ch7_e7_28.java

来自「各种关于JAVA的初级编程」· Java 代码 · 共 58 行

import java.awt.*; 
import java.awt.event.*;

public class ch7_e7_28 
{
    public static void main(String args[])
    {
        new MyFrame();
    }
}

class MyFrame extends Frame implements AdjustmentListener
{
    Scrollbar mySlider = new Scrollbar(
        Scrollbar.HORIZONTAL,0,1,0,400);
    int radius = 0;
    int x=200,y=200;
    
    MyFrame()
    {
        super("我的窗口");
        
        mySlider.setUnitIncrement(1);
        mySlider.setBlockIncrement(10);
        
        setLayout(new BorderLayout());
        add("North",mySlider);
        mySlider.addAdjustmentListener(this);
        
        addWindowListener(new closeWin());
        setSize(650,400);
        setVisible(true);
    }
    public void paint(Graphics g)
    {
        g.drawOval(x-radius,y-radius,radius*2,radius*2);
    }
    public void adjustmentValueChanged(AdjustmentEvent ae)
    {
        if(ae.getAdjustable() == mySlider)
        {
            radius = ae.getValue()/2;
            repaint();
        }
    }
    
}

class closeWin extends WindowAdapter
{
    public void windowClosing(WindowEvent we)
    {
        Frame frm = (Frame)we.getWindow();
        frm.dispose();
        System.exit(0);
    }
}