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Thread: methods help

  1. #1
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    Default methods help

    I need to write a program that prompts the user to enter 4 integers (x1, x2, y1, y2) and the program should output the circles area, diameter, circumference, and area. I have to create these methods, distance, radius, circumference and area.

    I have the code done but everytime i enter the integers, it doesnt work. Can anybody help me with this?

    import javax.swing.*;
    import java.awt.*;
    import java.awt.event.*;
     
     
     
    public class Circle extends JFrame {
     
       // declare variables
       private double radius = 0, circ = 0, diameter = 0, area = 0, distance = 0; 
       private double X1, X2, Y1, Y2;
       private ButtonHandler buttonHandler;
     
     
       // declare GUI components
       JLabel lX1, lX2, lY1, lY2, lWelcome, lRadius, lCirc, lDiameter, lArea;
       JTextField tX1, tX2, tY1, tY2, tRadius, tCirc, tDiameter, tArea;
       JButton bReset, bCompute;
       Container c;
       JPanel pCenter;
     
       //set and get methods
       public double distance (double X1, double X2, double Y1, double Y2)
       {
       	distance =  Math.sqrt((X2 - X1) * (X2 - X1) + (Y2 - Y1) * (Y2 - Y1));
       	return distance;
       }
     
       public double radius (double X1, double Y1, double X2, double Y2)
       {
    	return distance(X1, Y1, X2, Y2);
       }
     
       public double circ (double radius)
       {
    	circ = 2*Math.PI * radius;
    	return circ;
       }
     
       public double area (double radius)
       {
    	area = Math.PI * radius * radius; 
    	return area;
       }   
       {
     
     
     
     
             //create GUI components
             lX1 = new JLabel("Enter X1:");
             lX2 = new JLabel("Enter X2:");
             lY1 = new JLabel("Enter Y1:");
             lY2 = new JLabel("Enter Y2:");
             lRadius = new JLabel("Radius =");
             lCirc = new JLabel("Circumference =");
             lDiameter = new JLabel("Diameter =");
             lArea = new JLabel("Area =");
             lWelcome = new JLabel("Circle", SwingConstants.CENTER);
     
             tX1 = new JTextField("");
             tX2 = new JTextField("");
             tY1 = new JTextField("");
             tY2 = new JTextField("");
             tRadius = new JTextField("");
             tCirc = new JTextField("");
             tDiameter = new JTextField("");
             tArea = new JTextField("");
     
             tX1.setEditable(true);
             tX2.setEditable(true);
             tY1.setEditable(true);
             tY2.setEditable(true);
             tRadius.setEditable(false);
             tCirc.setEditable(false);
             tDiameter.setEditable(false);
             tArea.setEditable(false);
     
             bReset = new JButton("Reset");
             bCompute = new JButton("Compute");
     
             c = getContentPane();
             pCenter = new JPanel();
       }
     
             public Circle() {
             //add GUI components
             pCenter.setLayout(new GridLayout(9,2));
             pCenter.add(lX1);
             pCenter.add(tX1);
             pCenter.add(lX2);
             pCenter.add(tX2);
             pCenter.add(lY1);
             pCenter.add(tY1);
             pCenter.add(lY2);
             pCenter.add(tY2);
             pCenter.add(lRadius);
             pCenter.add(tRadius);
             pCenter.add(lCirc);
             pCenter.add(tCirc);
             pCenter.add(lDiameter);
             pCenter.add(tDiameter);
             pCenter.add(lArea);
             pCenter.add(tArea);
             pCenter.add(bReset);
             pCenter.add(bCompute);
     
             c.setLayout(new BorderLayout());
             c.add(lWelcome, BorderLayout.NORTH);
             c.add(pCenter, BorderLayout.CENTER);
     
             //register with buttons
             buttonHandler = new ButtonHandler();
             bReset.addActionListener(buttonHandler);
             bCompute.addActionListener(buttonHandler);
     
             //render the window
             setTitle("Circle Info");
             setSize(500, 300);
             setLocation(100, 100);
             setResizable(false);
             setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
             setVisible(true);
       }
     
       private class ButtonHandler implements ActionListener {
          public void actionPerformed(ActionEvent ae) {
             if (ae.getSource().equals(bReset)) {
                tX1.setText("");
                tX2.setText("");
                tY1.setText("");
                tY2.setText("");
                tRadius.setText("");
                tCirc.setText("");
                tDiameter.setText("");
                tArea.setText("");
             }
             else {
                 try {
                   X1 = Double.parseDouble(tX1.getText());
                   X2 = Double.parseDouble(tX2.getText());
                   Y1 = Double.parseDouble(tY1.getText());
                   Y2 = Double.parseDouble(tY2.getText());
                   radius = Double.parseDouble(tRadius.getText());
                   circ = Double.parseDouble(tCirc.getText());
                   diameter = Double.parseDouble(tDiameter.getText());
                   area = Double.parseDouble(tArea.getText());
                 }
     
     
                  catch (Exception e) {
                       JOptionPane.showMessageDialog(null, "Invalid input, please try again");
                       return;
                     }
             }
          }
       }          
     
     public static void main(String[] args) {
           Circle myApp = new Circle();
       } 
     }


  2. #2
    Super Moderator helloworld922's Avatar
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    Default Re: methods help

    Your action listener is trying to read in the radius, diameter, circumference, and area of the circle rather than computing the values and setting the text. Use the setText() method to set the text once you have computed to desired quantities.

    Also, if you're suppose to enter integers, it would be better to use the Integer.parseInt() method rather than the Double.parseDouble() method.

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