Buttons and Method

[imagiro1]

This is my first GUI attempt. It's for a servo control program I am working on. When I call the method servo.move(10), it will move the servo to 10 degrees. I have this working on a text based program, but I am getting an error when I try with the GUI. The error is commented next to the line servoA.move(10). Not sure why it doesn't work. Thanks.

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

public class guiTest
{  
   private static final int FRAME_WIDTH = 800;
   private static final int FRAME_HEIGHT = 600;

   public static void main(String[] args) throws Exception
   {  
      JFrame frame = new JFrame();
      
      // Create new servo
      final servoBackbone servoA = new servoBackbone();
      
      // The button to trigger the calculation
      JButton increase = new JButton("Increase Angle");
      JButton decrease = new JButton("Decrease Angle");

      // The panel that holds the user interface components
      JPanel panel = new JPanel();
      panel.add(increase);
      panel.add(decrease);      
      frame.add(panel);
      
      class AddInterestListener implements ActionListener
      {
         public void actionPerformed(ActionEvent event)
         {
           servoA.move(10); //unreported exception java.lang.Exception; must be caught or declared to be thrown.
         }            
      }
      
      ActionListener listener = new AddInterestListener();
      increase.addActionListener(listener);
      decrease.addActionListener(listener);

      frame.setSize(FRAME_WIDTH, FRAME_HEIGHT);
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.setVisible(true);
   }
}

[camickr]

The move(...) method throws an exception so you must catch it.

If you have this working in your text based program then see what you did there and do the same thing here.

I'm sure your text book has a section on "exception handling".

[imagiro1]

Gotcha. Thanks. I was just reading the book and saw an example using try and catch. I changed it to this and it works. Still not sure how these exceptions work. I took a programming class at school never got to learning GUI's or exceptions. So I'm trying to learn.

try {
     servoA.move(10);
      }
catch (Exception e){
      System.err.println(e.toString());
}