ch16l03.txt

《Web编程专家指南》

Listing 16.3 PopDial class.

import java.awt.*;

class PopDial extends Dial
    {
        public PopDial(String aName, int aLowVal, int aHighVal,
                       int aTicksEvery, long aSweepTime, Color fColor){
            super(aName, aLowVal, aHighVal, aTicksEvery, aSweepTime, fColor);
        }

        public void paint(Graphics g){
            Rectangle myExtent = this.bounds();
            g.drawOval(0, 0, myExtent.width, myExtent.height);
            if(flash == true){
                long curTime = java.lang.System.currentTimeMillis();
                long millisSince = curTime - 836327000000L;
                long population = millisSince / sweepTime + 265232323;
                String myLabel = "U.S. Pop: " + population;
                g.setColor(flashColor);
                g.fillOval(0, 0, myExtent.width, myExtent.height);
                g.setColor(Color.black);
                g.drawString(myLabel, 0, myExtent.height / 2);
                System.out.println(myLabel);
                flash = false;
            }else{
                //convert percent done into an arc...
                int arcDegrees = (int) (percent * 360);
                g.fillArc(0, 0, myExtent.width, myExtent.height, 90,
                          arcDegrees);
            }
        }
    }