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Thread: Need help building a simple calculator

  1. #1
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    Default Need help building a simple calculator

    I am trying to get the number keys right now to post there number in the tf text field.
    Right now I am getting a few errors and noting happens when you click one the buttons.

    here my code

    import java.awt.BorderLayout;
    import java.awt.GridLayout;
    import java.awt.event.ActionEvent;
    import java.awt.event.ActionListener;
    import java.awt.event.ItemEvent;
    import java.awt.event.ItemListener;
     
    import javax.swing.JButton;
    import javax.swing.JFrame;
    import javax.swing.JLabel;
    import javax.swing.JPanel;
    import javax.swing.JRadioButton;
    import javax.swing.JTextField;
     
     
     
     
    public class BasicGUI extends JFrame implements ActionListener {
     
    	private JButton b0, b1, b2, b3, b4, b5, b6, b7, b8, b9, plus, equal;
    	private JTextField tf;
    	private JPanel display, keypad;
    	private GridLayout bGrid;
     
    	private class MyListener implements ActionListener {
    		public void actionPerformed(ActionEvent e){
    			JButton b = (JButton)e.getSource();
     
    			String output = "";
     
    			if (b == b0){
    				output += "0";
    			} else if (b == b1){
    				output += "1";
    			} else if (b == b2){
    				output += "2";
    			} else if (b == b3){
    				output += "3";
    			} else if (b == b4){
    				output += "4";
    			}else if (b == b5){
    				output += "5";
    			}else if (b == b6){
    				output += "6";
    			}else if (b == b7){
    				output += "7";
    			}else if (b == b8){
    				output += "8";
    			}else if (b == b9){
    				output += "9";
    			}
     
    			//tarea.setText(out);
    			tf.setText(output);
     
     
    		}
    	}
     
     
    	public BasicGUI() {
     
    		super("My First GUI Application");
     
    		this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
     
     
    		bGrid = new GridLayout(4, 3, 2, 2);
     
    		keypad = new JPanel(bGrid);
    		display = new JPanel();
     
    		b0 = new JButton("0");
    		b1 = new JButton("1");
    		b2 = new JButton("2");
    		b3 = new JButton("3");
    		b4 = new JButton("4");
    		b5 = new JButton("5");
    		b6 = new JButton("6");
    		b7 = new JButton("7");
    		b8 = new JButton("8");
    		b9 = new JButton("9");
    		plus = new JButton("+");
    		equal = new JButton("=");
     
    		keypad.add(b0);
    		keypad.add(b1);
    		keypad.add(b2);
    		keypad.add(b3);
    		keypad.add(b4);
    		keypad.add(b5);
    		keypad.add(b6);
    		keypad.add(b7);
    		keypad.add(b8);
    		keypad.add(b9);
    		keypad.add(plus);
    		keypad.add(equal);
     
     
    		tf = new JTextField(20);
    		display.add(tf);
     
     
     
     
    		this.add(display, BorderLayout.NORTH);
    		this.add(keypad, BorderLayout.SOUTH);
     
     
    		this.pack();
     
     
    	}
    	/**
    	 * @param args
    	 */
    	public static void main(String[] args) {
     
    		new BasicGUI().setVisible(true);
     
    	}
    	@Override
    	public void actionPerformed(ActionEvent arg0) {
    		// TODO Auto-generated method stub
     
    	}
     
    }

    Thank you for any help you can give.


  2. #2
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    Default Re: Need help building a simple calculator

    What are your errors? Are the compiler errors or runtime errors? Post them here.
    Useful links: How to Ask Questions the Smart Way | Use Code Tags | Java Tutorials
    Static Void Games - Play indie games, learn from game tutorials and source code, upload your own games!

  3. #3
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    Default Re: Need help building a simple calculator

    errors are fixed, but I am having problems register my buttons to post to the tf text field when you click on them.

  4. #4
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    Default Re: Need help building a simple calculator

    lol, ok I see what i was doing wrong. sometimes a good night rest and a new look can solve many problems.

    here is my new working code,
    feel free to try it and use it

    import java.awt.BorderLayout;
    import java.awt.GridLayout;
    import java.awt.event.ActionEvent;
    import java.awt.event.ActionListener;
    import java.awt.event.ItemEvent;
    import java.awt.event.ItemListener;
     
    import javax.swing.JButton;
    import javax.swing.JFrame;
    import javax.swing.JLabel;
    import javax.swing.JPanel;
    import javax.swing.JRadioButton;
    import javax.swing.JTextField;
     
     
     
     
    public class BasicGUI extends JFrame implements ActionListener {
     
    	private JButton b0, b1, b2, b3, b4, b5, b6, b7, b8, b9, plus, equal;
    	private JTextField tf;
    	private JPanel display, keypad;
    	private GridLayout bGrid;
    	String strIn = "";
    	String strOut = "";
    	String str = "";
    	int output = 0;
     
     
    	public BasicGUI() {
     
    		super("My First GUI Application");
     
    		this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
     
     
    		bGrid = new GridLayout(4, 3, 2, 2);
     
    		keypad = new JPanel(bGrid);
    		display = new JPanel();
     
    		b0 = new JButton("0");
    		b1 = new JButton("1");
    		b2 = new JButton("2");
    		b3 = new JButton("3");
    		b4 = new JButton("4");
    		b5 = new JButton("5");
    		b6 = new JButton("6");
    		b7 = new JButton("7");
    		b8 = new JButton("8");
    		b9 = new JButton("9");
    		plus = new JButton("+");
    		equal = new JButton("=");
     
     
    		b0.addActionListener(new ActionListener() {  
                public void actionPerformed(ActionEvent e)
                {
                    System.out.println("You clicked the 0 button");
                    strIn = strIn+"0";
                    tf.setText(strIn);
     
                }});
    		b1.addActionListener(new ActionListener() {  
                public void actionPerformed(ActionEvent e)
                {
                    System.out.println("You clicked the 1 button");
                    strIn = strIn+"1";
                    tf.setText(strIn);
     
                }});
    		b2.addActionListener(new ActionListener() {  
                public void actionPerformed(ActionEvent e)
                {
                    System.out.println("You clicked the 2 button");
                    strIn = strIn+"2";
                    tf.setText(strIn);
     
                }});
    		b3.addActionListener(new ActionListener() {  
                public void actionPerformed(ActionEvent e)
                {
                    System.out.println("You clicked the 3 button");
                    strIn = strIn+"3";
                    tf.setText(strIn);
     
                }});
    		b4.addActionListener(new ActionListener() {  
                public void actionPerformed(ActionEvent e)
                {
                    System.out.println("You clicked the 4 button");
                    strIn = strIn+"4";
                    tf.setText(strIn);
     
                }});
    		b5.addActionListener(new ActionListener() {  
                public void actionPerformed(ActionEvent e)
                {
                    System.out.println("You clicked the 5 button");
                    strIn = strIn+"5";
                    tf.setText(strIn);
     
                }});
    		b6.addActionListener(new ActionListener() {  
                public void actionPerformed(ActionEvent e)
                {
                    System.out.println("You clicked the 6 button");
                    strIn = strIn+"6";
                    tf.setText(strIn);
     
                }});
    		b7.addActionListener(new ActionListener() {  
                public void actionPerformed(ActionEvent e)
                {
                    System.out.println("You clicked the 7 button");
                    strIn = strIn+"7";
                    tf.setText(strIn);
     
                }});
    		b8.addActionListener(new ActionListener() {  
                public void actionPerformed(ActionEvent e)
                {
                    System.out.println("You clicked the 8 button");
                    strIn = strIn+"8";
                    tf.setText(strIn);
     
                }});
    		b9.addActionListener(new ActionListener() {  
                public void actionPerformed(ActionEvent e)
                {
                    System.out.println("You clicked the 9 button");
                    strIn = strIn+"9";
                    tf.setText(strIn);
     
                }});
    		plus.addActionListener(new ActionListener() {  
                public void actionPerformed(ActionEvent e)
                {
                    System.out.println("You clicked the plus button");
                    output = Integer.parseInt( strIn )+output;
                    str = strIn +  "+" + str;	
                    strOut = str;
                    strIn = "";
                    tf.setText(strOut);
     
     
                }});
    		equal.addActionListener(new ActionListener() {  
                public void actionPerformed(ActionEvent e)
                {
                    System.out.println("You clicked the equal button");
                    output = Integer.parseInt( strIn )+output;
                    str = str + strIn;	
                    strOut = str;
                    strOut = strOut +  "=" + Integer.toString(output);	
                    tf.setText(strOut);
                    strIn = "";
                    strOut = "";
                    str = "";
                    output = 0;
     
                }});
     
    		keypad.add(b0);
    		keypad.add(b1);
    		keypad.add(b2);
    		keypad.add(b3);
    		keypad.add(b4);
    		keypad.add(b5);
    		keypad.add(b6);
    		keypad.add(b7);
    		keypad.add(b8);
    		keypad.add(b9);
    		keypad.add(plus);
    		keypad.add(equal);
     
     
    		tf = new JTextField(20);
    		display.add(tf);
     
     
     
    		this.add(display, BorderLayout.NORTH);
    		this.add(keypad, BorderLayout.SOUTH);
     
     
    		this.pack();
     
     
    	}
    	/**
    	 * @param args
    	 */
    	public static void main(String[] args) {
     
    		new BasicGUI().setVisible(true);
     
    	}
    	@Override
    	public void actionPerformed(ActionEvent arg0) {
    		// TODO Auto-generated method stub
     
    	}
     
    }
    Last edited by zigma; October 13th, 2011 at 10:22 PM.

  5. #5
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    Default Re: Need help building a simple calculator

    I just improved my code, new code posted below

    import java.awt.BorderLayout;
    import java.awt.GridLayout;
    import java.awt.event.ActionEvent;
    import java.awt.event.ActionListener;
    import java.awt.event.ItemEvent;
    import java.awt.event.ItemListener;
     
    import javax.swing.JButton;
    import javax.swing.JFrame;
    import javax.swing.JLabel;
    import javax.swing.JPanel;
    import javax.swing.JRadioButton;
    import javax.swing.JTextField;
     
    public class BasicGUI extends JFrame implements ActionListener {
     
    	private JButton b0, b1, b2, b3, b4, b5, b6, b7, b8, b9, plus, equal;
    	private JTextField tf;
    	private JPanel display, keypad;
    	private GridLayout bGrid;
    	String outputTf = "";
    	int output = 0;
    	String n = "";
    	String i = "";
    	int num = 0;
     
     
    	public void actionPerformed(ActionEvent e) { // event handler
    		JButton b = (JButton) e.getSource();
     
    		if (b == b0) {
    			i = Integer.toString(0);
    			n = n +  Integer.toString(0);
     
    		} else if (b == b1) {
    			i = Integer.toString(1);
    			n = n +  Integer.toString(1);
     
    		} else if (b == b2) {
    			i = Integer.toString(2);
    			n = n +  Integer.toString(2);
     
    		} else if (b == b3) {
    			i = Integer.toString(3);
    			n = n +  Integer.toString(3);
     
    		} else if (b == b4) {
    			i = Integer.toString(4);
    			n = n +  Integer.toString(4);
     
    		} else if (b == b5) {
    			i = Integer.toString(5);
    			n = n +  Integer.toString(5);
     
    		} else if (b == b6) {
    			i = Integer.toString(6);
    			n = n +  Integer.toString(6);
     
    		} else if (b == b7) {
    			i = Integer.toString(7);
    			n = n +  Integer.toString(7);
     
    		} else if (b == b8) {
    			i = Integer.toString(8);
    			n = n +  Integer.toString(8);
     
    		} else if (b == b9) {
    			i = Integer.toString(9);
    			n = n +  Integer.toString(9);
     
    		} else if (b == plus) {
    			num = num + Integer.parseInt(n);
    			n="";
    			i = "+";
     
     
    		} else if (b == equal) {
    			output = num + Integer.parseInt(n);
    			i = "="+ output;
    		}
     
    		outputTf = outputTf + i;
    		tf.setText(outputTf);
    	}
     
    	public BasicGUI() {
     
    		super("My First GUI Application");
     
    		this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
     
    		bGrid = new GridLayout(4, 3, 2, 2);
     
    		keypad = new JPanel(bGrid);
    		display = new JPanel();
     
    		b0 = new JButton("0");
    		b1 = new JButton("1");
    		b2 = new JButton("2");
    		b3 = new JButton("3");
    		b4 = new JButton("4");
    		b5 = new JButton("5");
    		b6 = new JButton("6");
    		b7 = new JButton("7");
    		b8 = new JButton("8");
    		b9 = new JButton("9");
    		plus = new JButton("+");
    		equal = new JButton("=");
     
    		keypad.add(b0);
    		keypad.add(b1);
    		keypad.add(b2);
    		keypad.add(b3);
    		keypad.add(b4);
    		keypad.add(b5);
    		keypad.add(b6);
    		keypad.add(b7);
    		keypad.add(b8);
    		keypad.add(b9);
    		keypad.add(plus);
    		keypad.add(equal);
     
    		tf = new JTextField(20);
    		display.add(tf);
     
    		this.add(display, BorderLayout.NORTH);
    		this.add(keypad, BorderLayout.SOUTH);
    		this.pack();
     
    		// register the event listener with the buttons
     
    		b0.addActionListener(this);
    		b1.addActionListener(this);
    		b2.addActionListener(this);
    		b3.addActionListener(this);
    		b4.addActionListener(this);
    		b5.addActionListener(this);
    		b6.addActionListener(this);
    		b7.addActionListener(this);
    		b8.addActionListener(this);
    		b9.addActionListener(this);
    		plus.addActionListener(this);
    		equal.addActionListener(this);
    	}
     
    	/**
    	 * @param args
    	 */
    	public static void main(String[] args) {
     
    		new BasicGUI().setVisible(true);
    	}
    }

  6. The Following User Says Thank You to zigma For This Useful Post:

    ikocijan (June 20th, 2012)

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