:" + h );
       //g.drawLine(200,200,165,248);
       g.drawLine( startX, startY, endX, endY );
       newpoint();
       //this.repaint(startX,startY,endX,endY);
    }

    public void newpoint()
    {
       //creating a Calendarvariable for getting current time
       Calendar now = Calendar.getInstance();

       //for second hand
       //h=60;
       x = xmou;
       y = ymou;
       theta = -0.1047;
       theta = theta * now.get( Calendar.SECOND );
       System.out.println( "theta:" + theta );
       p = (int) ( Math.sin( theta ) * h );
       b = (int) ( Math.cos( theta ) * h );
       System.out.println( "p:" + p + " " + "b:" + b );
       x = x - p;
       y = y - b;

    }

    private class TimerTick implements ActionListener {
       public void actionPerformed( ActionEvent e ) {
          repaint();
       }
    }
}

public class CanvasTest
{
    public static void main( String... arg )
    {
       final ClockDemo comp = new ClockDemo();
       SwingUtilities.invokeLater( new Runnable() {
          public void run() {
             JFrame jf = new JFrame( "Clock Demo" );
             jf.add( comp );
             jf.setSize( 500, 500 );
             jf.setVisible( true );
             jf.setDefaultCloseOperation( WindowConstants.EXIT_ON_CLOSE );
          }
       } );
    }
}