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Thread: Another Calculator Problem

  1. December 4th, 2010, 03:31 PM #1
    The_Mexican
    The_Mexican is offline
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    Join Date
    Feb 2010
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    Thanked 1 Time in 1 Post

    Default Another Calculator Problem

    EDIT: Nevermind, solved it.


    Hi guys, another problem with my calculator program has arose. I have added a button which will make the input positive or negative depending on what it is (I have also added many other things). To make something positive from negative, I delete the first character (assuming it should be a -). The problem is, sometimes it deletes the first character when it is suppose to put a negative in front of the input. It seems random when it does this. For example, if you click the buttons in this order: 3, +/-, +, 6, +/- the 6 will be deleted instead of getting a - sign in front of it.

    Here is a runnable code:
    package JFrameClaculator;
 
import java.awt.Color;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
 
import javax.swing.AbstractButton;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextField;
import javax.swing.SpringLayout;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
 
import layout.testing2;
 
public class Calculator extends JPanel implements ActionListener{
 
	public static void main(String[] args) {
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
            }
        });
    }
	static String textop;
	static String textop1;
	static int x;
	static int x1;
	static int x2;
	static int x3;
	static int y = 1;
	public static final char LF = '\n';
	public static final char CR = '\r';
	static JTextField textField;
	protected static JButton b1;
	protected static JButton b2;
	protected static JButton b3;
	protected static JButton b4;
	protected static JButton b5;
	protected static JButton b6;
	protected static JButton b7;
	protected static JButton b8;
	protected static JButton b9;
	protected static JButton b10;
	protected static JButton b11;
	protected static JButton b12;
	protected static JButton b13;
	protected static JButton b14;
	protected static JButton b15;
	protected static JButton b16;
	protected static JButton b17;
	protected static JButton b18;
	private static void createAndShowGUI() {
		JFrame frame = new JFrame("Calculator v2.1");
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		Container contentPane = frame.getContentPane();
        SpringLayout layout = new SpringLayout();
        contentPane.setLayout(layout);
        String lookAndFeel = "com.sun.java.swing.plaf.windows.WindowsLookAndFeel";
        try {
			UIManager.setLookAndFeel(lookAndFeel);
		} catch (ClassNotFoundException e) {
			String ErrorMessage = "Error: "+e; 
			JScrollPane scrollPane = new JScrollPane(new JLabel(ErrorMessage));  
			scrollPane.setPreferredSize(new Dimension(100, 50));  
			Object message = scrollPane;  
			JOptionPane.showMessageDialog(null, message, "Error", JOptionPane.ERROR_MESSAGE);      
			try {
				UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
			} catch (ClassNotFoundException e1) {
				String ErrorMessage1 = "Error: "+e1; 
				JScrollPane scrollPane1 = new JScrollPane(new JLabel(ErrorMessage1));  
				scrollPane1.setPreferredSize(new Dimension(100, 50));  
				Object message1 = scrollPane1;  
				JOptionPane.showMessageDialog(null, message1, "Error", JOptionPane.ERROR_MESSAGE);      
				System.exit(0);
			} catch (InstantiationException e1) {
				String ErrorMessage1 = "Error: "+e1; 
				JScrollPane scrollPane1 = new JScrollPane(new JLabel(ErrorMessage1));  
				scrollPane1.setPreferredSize(new Dimension(100, 50));  
				Object message1 = scrollPane1;  
				JOptionPane.showMessageDialog(null, message1, "Error", JOptionPane.ERROR_MESSAGE);      
				System.exit(0);
			} catch (IllegalAccessException e1) {
				String ErrorMessage1 = "Error: "+e1; 
				JScrollPane scrollPane1 = new JScrollPane(new JLabel(ErrorMessage1));  
				scrollPane1.setPreferredSize(new Dimension(100, 50));  
				Object message1 = scrollPane1;  
				JOptionPane.showMessageDialog(null, message1, "Error", JOptionPane.ERROR_MESSAGE);      
				System.exit(0);
			} catch (UnsupportedLookAndFeelException e1) {
				String ErrorMessage1 = "Error: "+e1; 
				JScrollPane scrollPane1 = new JScrollPane(new JLabel(ErrorMessage1));  
				scrollPane1.setPreferredSize(new Dimension(100, 50));  
				Object message1 = scrollPane1;  
				JOptionPane.showMessageDialog(null, message1, "Error", JOptionPane.ERROR_MESSAGE);      
				System.exit(0);
			}
		} catch (InstantiationException e) {
			String ErrorMessage = "Error: "+e; 
			JScrollPane scrollPane = new JScrollPane(new JLabel(ErrorMessage));  
			scrollPane.setPreferredSize(new Dimension(100, 50));  
			Object message = scrollPane;  
			JOptionPane.showMessageDialog(null, message, "Error", JOptionPane.ERROR_MESSAGE);      
			try {
				UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
			} catch (ClassNotFoundException e1) {
				String ErrorMessage1 = "Error: "+e1; 
				JScrollPane scrollPane1 = new JScrollPane(new JLabel(ErrorMessage1));  
				scrollPane1.setPreferredSize(new Dimension(100, 50));  
				Object message1 = scrollPane1;  
				JOptionPane.showMessageDialog(null, message1, "Error", JOptionPane.ERROR_MESSAGE);      
				System.exit(0);
			} catch (InstantiationException e1) {
				String ErrorMessage1 = "Error: "+e1; 
				JScrollPane scrollPane1 = new JScrollPane(new JLabel(ErrorMessage1));  
				scrollPane1.setPreferredSize(new Dimension(100, 50));  
				Object message1 = scrollPane1;  
				JOptionPane.showMessageDialog(null, message1, "Error", JOptionPane.ERROR_MESSAGE);      
				System.exit(0);
			} catch (IllegalAccessException e1) {
				String ErrorMessage1 = "Error: "+e1; 
				JScrollPane scrollPane1 = new JScrollPane(new JLabel(ErrorMessage1));  
				scrollPane1.setPreferredSize(new Dimension(100, 50));  
				Object message1 = scrollPane1;  
				JOptionPane.showMessageDialog(null, message1, "Error", JOptionPane.ERROR_MESSAGE);      
				System.exit(0);
			} catch (UnsupportedLookAndFeelException e1) {
				String ErrorMessage1 = "Error: "+e1; 
				JScrollPane scrollPane1 = new JScrollPane(new JLabel(ErrorMessage1));  
				scrollPane1.setPreferredSize(new Dimension(100, 50));  
				Object message1 = scrollPane1;  
				JOptionPane.showMessageDialog(null, message1, "Error", JOptionPane.ERROR_MESSAGE);      
				System.exit(0);
			}
		} catch (IllegalAccessException e) {
			String ErrorMessage = "Error: "+e; 
			JScrollPane scrollPane = new JScrollPane(new JLabel(ErrorMessage));  
			scrollPane.setPreferredSize(new Dimension(100, 50));  
			Object message = scrollPane;  
			JOptionPane.showMessageDialog(null, message, "Error", JOptionPane.ERROR_MESSAGE);      
			try {
				UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
			} catch (ClassNotFoundException e1) {
				String ErrorMessage1 = "Error: "+e1; 
				JScrollPane scrollPane1 = new JScrollPane(new JLabel(ErrorMessage1));  
				scrollPane1.setPreferredSize(new Dimension(100, 50));  
				Object message1 = scrollPane1;  
				JOptionPane.showMessageDialog(null, message1, "Error", JOptionPane.ERROR_MESSAGE);      
				System.exit(0);
			} catch (InstantiationException e1) {
				String ErrorMessage1 = "Error: "+e1; 
				JScrollPane scrollPane1 = new JScrollPane(new JLabel(ErrorMessage1));  
				scrollPane1.setPreferredSize(new Dimension(100, 50));  
				Object message1 = scrollPane1;  
				JOptionPane.showMessageDialog(null, message1, "Error", JOptionPane.ERROR_MESSAGE);      
				System.exit(0);
			} catch (IllegalAccessException e1) {
				String ErrorMessage1 = "Error: "+e1; 
				JScrollPane scrollPane1 = new JScrollPane(new JLabel(ErrorMessage1));  
				scrollPane1.setPreferredSize(new Dimension(100, 50));  
				Object message1 = scrollPane1;  
				JOptionPane.showMessageDialog(null, message1, "Error", JOptionPane.ERROR_MESSAGE);      
				System.exit(0);
			} catch (UnsupportedLookAndFeelException e1) {
				String ErrorMessage1 = "Error: "+e1; 
				JScrollPane scrollPane1 = new JScrollPane(new JLabel(ErrorMessage1));  
				scrollPane1.setPreferredSize(new Dimension(100, 50));  
				Object message1 = scrollPane1;  
				JOptionPane.showMessageDialog(null, message1, "Error", JOptionPane.ERROR_MESSAGE);      
				System.exit(0);
			}
		} catch (UnsupportedLookAndFeelException e) {
			String ErrorMessage = "Error: "+e; 
			JScrollPane scrollPane = new JScrollPane(new JLabel(ErrorMessage));  
			scrollPane.setPreferredSize(new Dimension(100, 50));  
			Object message = scrollPane;  
			JOptionPane.showMessageDialog(null, message, "Error", JOptionPane.ERROR_MESSAGE);      
			try {
				UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
			} catch (ClassNotFoundException e1) {
				String ErrorMessage1 = "Error: "+e1; 
				JScrollPane scrollPane1 = new JScrollPane(new JLabel(ErrorMessage1));  
				scrollPane1.setPreferredSize(new Dimension(100, 50));  
				Object message1 = scrollPane1;  
				JOptionPane.showMessageDialog(null, message1, "Error", JOptionPane.ERROR_MESSAGE);      
				System.exit(0);
			} catch (InstantiationException e1) {
				String ErrorMessage1 = "Error: "+e1; 
				JScrollPane scrollPane1 = new JScrollPane(new JLabel(ErrorMessage1));  
				scrollPane1.setPreferredSize(new Dimension(100, 50));  
				Object message1 = scrollPane1;  
				JOptionPane.showMessageDialog(null, message1, "Error", JOptionPane.ERROR_MESSAGE);      
				System.exit(0);
			} catch (IllegalAccessException e1) {
				String ErrorMessage1 = "Error: "+e1; 
				JScrollPane scrollPane1 = new JScrollPane(new JLabel(ErrorMessage1));  
				scrollPane1.setPreferredSize(new Dimension(100, 50));  
				Object message1 = scrollPane1;  
				JOptionPane.showMessageDialog(null, message1, "Error", JOptionPane.ERROR_MESSAGE);      
				System.exit(0);
			} catch (UnsupportedLookAndFeelException e1) {
				String ErrorMessage1 = "Error: "+e1; 
				JScrollPane scrollPane1 = new JScrollPane(new JLabel(ErrorMessage1));  
				scrollPane1.setPreferredSize(new Dimension(100, 50));  
				Object message1 = scrollPane1;  
				JOptionPane.showMessageDialog(null, message1, "Error", JOptionPane.ERROR_MESSAGE);      
				System.exit(0);
			}
		}
        textField = new JTextField("", 23);
        textField.setEditable(false);
        textField.setBackground(Color.white);
        Font f = new Font("+/-", Font.PLAIN, 11);
        b1 = new JButton("1");
        b1.setVerticalTextPosition(AbstractButton.CENTER);
        b1.setHorizontalTextPosition(AbstractButton.LEADING);
        b1.addActionListener(new Calculator());
        b1.setActionCommand("1");
        b1.setForeground(Color.blue);
        b2 = new JButton("2");
        b2.setVerticalTextPosition(AbstractButton.CENTER);
        b2.setHorizontalTextPosition(AbstractButton.LEADING);
        b2.addActionListener(new Calculator());
        b2.setActionCommand("2");
        b2.setForeground(Color.blue);
        b3 = new JButton("3");
        b3.setVerticalTextPosition(AbstractButton.CENTER);
        b3.setHorizontalTextPosition(AbstractButton.LEADING);
        b3.addActionListener(new Calculator());
        b3.setActionCommand("3");
        b3.setForeground(Color.blue);
        b4 = new JButton("4");
        b4.setVerticalTextPosition(AbstractButton.CENTER);
        b4.setHorizontalTextPosition(AbstractButton.LEADING);
        b4.addActionListener(new Calculator());
        b4.setActionCommand("4");
        b4.setForeground(Color.blue);
        b5 = new JButton("5");
        b5.setVerticalTextPosition(AbstractButton.CENTER);
        b5.setHorizontalTextPosition(AbstractButton.LEADING);
        b5.addActionListener(new Calculator());
        b5.setActionCommand("5");
        b5.setForeground(Color.blue);
        b6 = new JButton("6");
        b6.setVerticalTextPosition(AbstractButton.CENTER);
        b6.setHorizontalTextPosition(AbstractButton.LEADING);
        b6.addActionListener(new Calculator());
        b6.setActionCommand("6");
        b6.setForeground(Color.blue);
        b7 = new JButton("7");
        b7.setVerticalTextPosition(AbstractButton.CENTER);
        b7.setHorizontalTextPosition(AbstractButton.LEADING);
        b7.addActionListener(new Calculator());
        b7.setActionCommand("7");
        b7.setForeground(Color.blue);
        b8 = new JButton("8");
        b8.setVerticalTextPosition(AbstractButton.CENTER);
        b8.setHorizontalTextPosition(AbstractButton.LEADING);
        b8.addActionListener(new Calculator());
        b8.setActionCommand("8");
        b8.setForeground(Color.blue);
        b9 = new JButton("9");
        b9.setVerticalTextPosition(AbstractButton.CENTER);
        b9.setHorizontalTextPosition(AbstractButton.LEADING);
        b9.addActionListener(new Calculator());
        b9.setActionCommand("9");
        b9.setForeground(Color.blue);
        b10 = new JButton("0");
        b10.setVerticalTextPosition(AbstractButton.CENTER);
        b10.setHorizontalTextPosition(AbstractButton.LEADING);
        b10.addActionListener(new Calculator());
        b10.setActionCommand("0");
        b10.setForeground(Color.blue);
        b11 = new JButton("+");
        b11.setVerticalTextPosition(AbstractButton.CENTER);
        b11.setHorizontalTextPosition(AbstractButton.LEADING);
        b11.addActionListener(new Calculator());
        b11.setActionCommand("+");
        b11.setForeground(Color.red);
        b12 = new JButton("-");
        b12.setVerticalTextPosition(AbstractButton.CENTER);
        b12.setHorizontalTextPosition(AbstractButton.LEADING);
        b12.addActionListener(new Calculator());
        b12.setActionCommand("-");
        b12.setForeground(Color.red);
        b13 = new JButton("x");
        b13.setVerticalTextPosition(AbstractButton.CENTER);
        b13.setHorizontalTextPosition(AbstractButton.LEADING);
        b13.addActionListener(new Calculator());
        b13.setActionCommand("x");
        b13.setForeground(Color.red);
        b14 = new JButton("/");
        b14.setVerticalTextPosition(AbstractButton.CENTER);
        b14.setHorizontalTextPosition(AbstractButton.LEADING);
        b14.addActionListener(new Calculator());
        b14.setActionCommand("/");
        b14.setForeground(Color.red);
        b15 = new JButton("C");
        b15.setVerticalTextPosition(AbstractButton.CENTER);
        b15.setHorizontalTextPosition(AbstractButton.LEADING);
        b15.addActionListener(new Calculator());
        b15.setActionCommand("C");
        b15.setForeground(Color.red);
        b16 = new JButton("=");
        b16.setVerticalTextPosition(AbstractButton.CENTER);
        b16.setHorizontalTextPosition(AbstractButton.LEADING);
        b16.addActionListener(new Calculator());
        b16.setActionCommand("=");
        b16.setForeground(Color.red);
        b17 = new JButton(".");
        b17.setVerticalTextPosition(AbstractButton.CENTER);
        b17.setHorizontalTextPosition(AbstractButton.LEADING);
        b17.addActionListener(new Calculator());
        b17.setActionCommand(".");
        b17.setForeground(Color.blue);
        b18 = new JButton("+/-");
        b18.setVerticalTextPosition(AbstractButton.CENTER);
        b18.setHorizontalTextPosition(AbstractButton.LEADING);
        b18.addActionListener(new Calculator());
        b18.setActionCommand("+/-");
        b18.setFont(f);
        b18.setForeground(Color.blue);
        contentPane.setBackground(new Color(240, 240, 240));
        contentPane.add(textField);
        contentPane.add(b1);
        contentPane.add(b2);
        contentPane.add(b3);
        contentPane.add(b4);
        contentPane.add(b5);
        contentPane.add(b6);
        contentPane.add(b7);
        contentPane.add(b8);
        contentPane.add(b9);
        contentPane.add(b10);
        contentPane.add(b11);
        contentPane.add(b12);
        contentPane.add(b13);
        contentPane.add(b14);
        contentPane.add(b15);
        contentPane.add(b16);
        contentPane.add(b17);
        contentPane.add(b18);
        b1.setPreferredSize(new Dimension(45, 30));
        b2.setPreferredSize(new Dimension(45, 30));
        b3.setPreferredSize(new Dimension(45, 30));
        b4.setPreferredSize(new Dimension(45, 30));
        b5.setPreferredSize(new Dimension(45, 30));
        b6.setPreferredSize(new Dimension(45, 30));
        b7.setPreferredSize(new Dimension(45, 30));
        b8.setPreferredSize(new Dimension(45, 30));
        b9.setPreferredSize(new Dimension(45, 30));
        b10.setPreferredSize(new Dimension(45, 30));
        b11.setPreferredSize(new Dimension(45, 30));
        b12.setPreferredSize(new Dimension(45, 30));
        b13.setPreferredSize(new Dimension(45, 30));
        b14.setPreferredSize(new Dimension(45, 30));
        b15.setPreferredSize(new Dimension(45, 30));
        b16.setPreferredSize(new Dimension(145, 30));
        b17.setPreferredSize(new Dimension(45, 30));
        b18.setPreferredSize(new Dimension(45, 30));
        //SET HEIGHT/WIDTH
        layout.putConstraint(SpringLayout.WEST, textField,
                             30,
                             SpringLayout.WEST, contentPane);
        layout.putConstraint(SpringLayout.NORTH, textField,
                             10,
                             SpringLayout.NORTH, contentPane);
        //END SET HEIGHT/WIDTH
      //SET HEIGHT/WIDTH
        layout.putConstraint(SpringLayout.WEST, b1,
                             30,
                             SpringLayout.WEST, contentPane);
        layout.putConstraint(SpringLayout.NORTH, b1,
                             110,
                             SpringLayout.NORTH, contentPane);
        //END SET HEIGHT/WIDTH
        //SET HEIGHT/WIDTH
        layout.putConstraint(SpringLayout.WEST, b2,
                             80,
                             SpringLayout.WEST, contentPane);
        layout.putConstraint(SpringLayout.NORTH, b2,
                             110,
                             SpringLayout.NORTH, contentPane);
        //END SET HEIGHT/WIDTH
      //SET HEIGHT/WIDTH
        layout.putConstraint(SpringLayout.WEST, b3,
                             130,
                             SpringLayout.WEST, contentPane);
        layout.putConstraint(SpringLayout.NORTH, b3,
                             110,
                             SpringLayout.NORTH, contentPane);
        //END SET HEIGHT/WIDTH
      //SET HEIGHT/WIDTH
        layout.putConstraint(SpringLayout.WEST, b4,
                             30,
                             SpringLayout.WEST, contentPane);
        layout.putConstraint(SpringLayout.NORTH, b4,
                             75,
                             SpringLayout.NORTH, contentPane);
        //END SET HEIGHT/WIDTH
      //SET HEIGHT/WIDTH
        layout.putConstraint(SpringLayout.WEST, b5,
                             80,
                             SpringLayout.WEST, contentPane);
        layout.putConstraint(SpringLayout.NORTH, b5,
                             75,
                             SpringLayout.NORTH, contentPane);
        //END SET HEIGHT/WIDTH
      //SET HEIGHT/WIDTH
        layout.putConstraint(SpringLayout.WEST, b6,
                             130,
                             SpringLayout.WEST, contentPane);
        layout.putConstraint(SpringLayout.NORTH, b6,
                             75,
                             SpringLayout.NORTH, contentPane);
        //END SET HEIGHT/WIDTH
      //SET HEIGHT/WIDTH
        layout.putConstraint(SpringLayout.WEST, b7,
                             30,
                             SpringLayout.WEST, contentPane);
        layout.putConstraint(SpringLayout.NORTH, b7,
                             40,
                             SpringLayout.NORTH, contentPane);
        //END SET HEIGHT/WIDTH
      //SET HEIGHT/WIDTH
        layout.putConstraint(SpringLayout.WEST, b8,
                             80,
                             SpringLayout.WEST, contentPane);
        layout.putConstraint(SpringLayout.NORTH, b8,
                             40,
                             SpringLayout.NORTH, contentPane);
        //END SET HEIGHT/WIDTH
      //SET HEIGHT/WIDTH
        layout.putConstraint(SpringLayout.WEST, b9,
                             130,
                             SpringLayout.WEST, contentPane);
        layout.putConstraint(SpringLayout.NORTH, b9,
                             40,
                             SpringLayout.NORTH, contentPane);
        //END SET HEIGHT/WIDTH
      //SET HEIGHT/WIDTH
        layout.putConstraint(SpringLayout.WEST, b10,
                             30,
                             SpringLayout.WEST, contentPane);
        layout.putConstraint(SpringLayout.NORTH, b10,
                             145,
                             SpringLayout.NORTH, contentPane);
        //END SET HEIGHT/WIDTH
      //SET HEIGHT/WIDTH
        layout.putConstraint(SpringLayout.WEST, b11,
                             180,
                             SpringLayout.WEST, contentPane);
        layout.putConstraint(SpringLayout.NORTH, b11,
                             40,
                             SpringLayout.NORTH, contentPane);
        //END SET HEIGHT/WIDTH
      //SET HEIGHT/WIDTH
        layout.putConstraint(SpringLayout.WEST, b12,
                             180,
                             SpringLayout.WEST, contentPane);
        layout.putConstraint(SpringLayout.NORTH, b12,
                             75,
                             SpringLayout.NORTH, contentPane);
        //END SET HEIGHT/WIDTH
      //SET HEIGHT/WIDTH
        layout.putConstraint(SpringLayout.WEST, b13,
                             180,
                             SpringLayout.WEST, contentPane);
        layout.putConstraint(SpringLayout.NORTH, b13,
                             110,
                             SpringLayout.NORTH, contentPane);
        //END SET HEIGHT/WIDTH
      //SET HEIGHT/WIDTH
        layout.putConstraint(SpringLayout.WEST, b14,
                             180,
                             SpringLayout.WEST, contentPane);
        layout.putConstraint(SpringLayout.NORTH, b14,
                             145,
                             SpringLayout.NORTH, contentPane);
        //END SET HEIGHT/WIDTH
      //SET HEIGHT/WIDTH
        layout.putConstraint(SpringLayout.WEST, b15,
                             130,
                             SpringLayout.WEST, contentPane);
        layout.putConstraint(SpringLayout.NORTH, b15,
                             145,
                             SpringLayout.NORTH, contentPane);
        //END SET HEIGHT/WIDTH
      //SET HEIGHT/WIDTH
        layout.putConstraint(SpringLayout.WEST, b16,
                             30,
                             SpringLayout.WEST, contentPane);
        layout.putConstraint(SpringLayout.NORTH, b16,
                             180,
                             SpringLayout.NORTH, contentPane);
        //END SET HEIGHT/WIDTH
      //SET HEIGHT/WIDTH
        layout.putConstraint(SpringLayout.WEST, b17,
                             80,
                             SpringLayout.WEST, contentPane);
        layout.putConstraint(SpringLayout.NORTH, b17,
                             145,
                             SpringLayout.NORTH, contentPane);
        //END SET HEIGHT/WIDTH
      //SET HEIGHT/WIDTH
        layout.putConstraint(SpringLayout.WEST, b18,
                             180,
                             SpringLayout.WEST, contentPane);
        layout.putConstraint(SpringLayout.NORTH, b18,
                             180,
                             SpringLayout.NORTH, contentPane);
        //END SET HEIGHT/WIDTH
        frame.pack();
        frame.setSize(263, 259);
        frame.setLocation(20, 20);
        frame.setVisible(true);
        frame.setResizable(false);
	}
	public void actionPerformed(ActionEvent e) {
		if (e.getSource()==b1) {
			String text = textField.getText();
			textField.setText(text+"1");
		}
		if (e.getSource()==b2) {
			String text = textField.getText();
			textField.setText(text+"2");
		}
		if (e.getSource()==b3) {
			String text = textField.getText();
			textField.setText(text+"3");
		}
		if (e.getSource()==b4) {
			String text = textField.getText();
			textField.setText(text+"4");
		}
		if (e.getSource()==b5) {
			String text = textField.getText();
			textField.setText(text+"5");
		}
		if (e.getSource()==b6) {
			String text = textField.getText();
			textField.setText(text+"6");
		}
		if (e.getSource()==b7) {
			String text = textField.getText();
			textField.setText(text+"7");
		}
		if (e.getSource()==b8) {
			String text = textField.getText();
			textField.setText(text+"8");
		}
		if (e.getSource()==b9) {
			String text = textField.getText();
			textField.setText(text+"9");
		}
		if (e.getSource()==b10) {
			String text = textField.getText();
			textField.setText(text+"0");
		}
		if (e.getSource()==b11) {
			textop = textField.getText();
			textField.setText("");
			x = x + 1;
		}
		if (e.getSource()==b12) {
			textop = textField.getText();
			textField.setText("");
			x1 = x1 + 1;
		}
		if (e.getSource()==b13) {
			textop = textField.getText();
			textField.setText("");
			x2 = x2 + 1;
		}
		if (e.getSource()==b14) {
			textop = textField.getText();
			textField.setText("");
			x3 = x3 + 1;
		}
		if (e.getSource()==b15) {
			String str = textField.getText();
			if (str == null) {
 
		      }
		      int strLen = str.length();
		      if(strLen != 0){
		      if (strLen < 2) {
		          textField.setText("");
		      }
		      int lastIdx = strLen - 1;
		      String ret = str.substring(0, lastIdx);
		      char last = str.charAt(lastIdx);
		      if (last == LF) {
		          if (ret.charAt(lastIdx - 1) == CR) {
		              textField.setText(ret.substring(0, lastIdx - 1));
		          }
		      }
		      textField.setText(ret);
			}
		}
		if (e.getSource()==b16) {
			try{
			if(x % 2 != 0)
			{
				textop1 = textField.getText();
				float op = Float.valueOf(textop).floatValue();
				float op1 = Float.valueOf(textop1).floatValue();
				float opFinal = op+op1;
				String Final = Float.toString(opFinal);
				textField.setText(Final);
				x = x + 1;
			}
			if(x1 % 2 != 0)
			{
				textop1 = textField.getText();
				float op = Float.valueOf(textop).floatValue();
				float op1 = Float.valueOf(textop1).floatValue();
				float opFinal = op-op1;
				String Final = Float.toString(opFinal);
				textField.setText(Final);
				x1 = x1 + 1;
			}
			if(x2 % 2 != 0)
			{
				textop1 = textField.getText();
				float op = Float.valueOf(textop).floatValue();
				float op1 = Float.valueOf(textop1).floatValue();
				float opFinal = op*op1;
				String Final = Float.toString(opFinal);
				textField.setText(Final);
				x2 = x2 + 1;
			}
			if(x3 % 2 != 0)
			{
				textop1 = textField.getText();
				float op = Float.valueOf(textop).floatValue();
				float op1 = Float.valueOf(textop1).floatValue();
				float opFinal = op/op1;
				String Final = Float.toString(opFinal);
				textField.setText(Final);
				x3 = x3 + 1;
			}
			else
			{
 
			}
			}catch(Exception e1){
				String ErrorMessage = "Error: "+e1; 
				JScrollPane scrollPane = new JScrollPane(new JLabel(ErrorMessage));  
				scrollPane.setPreferredSize(new Dimension(100, 50));  
				Object message = scrollPane;  
				JOptionPane.showMessageDialog(null, message, "Error", JOptionPane.ERROR_MESSAGE);      
				textField.setText("");
				x = 0;
				x1 = 0;
				x2 = 0;
				x3 = 0;
				y = 1;
			}
		}
		if (e.getSource()==b17) {
			String text = textField.getText();
			textField.setText(text+".");
		}
		if (e.getSource()==b18) {
			try{
			if(y % 2 != 0)
			{
				String text = textField.getText();
				textField.setText("-"+text);
				y = y + 1;
			}
			else if(y % 2 == 0)
			{
				String text = textField.getText();
				int pos = text.length()-text.length(); 
		        String newValue  = text.substring(0,pos) + text.substring(pos+1);
		        textField.setText(newValue);
		        y = y + 1;
			}
			}catch(Exception e2)
			{
				String ErrorMessage = "Error: "+e2; 
				JScrollPane scrollPane = new JScrollPane(new JLabel(ErrorMessage));  
				scrollPane.setPreferredSize(new Dimension(100, 50));  
				Object message = scrollPane;  
				JOptionPane.showMessageDialog(null, message, "Error", JOptionPane.ERROR_MESSAGE);      
				textField.setText("");
				x = 0;
				x1 = 0;
				x2 = 0;
				x3 = 0;
				y = 1;
			}
		}
	}
 
}

    Here is what I think the relevant code is:
    //y starts out as 1
if (e.getSource()==b18) {
			try{
			if(y % 2 != 0)
			{
				String text = textField.getText();
				textField.setText("-"+text);
				y = y + 1;
			}
			else if(y % 2 == 0)
			{
				String text = textField.getText();
				int pos = text.length()-text.length(); 
		        String newValue  = text.substring(0,pos) + text.substring(pos+1);
		        textField.setText(newValue);
		        y = y + 1;
			}
			}catch(Exception e2)
			{
				String ErrorMessage = "Error: "+e2; 
				JScrollPane scrollPane = new JScrollPane(new JLabel(ErrorMessage));  
				scrollPane.setPreferredSize(new Dimension(100, 50));  
				Object message = scrollPane;  
				JOptionPane.showMessageDialog(null, message, "Error", JOptionPane.ERROR_MESSAGE);      
				textField.setText("");
				x = 0;
				x1 = 0;
				x2 = 0;
				x3 = 0;
				y = 1;
			}
    Last edited by The_Mexican; December 4th, 2010 at 06:14 PM.
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