Linux下PasswordField暫時無法輸入

今天做練習時遇到的問題： 

1. import javax.swing.*;
2. import java.awt.*;
3. import java.awt.event.ActionEvent;
4. import java.awt.event.ActionListener;
5. /*@author HuangYangyang
6. *@version 2012.11.15
7. * */
8. publicclass BankTest {
9. JTextField userNameInput;
10. JPasswordField userPasswordInput;
11. JFrame loginFrame;
12. JFrame userCenter;
13. JTextField inputValue;
14. int pwNumber;
15. boolean accountLock;
16. boolean accountError = true;
17. boolean passwordError = true;
18. boolean success;
19. boolean exceptionB;
20. boolean exceptionT;
21. staticfinallong TOP = 10000;
22. long userDeposit =50000;
23. publicvoid setLoginGui(){
24. loginFrame = new JFrame();
25. loginFrame.setTitle("Bank Login");
26. JLabel userNameLabel = new JLabel(" Account ");
27. userNameInput = new JTextField(15);
28. JLabel userPasswordLabel = new JLabel("Password");
29. userPasswordInput = new JPasswordField(15);
30. JButton loginSubmit = new JButton("submit");
31. JButton loginClear = new JButton("reset");
32. JPanel panel01 = new JPanel();
33. panel01.add(new JLabel("Bank Login" ));
34. JPanel panel02 = new JPanel();
35. panel02.add(userNameLabel);
36. panel02.add(userNameInput);
37. JPanel panel03 = new JPanel();
38. panel03.add(userPasswordLabel);
39. panel03.add(userPasswordInput);
40. JPanel panel04 = new JPanel();
41. panel04.add(loginSubmit,BorderLayout.WEST);
42. panel04.add(loginClear,BorderLayout.EAST);
43. loginFrame.add(panel01,BorderLayout.NORTH);
44. loginFrame.add(panel02);
45. loginFrame.add(panel03);
46. JPanel panel05 = new JPanel();
47. panel05.add(panel02);
48. panel05.add(panel03);
49. loginFrame.add(panel04,BorderLayout.SOUTH);
50. loginFrame.add(panel05,BorderLayout.CENTER);
51. loginFrame.setLocationRelativeTo(null);
52. loginFrame.setSize(320,240);
53. loginFrame.setVisible(true);
54. loginSubmit.addActionListener(new SubmitAction());
55. loginClear.addActionListener(new ClearAction());
56. }
57. class SubmitAction implements ActionListener{
58. publicvoid actionPerformed(ActionEvent event){
59. checkUser();
60. }
61. }
62. class ClearAction implements ActionListener{
63. publicvoid actionPerformed(ActionEvent event){
64. userNameInput.setText("");
65. userPasswordInput.setText("");
66. }
67. }
68. privateenum OutAccount{
69. S10699371,SABER14192,WANGYU3
70. }
71. privateenum OutPassword{
72. S1419238911,s1419238912,SABERANIMEHTC3
73. }
74. publicvoid checkUser(){
75. String middlePassword = "";
76. String middleUser = userNameInput.getText();
77. char [] password = userPasswordInput.getPassword();
78. for(char a : password){
79. middlePassword =middlePassword + a;
80. }
81. String middleEnumUser = "";
82. String middleEnumPassword = "";
83. for(OutAccount a : OutAccount.values()){
84. middleEnumUser = a.toString();
85. if(middleEnumUser.equals(middleUser + middleEnumUser.charAt(middleEnumUser.length() - 1))){
86. accountError = false;
87. break;
88. }
89. }
90. for(OutPassword a : OutPassword.values()){
91. middleEnumPassword = a.toString();
92. if(middleEnumPassword.equals(middlePassword + middleEnumPassword.charAt(middleEnumPassword.length() - 1))){
93. passwordError = false;
94. break;
95. }
96. }
97. if(accountError == false & passwordError == false & middleEnumPassword.charAt(middleEnumPassword.length() - 1) == middleEnumUser.charAt(middleEnumUser.length() - 1)){
98. loginFrame.dispose();
99. setBankCenterGui();
100. }
101. elseif(accountError == true){
102. JOptionPane.showMessageDialog(null, "Account error!");
103. userNameInput.setText("");
104. userPasswordInput.setText("");
105. }
106. elseif(accountError == false & passwordError == true){
107. if(pwNumber == 3){
108. JOptionPane.showMessageDialog(null,"Account locked!");
109. loginFrame.dispose();
110. }
111. else{
112. JOptionPane.showMessageDialog(null,"Password error! Pealse check password!");
113. userPasswordInput.setText("");
114. pwNumber = pwNumber + 1;
115. }
116. }
117. else{
118. JOptionPane.showMessageDialog(null,"Account or Password error!");
119. userNameInput.setText("");
120. userPasswordInput.setText("");
121. }
122. }
123. privatevoid setBankCenterGui() {
124. userCenter = new JFrame("Bank Center");
125. JPanel panel01 = new JPanel();
126. panel01.add(new JLabel("Bank Center"));
127. JPanel panel02 = new JPanel();
128. inputValue = new JTextField(5);
129. panel02.add(inputValue);
130. JButton outputDeposit = new JButton("Withdrawal");
131. panel02.add(outputDeposit);
132. JButton inputDeposit = new JButton(" Deposit ");
133. panel02.add(inputDeposit);
134. userCenter.add(BorderLayout.NORTH,panel01);
135. userCenter.add(BorderLayout.CENTER,panel02);
136. outputDeposit.addActionListener(new InputDepositAction());
137. inputDeposit.addActionListener(new OutputDepositAction());
138. userCenter.setLocationRelativeTo(null);
139. userCenter.setSize(350,200);
140. userCenter.setVisible(true);
141. }
142. class OutputDepositAction implements ActionListener{
143. publicvoid actionPerformed(ActionEvent event){
144. setOutput();
145. JOptionPane.showMessageDialog(null,"Deposit success!");
146. inputValue.setText("");
147. }
148. }
149. class InputDepositAction implements ActionListener{
150. publicvoid actionPerformed(ActionEvent event){
151. try {
152. setInput();
153. } catch (BalanceLackException e) {
154. e.printStackTrace();
155. } catch (OverTopException e) {
156. e.printStackTrace();
157. }
158. finally{
159. if(success){
160. JOptionPane.showMessageDialog(null,"Withdrawal success!");
161. success = false;
162. inputValue.setText("");
163. }
164. else{
165. JOptionPane.showMessageDialog(null,"Withdrawal failed!");
166. if(exceptionB){
167. BalanceLackException.tip();
168. }
169. elseif(exceptionT){
170. OverTopException.tip();
171. }
172. inputValue.setText("");
173. }
174. }
175. }
176. }
177. publicvoid setOutput(){
178. long middleValue = Long.parseLong(inputValue.getText());
179. userDeposit = userDeposit + middleValue;
180. JOptionPane.showMessageDialog(null,"Deposit success !");
181. }
182. publicvoid setInput() throws BalanceLackException , OverTopException{
183. long middleValue = Long.parseLong(inputValue.getText());
184. if(userDeposit - middleValue < 0 )
185. exceptionB = true;
186. if(Long.parseLong(inputValue.getText()) > 30000)
187. exceptionT = true;
188. if(userDeposit - middleValue > 0 & Long.parseLong(inputValue.getText()) < 30000 ){
189. userDeposit = userDeposit - middleValue;
190. success = true;
191. }
192. }
193. publicstaticvoid main(String [] args){
194. BankTest go = new BankTest();
195. go.setLoginGui();
197. }
198. }

Linux下PasswordField無法輸入，只有把光標從密碼框移開，讓密碼框重新獲得焦點，可以輸入了。一開始以為是java的bug。後來知道是因為PasswordField組件默認不獲取系統輸入法支持，需要自己設置。

加入 userPasswordInput.enableInputMethods(true);    運行程序ok，可以輸入了。

詳見文檔說明：

By default, JPasswordField disables input methods; otherwise, input characters could be visible while they were composed using input methods. If an application needs the input methods support, please use the inherited method, enableInputMethods(true).