java Swing 按钮不显示、鼠标滑过才显示

万蕊科技

1. import javax.swing.*;
   
2. 
   ; \$ `2 K3 A$ n, T0 i
3. import java.awt.*;
   
4. import java.awt.event.*;
   $ o' Y$ H7 u" F; p
5. import java.awt.image.ImageObserver;
   
6. 
   ! F+ E# h! L& W4 z1 o
7. public class Welcome extends JFrame{
   
8. /**
   . T7 {+ w8 t/ \; r" V  \( H
9. *
   6 ~& P" m, ?9 \# e/ {
10. */
    
11. private static final long serialVersionUID = 1L;
    ' T3 q. _6 y# n& b: V2 B
12. /**
    : X, P; w, r2 ?/ d6 p8 z4 @
13. *
    0 X4 q& A3 p! W" Z2 J, {# n
14. */
    : Q# W% ^) g" w
15. private JButton JB,JB1,JB2,JB3;
    
16. private JLabel JL;
    ) _2 R" {3 M5 h& L- ?# Y
17. private Image img;
    3 o; A9 \+ }8 j4 f
18. private Toolkit tool;
    
19. 
    
20. Welcome(){
    ' \; i) _- y6 U
21. super("欢迎来到科帮网");
    ) k/ z# k: o* z$ b
22. setSize(600,500);
    / D* v+ o4 q3 _8 g) p
23. setLocation(250, 150);
    
24. Container container = getContentPane();
    ) u4 ?8 Y* v3 U. I" b- }/ ~
25. tool = getToolkit();
    4 t) e' D* y. h1 c
26. container.setLayout(null);
    
27. 
    3 i0 ]1 k: \/ q( @. v
28. JB = new JButton("查询学校景点信息");
    
29. JB1 = new JButton("查询2景点间的最短距离");
    
30. JB2 = new JButton("查询旅游路线");
    
31. JB3 = new JButton("退出");
    ' ?2 c: M4 F1 t$ Y& X  D
32. JL = new JLabel("欢迎使用校园导游咨询系统");
    / Z% g$ Y4 |( h$ [/ Z
33. img = tool.getImage("E://School.jpg");
    9 e* k+ @  }: g# m3 ~! e
34. 
    
35. JB.addActionListener(new MyMonitor());
    1 ?5 }% f5 {; @* Z, Y  |
36. JB1.addActionListener(new MyMonitor());
    5 a4 |3 P% O6 A6 j! u, h$ v  w% V& Q
37. JB2.addActionListener(new MyMonitor());
    % F2 W7 W+ }% H! F: E+ r
38. JB3.addActionListener((new MyMonitor()));
    
39. 
    
40. JL.setBounds(180, 20, 300, 40);
    7 X: T% O* r+ Q5 r5 c9 p
41. JB.setBounds(200, 60, 200, 30);
    
42. JB1.setBounds(200, 100, 200, 30);
    
43. JB2.setBounds(200, 140,200, 30);
    " }! G6 \3 p1 }6 y
44. JB3.setBounds(500, 400, 90, 30);
    
45. 
    
46. 
    
47. container.add(JB);
    
48. container.add(JB1);
    
49. container.add(JB2);
    
50. container.add(JB3);
    / f; E; M# w; r9 \
51. container.add(JL);
    ' G6 ^! x+ _4 r3 |. B  |
52. 
    
53. setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    
54. setVisible(true);
    ' b# o1 m6 [2 O- T4 j( G  h
55. 
    
56. }
    9 S8 Z9 i6 `# Q+ a. a4 M( i
57. 
    4 h: P6 k/ `( _& o1 ]9 y2 F" q7 j
58. private class MyMonitor implements ActionListener{
    - J: A, a7 i0 f: H3 v7 B
59. 
    7 n- I& |5 e( G$ I  u( J
60. public void actionPerformed(ActionEvent e) {
    
61. if(e.getSource()==JB){
    ' j- A: e8 T& y& l' M5 |/ ?; r% [( U
62. new MyGraphy();
    2 J. ~$ p; U+ D
63. setVisible(false);
    
64. }
    
65. if(e.getSource()==JB1){
    
66. new ShowLength();
      u( O! N4 h. v3 ^$ F; K( F
67. setVisible(false);
    
68. }
    
69. if(e.getSource()==JB2){
    
70. new ShowView();
    
71. setVisible(false);
    + z+ O5 {% ?& x+ M
72. }
    . Z; v7 K) G6 e7 z5 q3 Z! @9 J
73. 
    " B8 w! u5 e$ O5 A4 j
74. if(e.getSource()==JB3){
    
75. System.exit(0);
    ! w" f# z/ o8 _) F
76. }
    7 c/ u8 N" C2 G' X: ~! a
77. 
    % O& H2 s9 S4 x9 T6 b1 R" u3 [
78. }
    5 F# W% e# _1 S% y& _) u- ]: H
79. 
    
80. }
    
81. 
    - k$ T" ~; Y/ I6 M/ N
82. public void paint(Graphics g){
    . x$ A0 d- m1 P1 v" M
83. g.drawImage(img, 100, 230, 400, 250, (ImageObserver) this);
    
84. 
    
85. }
    
86. 
    * T: o* z' i% N& m" T
87. 
    
88. public static void main(String[] args) {
    
89. new Welcome();
    
90. }
    
91. }
    

复制代码

原因：paint方法被你重写了，但是你没处理好、所以要在 paint 方法前加super.paint(g)
( Z! K9 G" _6 T4 Z( J

java宫城大师

+ T$ K: f) R+ M7 c: {3 v下来，学习一下。谢谢

woniu

这个项目太棒勒！下下来学习下！

wudizxt

不错不错不错不错

wudizxt

不错不错不错