Four types of listeners (self class, external class, Inner class, anonymous class)

2. Import javax.swing.*;
4. Import java.awt.*;
6. Import java.awt.event.*;
10. Public class Thisclassevent extends JFrame implements actionlistener{
12. Public thisclassevent () {
14. SetLayout (new FlowLayout ());
16. JButton btn=New JButton ("OK");
18. Add (BTN);
20. Btn.addactionlistener (this);
22. }
24. public void actionperformed (ActionEvent e) {
26. System.out.println ("The OK button is clicked");
28. }
30. public static void Main (String args[]) {
32. Thisclassevent frame = new Thisclassevent ();
34. Frame.settitle ("Self-class as Event listener");
36. Frame.setlocationrelativeto (null); //Center the frame
38. Frame.setdefaultcloseoperation (Jframe.exit_on_close);
40. Frame.setsize (280, 100);
42. Frame.setvisible (true);
44. new Thisclassevent ();
46. }
48. }
52. Import java.awt.*;
54. Import java.awt.event.*;
56. Import javax.swing.*;
60. Public class Outerclassevent extends jframe{
62. Public outerclassevent () {
64. SetLayout (new FlowLayout ());
66. JButton btn=New JButton ("OK");
68. Add (BTN);
70. Outerclass btlistener=New Outerclass ();
72. Btn.addactionlistener (Btlistener);
74. }
76. public static void Main (String args[]) {
78. Outerclassevent frame = new Outerclassevent ();
80. Frame.settitle ("external class as Event listener");
82. Frame.setlocationrelativeto (null); //Center the frame
84. Frame.setdefaultcloseoperation (Jframe.exit_on_close);
86. Frame.setsize (280, 100);
88. Frame.setvisible (true);
90. new Thisclassevent ();
92. }
94. }
96. Class Outerclass implements actionlistener{
98. public void actionperformed (ActionEvent e) {
100. System.out.println ("The OK button is clicked");
102. }
104. }
108. Import java.awt.*;
110. Import java.awt.event.*;
112. Import javax.swing.*;
116. Class Innerclassevent extends jframe{
118. Public innerclassevent () {
120. SetLayout (new FlowLayout ());
122. JButton btn=New JButton ("OK");
124. Add (BTN);
126. Outerclass btlistener=New Outerclass ();
128. Btn.addactionlistener (Btlistener);
130. }
132. class Innerclass implements actionlistener{
134. public void actionperformed (ActionEvent e) {
136. System.out.println ("The OK button is clicked");
138. }
140. }
142. public static void Main (String args[]) {
144. Innerclassevent frame = new Innerclassevent ();
146. Frame.settitle ("inner class as Event listener");
148. Frame.setlocationrelativeto (null); //Center the frame
150. Frame.setdefaultcloseoperation (Jframe.exit_on_close);
152. Frame.setsize (280, 100);
154. Frame.setvisible (true);
156. new Thisclassevent ();
158. }
162. }
166. Import java.awt.*;
168. Import java.awt.event.*;
170. Import javax.swing.*;
174. Class Anonymousevent extends jframe{
176. Public anonymousevent () {
178. SetLayout (new FlowLayout ());
180. JButton btn=New JButton ("OK");
182. Add (BTN);
184. Btn.addactionlistener (
186. new ActionListener () { //anonymous inner class as parameter, new one lisenter actually creates a class that implements this listener
188. public void actionperformed (ActionEvent e) {
190. System.out.println ("The OK button is clicked");
192. }
194. }
196. );
198. }
200. public static void Main (String args[]) {
202. Anonymousevent frame = new Anonymousevent ();
204. Frame.settitle ("Anonymous internal class as Event listener");
206. Frame.setlocationrelativeto (null); //Center the frame
208. Frame.setdefaultcloseoperation (Jframe.exit_on_close);
210. Frame.setsize (280, 100);
212. Frame.setvisible (true);
214. new Thisclassevent ();
216. }
218. }

Four types of listeners (self class, external class, Inner class, anonymous class)