Question

QUESTION 3 [49 MARKS 3.1) Write the Java statements for a class called Calculator to produce the GUI below. Use 3 panels to arrange the components. You must use an array when defining the numbered buttons (o-9. Do not declare 10 buttons individually. The textfield must be initialized with the text as shown below, and be able to accommodate up to 25 characters. The spacing between the numbered buttons is 10. (28) for caloula Add Equals 3.2 Rewrite any existing Java code of the class definition in 3.1 which needs to be changed, as well as any additional event-handling code, to display the appropriate numeric value in the textfield when the user cicks on the numbered buttons. If the user clicks on a combination of numbers then the entire multi-digit number is displayed in the textfield 3.3 Now write further Java statements to do the following Once the user has clicked a digit or combination of digits followed by the Add button then the single or multi-digit number must be stored before the textfield is cleared. The user can then click on more digits to make up a second number followed by the Equals button. Ater clicking on the Equais button the sum of the 2 selected numbersis (10) displayed in the textfield. 3.4 Write the Java statements for a class called RunCalculator, in which you declare a main method with Java statements to display the GUI. The dimensions of the frame are width 300 and height 300. Page 7 of 7

Answer 1

import javax.swing.*;

import java.awt.*;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

public class Frame extends JFrame {

private double tempNumbers1 = 0;

private double tempNumbers2 = 0;

private byte function = -1;

private JTextField resultJText;

public Frame() {

JButton[] numberButtons = new JButton[10];

for ( int i = 9; i >= 0; i--) {

numberButtons[i] = new JButton(Integer.toString(i));

}

JButton enterButton = new JButton("Enter");

JButton cButton = new JButton("C");

JButton multiplyButton = new JButton("*");

JButton divideButton = new JButton("/");

JButton addButton = new JButton("+");

JButton substractButton = new JButton("-");

resultJText = new JTextField();

resultJText.setPreferredSize(new Dimension(160, 20));

resultJText.setBackground(Color.WHITE);

resultJText.setEnabled(false);

resultJText.setHorizontalAlignment(4);

resultJText.setDisabledTextColor(Color.BLACK);

JPanel motherPanel = new JPanel();

motherPanel.setLayout(new BoxLayout(motherPanel, BoxLayout.Y_AXIS));

JPanel textPanel = new JPanel();

textPanel.setPreferredSize(new Dimension(160, 20));

textPanel.add(resultJText);

JPanel numberButtonsPanel = new JPanel();

numberButtonsPanel.setPreferredSize(new Dimension(160, 100));

for(int i = 9; i>=0; i--) {

numberButtonsPanel.add(numberButtons[i]);

}

JPanel functionButtonPanel = new JPanel();

functionButtonPanel.setPreferredSize(new Dimension(160, 35));

functionButtonPanel.add(enterButton);

functionButtonPanel.add(cButton);

functionButtonPanel.add(multiplyButton);

functionButtonPanel.add(divideButton);

functionButtonPanel.add(addButton);

functionButtonPanel.add(substractButton);

numberButtonsAction[] numberButtonActions = new numberButtonsAction[10];

for ( int i = 0; i < 10; i++ ) {

numberButtonActions[i] = new numberButtonsAction(numberButtons[i]);

numberButtons[i].addActionListener(numberButtonActions[i]);

}

EnterButton enter = new EnterButton();

enterButton.addActionListener(enter);

CButton c = new CButton();

cButton.addActionListener(c);

MultiplyButton multiply = new MultiplyButton();

multiplyButton.addActionListener(multiply);

DivideButton divide = new DivideButton();

divideButton.addActionListener(divide);

AddButton add = new AddButton();

addButton.addActionListener(add);

SubtractButton subtract = new SubtractButton();

substractButton.addActionListener(subtract);

motherPanel.add(textPanel);

motherPanel.add(numberButtonsPanel);

motherPanel.add(functionButtonPanel);

add(motherPanel);

setTitle("ButtonTest");

setSize(180, 290);

setLocationByPlatform(true);

setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);

setVisible(true);

}

private class numberButtonsAction implements ActionListener {

private String c;

public numberButtonsAction(JButton a) {

this.c = a.getText();

}

public void actionPerformed(ActionEvent e) {

if (!resultJText.getText().equals("0.0")) {

resultJText.setText(resultJText.getText() + c);

} else {

resultJText.setText("");

actionPerformed(e);

}

}

}

private class EnterButton implements ActionListener {

@Override

public void actionPerformed(ActionEvent e) {

tempNumbers2 = Double.parseDouble(resultJText.getText());

if (function == 0) {

resultJText.setText(Double.toString((Math.round((tempNumbers1 / tempNumbers2) * 100)) / 100));

} else if (function == 1) {

resultJText.setText(Double.toString(tempNumbers1 * tempNumbers2));

} else if (function == 2) {

resultJText.setText(Double.toString(tempNumbers2 + tempNumbers1));

} else if (function == 3) {

resultJText.setText(Double.toString(tempNumbers1 - tempNumbers2));

} else {

resultJText.setText(String.valueOf(tempNumbers1));

}

tempNumbers1 = Double.parseDouble(resultJText.getText());

}

}

private class CButton implements ActionListener {

@Override

public void actionPerformed(ActionEvent e) {

resultJText.setText("");

tempNumbers1 = 0;

tempNumbers2 = 0;

function = -1;

}

}

private class DivideButton implements ActionListener {

@Override

public void actionPerformed(ActionEvent e) {

if (tempNumbers1 == 0) {

tempNumbers1 = Double.parseDouble(resultJText.getText());

resultJText.setText("");

} else {

tempNumbers2 = Double.parseDouble(resultJText.getText());

resultJText.setText("");

}

function = 0;

}

}

private class MultiplyButton implements ActionListener {

@Override

public void actionPerformed(ActionEvent e) {

if (tempNumbers1 == 0) {

tempNumbers1 = Double.parseDouble(resultJText.getText());

resultJText.setText("");

} else {

tempNumbers2 = Double.parseDouble(resultJText.getText());

resultJText.setText("");

}

function = 1;

}

}

private class AddButton implements ActionListener {

@Override

public void actionPerformed(ActionEvent e) {

if (tempNumbers1 == 0) {

tempNumbers1 = Double.parseDouble(resultJText.getText());

resultJText.setText("");

} else {

tempNumbers2 = Double.parseDouble(resultJText.getText());

resultJText.setText("");

}

function = 2;

}

}

private class SubtractButton implements ActionListener {

@Override

public void actionPerformed(ActionEvent e) {

if (tempNumbers1 == 0) {

tempNumbers1 = Double.parseDouble(resultJText.getText());

resultJText.setText("");

} else {

tempNumbers2 = Double.parseDouble(resultJText.getText());

resultJText.setText("");

}

function = 3;

}

}

}