compiled but not running

[jide agboola]

I have just written this code for calculating the perimeter and area of Rectangle, i was able to compile it but still couldn't run it, could anyone please help me have a look at it.

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
 

public class periArea extends JFrame {
 //declaring component b4 contructor method
 
    JFrame frame;
    JLabel lbLenght,lbWidth;
    JTextField lenghtField,widthField, resultField;
    JButton areaBtn, perimeterBtn;
 
 //Button handlers
 
    private areaBtnHandler aBH;
    private perimeterBtnHandler pBH; 
 
    JPanel row1, row2, row3;
 
 public periArea() {
 
    frame.setTitle("Area and Perimeter");
    frame.setSize(400,400);
    frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
    frame.setVisible(true);
 
//initializing components inside constructor method
 
  lbLenght = new JLabel("LENGHT", JLabel.RIGHT);
  lbWidth =  new JLabel("WIDTH",JLabel.RIGHT);
 
  lenghtField = new JTextField(10);
  widthField  = new JTextField(10);
  resultField = new JTextField(10);
 
  areaBtn      = new JButton("AREA");
  perimeterBtn = new JButton("PERIMETER");
 
 //adding actin Listener to buttons 
 
 areaBtn.addActionListener(aBH);
 perimeterBtn.addActionListener(pBH); 
  
 

 
// declaring and initialising pane
 
  Container pane = getContentPane();
 
//adding components to frame via panels
 

  row1.add(lbLenght);
  row1.add(lenghtField);
  row1.add(lbWidth);
  row1.add(widthField);
  pane.add(row1);
 
  row2.add(resultField);
  pane.add(row2);
 
  row3.add(areaBtn);
  row3.add(perimeterBtn);
  pane.add(row3);
  
 
     }
    private class areaBtnHandler implements ActionListener {
 
    public void actionPerformed(ActionEvent e)
   {  double x,  y,  z;
 

    x = Double.parseDouble(lenghtField.getText());
    y = Double.parseDouble(widthField.getText());
    z = x * y;
    
    resultField.setText("AREA:"  + z);
   }
}
 
private class perimeterBtnHandler implements ActionListener 
  {
   public void actionPerformed(ActionEvent e)
  { double p, q, r;
  
    p = Double.parseDouble(lenghtField.getText());
    q = Double.parseDouble(widthField.getText());
    r = (2*p) + (2 * q);
 
   resultField.setText("PERIMETER:"  + r);
 
  }
}
 

   public static void main(String[] args) {
   
   periArea pA = new periArea();
    
  }
}
   

[Gregg Bolinger]

What happens when you run it? What should it do that it is not doing? Are there runtime errors? A stacktrace perhaps?

[Michael Dunn]

these go together
public class periArea extends JFrame {
Container pane = getContentPane();
pane.add(row1);
pane.add(row2);
pane.add(row3);


and these go together
JFrame frame;
frame.setTitle("Area and Perimeter");
frame.setSize(400,400);
frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
frame.setVisible(true);

the two are not the same JFrame - you should be able to work out the fix.

when fixed, your next question will be "only row3 shows" - JFrame's default
LayoutManager is BorderLayout - read the apidocs for BorderLayout to see how
multiple components should be added.