This tutorial will teach you how to make a simple calculator using Java Eclipse.
First Step : you must extends the JFrame and implements ActionListener .I have attached the video tutorial below it will help you to do this step by step.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 | import java.awt.EventQueue; import javax.swing.JFrame; import javax.swing.JLabel; import java.awt.Font; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import javax.swing.JPanel; import javax.swing.JTextField; import javax.swing.JButton; import java.awt.Color; public class Cal extends JFrame implements ActionListener { private JFrame frame; private JTextField txtnum1; private JTextField txtnum2; JLabel lblresult; JButton btnAdd; JButton btnMin; JButton btnSub; JButton btnDiv; private int operation; private JLabel lblResult; /** * Launch the application. */ public static void main(String[] args) { EventQueue.invokeLater(new Runnable() { public void run() { try { Cal window = new Cal(); window.frame.setVisible(true); } catch (Exception e) { e.printStackTrace(); } } }); } /** * Create the application. */ public Cal() { initialize(); } /** * Initialize the contents of the frame. */ private void initialize() { frame = new JFrame(); frame.setBounds(100, 100, 509, 370); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.getContentPane().setLayout(null); JLabel lblNewLabel = new JLabel("Calculator"); lblNewLabel.setFont(new Font("Trajan Pro", Font.BOLD, 35)); lblNewLabel.setBounds(119, 11, 283, 38); frame.getContentPane().add(lblNewLabel); JPanel panel = new JPanel(); panel.setBounds(43, 73, 402, 184); frame.getContentPane().add(panel); panel.setLayout(null); txtnum1 = new JTextField(); txtnum1.setFont(new Font("Tahoma", Font.BOLD, 13)); txtnum1.setBounds(207, 38, 153, 20); panel.add(txtnum1); txtnum1.setColumns(10); txtnum2 = new JTextField(); txtnum2.setFont(new Font("Tahoma", Font.BOLD, 13)); txtnum2.setBounds(207, 84, 158, 20); panel.add(txtnum2); txtnum2.setColumns(10); JLabel lblNewLabel_1 = new JLabel("Number 1"); lblNewLabel_1.setFont(new Font("Tahoma", Font.BOLD, 14)); lblNewLabel_1.setBounds(38, 41, 102, 14); panel.add(lblNewLabel_1); JLabel lblNumber = new JLabel("Number 2"); lblNumber.setFont(new Font("Tahoma", Font.BOLD, 14)); lblNumber.setBounds(38, 87, 102, 14); panel.add(lblNumber); btnAdd = new JButton("+"); btnAdd.setBounds(10, 126, 89, 47); panel.add(btnAdd); btnMin = new JButton("-"); btnMin.setBounds(109, 126, 89, 47); panel.add(btnMin); btnSub = new JButton("*"); btnSub.setBounds(207, 126, 89, 47); panel.add(btnSub); btnDiv = new JButton("/"); btnDiv.setBounds(303, 126, 89, 47); panel.add(btnDiv); btnAdd.addActionListener(this); btnMin.addActionListener(this); btnSub.addActionListener(this); btnDiv.addActionListener(this); lblresult = new JLabel("New label"); lblresult.setForeground(Color.RED); lblresult.setFont(new Font("Times New Roman", Font.BOLD, 24)); lblresult.setBounds(260, 276, 120, 28); frame.getContentPane().add(lblresult); lblResult = new JLabel("Result"); lblResult.setFont(new Font("Times New Roman", Font.BOLD, 22)); lblResult.setBounds(164, 276, 120, 28); frame.getContentPane().add(lblResult); } public void getTotal(int operation) { if(txtnum1.getText().length()!=0 && txtnum2.getText().length()!=0) { switch(operation) { case 1: lblresult.setText(""+(Double.parseDouble(txtnum1.getText()) + Double.parseDouble(txtnum2.getText()))); break; case 2: lblresult.setText(""+(Double.parseDouble(txtnum1.getText() ) - Double.parseDouble(txtnum2.getText()))); break; case 3: lblresult.setText(""+(Double.parseDouble(txtnum1.getText()) * Double.parseDouble(txtnum2.getText()))); break; case 4: lblresult.setText(""+(Double.parseDouble(txtnum1.getText()) / Double.parseDouble(txtnum2.getText()))); break; } } } public void actionPerformed(ActionEvent ae) { if(ae.getSource()==btnAdd) { operation=1; getTotal(operation); } else if(ae.getSource()==btnMin) { operation=2; getTotal(operation); } else if(ae.getSource()==btnSub) { operation=3; getTotal(operation); } else if(ae.getSource()==btnDiv) { operation=4; getTotal(operation); } } } |
