题目要求:
在一个JComboBox选中其中的Rect,在面板内画个矩形,选中Circle 则画个圆.
以下是小弟写的程序:
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
public class DrawCombo {
public static void main(String[] args)
{
Drawframe frame=new Drawframe();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.show();
}
}
class Drawframe extends JFrame
{
Drawpanel s;
private JComboBox drawCombo;
public Drawframe()
{
setTitle("DrawFrame");
setSize(300,200);
drawCombo=new JComboBox();
drawCombo.setEditable(false);
drawCombo.addItem("Circle");
drawCombo.addItem("Rect");
drawCombo.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent event)
{
String s2=(String)drawCombo.getSelectedItem();
if(s2=="Circle"){ s.drawf(Drawpanel.CIRCLE);}
else if (s2=="Rect"){s.drawf(Drawpanel.SQUARE);}
}
});
Drawpanel panel=new Drawpanel();
Container contentPane=getContentPane();
JPanel comboPanel=new JPanel();
comboPanel.add(drawCombo);
contentPane.add(panel);
contentPane.add(comboPanel,BorderLayout.SOUTH);
}
}
class Drawpanel extends JPanel
{
public final static int CIRCLE = 1,SQUARE = 2;
private int shape;
public void paintComponent(Graphics g)
{
super.paintComponent(g);
Graphics2D f2=(Graphics2D)g;
Rectangle2D rect=new Rectangle.Double(100,100,200,150);
double x=rect.getCenterX();
double y=rect.getCenterY();
double r=50;
Ellipse2D circle=new Ellipse2D.Double();
circle.setFrameFromCenter(x,y,x+r,y+r);
if ( shape == CIRCLE)
{f2.draw(circle);}
else if (shape == SQUARE )
{f2.draw(rect);}
}
public void drawf (int shapeToDraw)
{
shape = shapeToDraw;
repaint();
}
}
不知道那里错了.请哪位大侠帮帮忙.
急
