我做了一个简单的例子,还没有完善好,只是起到一个抛砖引玉的作用,希望你能自己把它补完整.
package test;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.border.LineBorder;
public class DrawFn extends JFrame{
private JTextField txt_interval;
private JTextField txt_c;
private JTextField txt_b;
private JTextField txt_a;
private drawFnPanel panel = new drawFnPanel();
/**
* @param args
*/
public static void main(String[] args) {
DrawFn frame=new DrawFn();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
public DrawFn() {
super();
getContentPane().setLayout(null);
final JLabel aLabel = new JLabel();
aLabel.setText("a=");
aLabel.setBounds(10,10,21,18);
getContentPane().add(aLabel);
txt_a = new JTextField();
txt_a.setBounds(31,8,87,22);
getContentPane().add(txt_a);
final JLabel bLabel = new JLabel();
bLabel.setText("b=");
bLabel.setBounds(136,10,21,18);
getContentPane().add(bLabel);
txt_b = new JTextField();
txt_b.setBounds(159,8,87,22);
getContentPane().add(txt_b);
final JLabel cLabel = new JLabel();
cLabel.setText("c=");
cLabel.setBounds(267,10,32,18);
getContentPane().add(cLabel);
txt_c = new JTextField();
txt_c.setBounds(290,8,87,22);
getContentPane().add(txt_c);
final JLabel label = new JLabel();
label.setText("步长=");
label.setBounds(398,10,47,18);
getContentPane().add(label);
txt_interval = new JTextField();
txt_interval.setBounds(440,8,87,22);
getContentPane().add(txt_interval);
final JButton button = new JButton();
button.addActionListener(new draw_actionAdapter(this));
button.setText("绘制");
button.setBounds(533,5,61,28);
getContentPane().add(button);
panel.setBorder(new LineBorder(Color.black,1,false));
panel.setBounds(10,36,599,389);
getContentPane().add(panel);
}
public void paintFn(ActionEvent e){
panel.paintFn(Integer.parseInt(txt_a.getText()),Integer.parseInt(txt_b.getText()),Integer.parseInt(txt_c.getText()),Integer.parseInt(txt_interval.getText()));
}
}
class drawFnPanel extends JPanel{
private int _a=0;
private int _b=0;
private int _c=0;
private float _interval=0.01f;
public void paintFn(int a,int b,int c,int interval){
_a=a;
_b=b;
_c=c;
_interval=interval;
repaint();
}
private double getY(float x){
return _a*x*x+_b*x+_c;
}
public void paintComponent(Graphics g){
Graphics2D g2d=(Graphics2D)g;
if(_a==0 && _b==0 && _c==0){
return;
}
for(float i=-100f;i
