Making a calculator in Java, how to allow numeric inputs only

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DATE: Oct. 12, 2013, 10:06 p.m.

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  1. import java.awt.Color;
  2. import java.awt.FlowLayout;
  3. import java.awt.LayoutManager;
  4. import java.awt.TextField;
  6. import javax.swing.JButton;
  7. import javax.swing.JFrame;
  8. import javax.swing.JPanel;
  9. import javax.swing.JTextArea;
  10. import java.awt.event.ActionListener;
  11. import java.awt.event.ActionEvent;
  12. import java.text.ParseException;
  13. import java.util.Scanner;
  15. public class calculator_gui<reutrn> implements ActionListener {
  17. JFrame frame = new JFrame("Calculator");
  18. JPanel Panel = new JPanel (new java.awt.FlowLayout());
  20. JTextArea text = new JTextArea(1,20);
  21. JButton but1= new JButton("1");
  22. JButton but2= new JButton("2");
  23. JButton but3= new JButton("3");
  24. JButton but4= new JButton("4");
  25. JButton but5= new JButton("5");
  26. JButton but6= new JButton("6");
  27. JButton but7= new JButton("7");
  28. JButton but8= new JButton("8");
  29. JButton but9= new JButton("9");
  30. JButton but0= new JButton("0");
  33. JButton butadd= new JButton("+");
  34. JButton butsub= new JButton("-");
  35. JButton butmulti= new JButton("*");
  36. JButton butdiv= new JButton("/");
  37. JButton buteq= new JButton("=");
  38. JButton butclear= new JButton("C");
  40. Double number1,number2,result;
  41. int addc=0,subc=0,multic=0,divc=0;
  45. public void gui(){
  47. Panel.setLayout(FlowLayout());
  48. frame.setVisible(true);
  49. frame.setBounds(100, 100, 450, 285);
  50. frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  51. // frame.setResizable(false);
  53. frame.add(Panel);
  54. Panel.setBackground(Color.green);
  56. Panel.add(text);
  57. text.setBounds(10, 32, 361, 29);
  61. Panel.add(but1);
  62. but1.setBackground(Color.red);
  63. but1.setBounds(10, 81, 89, 23);
  65. Panel.add(but2);
  66. but2.setBounds(126, 81, 89, 23);
  68. Panel.add(but3);
  69. but3.setBounds(225, 81, 89, 23);
  71. Panel.add(but4);
  72. but4.setBounds(10, 115, 89, 23);
  74. Panel.add(but5);
  75. but5.setBounds(126, 115, 89, 23);
  77. Panel.add(but6);
  78. but6.setBounds(225, 115, 89, 23);
  80. Panel.add(but7);
  81. but7.setBounds(10, 149, 89, 23);
  83. Panel.add(but8);
  84. but8.setBounds(126, 149, 89, 23);
  86. Panel.add(but9);
  87. but9.setBounds(225, 149, 89, 23);
  89. Panel.add(but0);
  90. but0.setBounds(126, 183, 89, 23);
  92. Panel.add(butadd);
  93. butadd.setBounds(324, 81, 89, 23);
  95. Panel.add(butsub);
  96. butsub.setBounds(324, 115, 89, 23);
  98. Panel.add(butmulti);
  99. butmulti.setBounds(324, 183, 89, 23);
  101. Panel.add(butdiv);
  102. butdiv.setBounds(324, 149, 89, 23);
  104. Panel.add(buteq);
  105. buteq.setBounds(225, 183, 89, 23);
  107. Panel.add(butclear);
  108. butclear.setBounds(10, 183, 89, 23);
  114. but1.addActionListener(this);
  115. but2.addActionListener(this);
  116. but3.addActionListener(this);
  117. but4.addActionListener(this);
  118. but5.addActionListener(this);
  119. but6.addActionListener(this);
  120. but7.addActionListener(this);
  121. but8.addActionListener(this);
  122. but9.addActionListener(this);
  123. but0.addActionListener(this);
  124. butadd.addActionListener(this);
  125. butsub.addActionListener(this);
  126. butmulti.addActionListener(this);
  127. butdiv.addActionListener(this);
  128. buteq.addActionListener(this);
  129. butclear.addActionListener(this);
  136. }
  138. private LayoutManager FlowLayout() {
  139. // TODO Auto-generated method stub
  140. return null;
  141. }
  143. @Override
  144. public void actionPerformed(ActionEvent e){
  146. Object source = e.getSource();
  148. if(source==butclear){
  150. number1=0.0;
  151. number2=0.0;
  152. text.setText(null);
  154. }
  157. if(source==but1){
  158. text.append("1");
  160. }
  163. if(source==but2){
  164. text.append("2");
  166. }
  168. if(source==but3){
  169. text.append("3");
  171. }
  173. if(source==but4){
  174. text.append("4");
  176. }
  178. if(source==but5){
  179. text.append("5");
  181. }
  183. if(source==but6){
  184. text.append("6");
  186. }
  188. if(source==but7){
  189. text.append("7");
  191. }
  193. if(source==but8){
  194. text.append("8");
  196. }
  198. if(source==but9){
  199. text.append("9");
  201. }
  203. if(source==but0){
  204. text.append("0");
  206. }
  207. if(source==butadd){
  208. number1=number_reader();
  209. text.setText("");
  210. addc=1;
  211. subc=0;
  212. multic=0;
  213. divc=0;
  216. }
  218. if(source==butsub){
  219. number1=number_reader();
  220. text.setText("");
  221. addc=0;
  222. subc=1;
  223. multic=0;
  224. divc=0;
  227. }
  228. if(source==butmulti){
  229. number1=number_reader();
  230. text.setText("");
  231. addc=0;
  232. subc=0;
  233. multic=1;
  234. divc=0;
  237. }
  238. if(source==butdiv){
  239. number1=number_reader();
  240. text.setText("");
  241. addc=0;
  242. subc=0;
  243. multic=0;
  244. divc=1;
  247. }
  251. if(source==buteq){
  253. number2=number_reader();
  254. if(addc>0){
  255. result=number1+number2;
  256. text.setText(Double.toString(result));
  258. }
  260. if(subc>0){
  261. result=number1-number2;
  262. text.setText(Double.toString(result));
  263. }
  265. if(multic>0){
  266. result=number1*number2;
  267. text.setText(Double.toString(result));
  269. }
  274. }
  282. if(divc>0){
  283. result=number1/number2;
  284. text.setText(Double.toString(result));
  286. }
  289. }
  294. public double number_reader(){
  295. Double num1;
  296. String s;
  297. s=text.getText();
  298. num1=Double.valueOf(s);
  300. return num1;
  303. }
  308. }
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