CIS 260 - Calculator I

CIS 260 Assignment: Calculator I

The objective for this assignment is to be able to construct working GUI components following specifications. These components will be used to construct your next project. I have test program listings at the bottom of this page which can do some superficial testing of your components to see if they are working. Please note that the tests are not thorough and your code may still have problems even if it manages to pass the tests. You are expected to test and debug your own code.

Keypad Project (Keypad.java)

You have two major tasks for this assignment. The first is to create the following keypad GUI:

Here are the requirements for the keypad:

it must extend a container (JPanel)
you will need 23 buttons total (see picture for text inside buttons and layout of buttons)
the constructor should:
1. set the proper layout
2. create the containers (JPanels) you will need
3. create the appropriate buttons and add them to the containers (JPanels)
4. set the proper colors for the text inside the buttons
5. add the containers (JPanels) to the keypad
6. Note: It would be easiest if the number buttons are referenced by an array so you don't have to deal with 23 names
there should be an addActionListener routine
1. JPanels don't normally have them (but your's will)
2. accept an ActionListener as an argument
3. add the listener to each button on the keypad (this is easier if all the buttons are just elements of an array)

When you are done with your keypad, you can test it with the driver listed below. It should display the text from the buttons you click in the console window.

/*
   TestKeypad.java
   CIS 260 Calculator 1 Assignmnet
*/

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

public class TestKeypad extends JFrame implements ActionListener {
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                new TestKeypad();
            }
        });
    }

    public TestKeypad() {
        init();
    }

    public void init() {
        try {
            UIManager.setLookAndFeel(
               "com.sun.java.swing.plaf.windows.WindowsLookAndFeel");
        } catch (Exception e) {
            e.printStackTrace(System.err);
        }
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        Keypad k = new Keypad();
        Container c = getContentPane();
        c.setLayout(new BorderLayout());
        c.add(k);
        k.addActionListener(this);
        setSize(220,200);
        setVisible(true);
    }

    public void actionPerformed(ActionEvent e) {
        final ActionEvent event = e;
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                JButton b = (JButton) event.getSource();
                System.out.println(b.getActionCommand());
            }
        });
    }
}

Number Field Project (NumField.java)

The second part of this project is to create a text field which will display numbers. Think of it as a display for a calculator. The tricky part is to only allow valid numbers.

Here are the requirements for the number field:

base your class on a JTextField
you should have a boolean variable to tell you whether the field currently contains a decimal point
the constructor should:
- set the background color to white
- make the field non-editable by the user
- clear the field
- make sure the decimal point indicator is false
you should have the following methods:
- public double getValue()
  Return the current value of the number field as a double.
- public void setValue(double)
  This method should set the number field to the double value passed to it. It should do this by converting the double to a String and calling setText(String) [see below]
- public void clear()
  Clear the number field and reset the decimal point indicator.
- public void append(char)
  Check to see if the character passed in is legal. If it is, then append it to the number field. Don't forget to set the decimal indicator if needed.
- public void append(String)
  Append each character of the String individually.
- public void setText(String)
  Clear the number field and then append the String.
- public void setError(String)
  Set the text of the text field to whatever String was pased in.
- private boolean isLegal(char)
  This method determines whether it would be valid to append the char passed in. Here are the rules:
  - if the char is a digit, then it's legal
  - otherwise, if the char is a period, then it is legal if the decimal point indicator is false, and illegal if the decimal point indicator is true
  - otherwise, if the char is a '-' and the field is currently blank or "0", then it is legal
  - otherwise, the char is illegal

When you are done with your number field, you can test it with the driver listed below. It should display testing information in the console window.

/*
   TestNumField.java
   CIS 260 Calculator 1 assignment
*/

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

public class TestNumField extends JFrame {
    NumField nf;

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                new TestNumField();
            }
        });
    }

    public TestNumField() {
        init();
    }

    public void init() {
        try {
            UIManager.setLookAndFeel(
               "com.sun.java.swing.plaf.windows.WindowsLookAndFeel");
        } catch (Exception e) {
            e.printStackTrace(System.err);
        }
        Container c = getContentPane();
        c.setLayout(new BorderLayout());
        nf = new NumField();
        c.add(nf);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setSize(200,60);
        setVisible(true);
        start();
    }

    public void start() {
        System.out.println("Testing Number Field...");

        nf.setValue(123.89);
        if (nf.getText().equals("123.89"))
            System.out.println("...passed setting value test");
        else
            System.out.println("...failed setting value test");

        double d = nf.getValue();
        if (d == 123.89)
            System.out.println("...passed getting value test");
        else
            System.out.println("...failed getting value test");

        nf.append('1');
        System.out.println(nf.getText());
        System.out.println("The line above should read: 123.891");

        nf.append(".7");
        System.out.println(nf.getText());
        System.out.println("The line above should read: 123.8917");

        nf.clear();
        System.out.println(nf.getText());
        System.out.println("The line above should be blank");

        nf.append("124.43");
        System.out.println(nf.getText());
        System.out.println("The line above should read: 124.43");
        System.out.println("Your GUI should also read: 124.43");
    }
}

Your test output should look like this:

Testing Number Field...
...passed setting value test
...passed getting value test
123.891
The line above should read: 123.891
123.8917
The line above should read: 123.8917

The line above should be blank
124.43
The line above should read: 124.43
Your GUI should also read: 124.43