Applet exceptions

Comments

• demaja

  May 2011

  Sorry. Somehow, I pasted it twice--once within itself.
  
  import javax.swing.JOptionPane;
  import java.awt.Graphics;
  import java.awt.Color;
  import javax.swing.JApplet;
  
  
  public class BallGrows extends JApplet
  {
  public void paint(Graphics g)
  {
  super.paint(g);
  
  final int X = 250;
  final int Y = 250;
  final Color COLOR = Color.BLUE;
  
  String rad1 = JOptionPane.showInputDialog(null, "Beginning radius:");
  String rad2 = JOptionPane.showInputDialog(null, "Ending radius:");
  
  int r1 = Integer.parseInt(rad1);
  int r2 = Integer.parseInt(rad2);
  
  for(int i = r1; i <= r2; i++)
  {
  g.setColor(COLOR);
  
  g.fillOval(X - i, Y - i, i*2, i*2);
  }
  
  }
  }
  
• demaja

  May 2011

  I fixed the exceptions by adding a Pause class using the wait() method, but the dialog boxes and console still ask the user for input twice. How do I fix that?
  
  class Pause
  {
  static void wait(double seconds){}
  }
  
• silveredge52

  May 2011

  Hey,
  This code eliminates the double prompts.
  [code]
  import java.awt.Color;
  import java.awt.Graphics;
  import java.awt.event.ActionEvent;
  import java.awt.event.ActionListener;
  import javax.swing.JApplet;
  import javax.swing.JButton;
  import javax.swing.JOptionPane;
  
  public class BallGrows extends JApplet {
  
  String rad1, rad2;
  
  public void start() {
  getInput();
  }
  
  public void getInput() {
  rad1 = JOptionPane.showInputDialog(null, "Beginning radius:");
  rad2 = JOptionPane.showInputDialog(null, "Ending radius:");
  }
  
  public void paint(Graphics g) {
  super.paint(g);
  final int X = 250;
  final int Y = 250;
  final Color COLOR = Color.BLUE;
  
  
  int r1 = 25; // default values
  int r2 = 25; // default values
  if (rad1 != null) {
  r1 = Integer.parseInt(rad1);
  }
  if (rad2 != null) {
  r2 = Integer.parseInt(rad2);
  }
  
  g.setColor(COLOR);
  for (int i = r1; i <= r2; i++) {
  g.fillOval(X - i, Y - i, i * 2, i * 2);
  g.drawOval(X - i, Y - i, i * 2, i * 2); // missing statement
  }
  }
  }[/code]
  The java virtual machine will invoke the paint() routine whenever it thinks it needs to be done. Thus the frequent input prompts.
  
  
  regards, se52
• demaja

  May 2011

  Thanks for the reply!!! I'm sorry, but your code is waaaaaaaaay beyond the point that I'm at in my book. What I am working on at the moment is making a class that receives the input and then another class that paints it.
  
• demaja

  May 2011

  Btw, I'm not sure why you said that "g.drawOval(X - i, Y - i, i * 2, i * 2);" was a missing statement. g.fillOval draws a filled oval, which is what I want. I don't need to draw it then fill it, b/c it's all done in one go. But, perhaps there is something more to it that I'm missing? Thanks!