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Dial.javaAPI DocExample4013Mon May 01 14:41:54 BST 2000None

Dial

public class Dial extends JComponent

Fields Summary
int
minValue
int
value
int
maxValue
int
radius
Constructors Summary
public Dial()

 this(0, 100, 0);
public Dial(int minValue, int maxValue, int value)

    this.minValue = minValue;
    this.maxValue = maxValue;
    this.value = value;
    setForeground(Color.lightGray);

    addMouseListener(new MouseAdapter(  ) {
      public void mousePressed(MouseEvent e) { spin(e); }
    });
    addMouseMotionListener(new MouseMotionAdapter(  ) {
      public void mouseDragged(MouseEvent e) { spin(e); }
    });
Methods Summary
public voidaddDialListener(DialListener listener)

    listenerList.add( DialListener.class, listener );
private voiddraw3DCircle(java.awt.Graphics g, int x, int y, int radius, boolean raised)

    Color foreground = getForeground(  );
    Color light = foreground.brighter(  );
    Color dark = foreground.darker(  );
    g.setColor(foreground);
    g.fillOval(x, y, radius * 2, radius * 2);
    g.setColor(raised ? light : dark);
    g.drawArc(x, y, radius * 2, radius * 2, 45, 180);
    g.setColor(raised ? dark : light);
    g.drawArc(x, y, radius * 2, radius * 2, 225, 180);
voidfireEvent()

    Object[] listeners = listenerList.getListenerList(  );
    for ( int i = 0; i < listeners.length; i += 2 )
      if ( listeners[i] == DialListener.class )
        ((DialListener)listeners[i + 1]).dialAdjusted(
          new DialEvent(this, value) );
public intgetMaximum()

 return maxValue;
public intgetMinimum()

 return minValue;
public java.awt.DimensiongetPreferredSize()

    return new Dimension(100, 100);
public intgetValue()

 return value;
public static voidmain(java.lang.String[] args)

    JFrame f = new JFrame("Dial v1.0");
    f.addWindowListener( new WindowAdapter(  ) {
      public void windowClosing(WindowEvent e) { System.exit(0); }
    });
    f.setSize(150, 150);

    final JLabel statusLabel = new JLabel("Welcome to Dial v1.0");
    final Dial dial = new Dial(  );
    JPanel dialPanel = new JPanel(  );
    dialPanel.add(dial);
    f.getContentPane(  ).add(dialPanel, BorderLayout.CENTER);
    f.getContentPane(  ).add(statusLabel, BorderLayout.SOUTH);

    dial.addDialListener(new DialListener(  ) {
      public void dialAdjusted(DialEvent e) {
        statusLabel.setText("Value is " + e.getValue(  ));
      }
    });
    f.setVisible( true );
public voidpaintComponent(java.awt.Graphics g)

    Graphics2D g2 = (Graphics2D)g;
    int tick = 10;
    radius = getSize(  ).width / 2 - tick;
    g2.setPaint(getForeground().darker(  ));
    g2.drawLine(radius * 2 + tick / 2, radius,
        radius * 2 + tick, radius);
    g2.setStroke(new BasicStroke(2));
    draw3DCircle(g2, 0, 0, radius, true);
    int knobRadius = radius / 7;
    double th = value * (2 * Math.PI) / (maxValue - minValue);
    int x = (int)(Math.cos(th) * (radius - knobRadius * 3)),
    y = (int)(Math.sin(th) * (radius - knobRadius * 3));
    g2.setStroke(new BasicStroke(1));
    draw3DCircle(g2, x + radius - knobRadius,
                 y + radius - knobRadius, knobRadius, false );
public voidremoveDialListener(DialListener listener)

    listenerList.remove( DialListener.class, listener );
public voidsetMaximum(int maxValue)

 this.maxValue = maxValue;
public voidsetMinimum(int minValue)

 this.minValue = minValue;
public voidsetValue(int value)

    firePropertyChange( "value", this.value, value );
    this.value = value;
    repaint(  );
    fireEvent(  );
protected voidspin(java.awt.event.MouseEvent e)

    int y = e.getY(  );
    int x = e.getX(  );
    double th = Math.atan((1.0 * y - radius) / (x - radius));
    int value=((int)(th / (2 * Math.PI) * (maxValue - minValue)));
    if (x < radius)
      setValue(value + maxValue / 2);
    else if (y < radius)
      setValue(value + maxValue);
    else
      setValue(value);