J2ME GUI实战之五 ----------LWUIT的绘图功能

<script>function StorePage(){d=document;t=d.selection?(d.selection.type!='None'?d.selection.createRange().text:''):(d.getSelection?d.getSelection():'');void(keyit=window.open('http://www.365key.com/storeit.aspx?t='+escape(d.title)+'&u='+escape(d.location.href)+'&c='+escape(t),'keyit','scrollbars=no,width=475,height=575,left=75,top=20,status=no,resizable=yes'));keyit.focus();}</script>本文来自：http://blog.csdn.net/hellogv/ ，转载必须注明出处！
首先先给出本例的效果图：


首先，需要说明一下LWUIT的控件：
LWUIT的控件，可以算是做得很全，他的设计模式跟J2SE有点类似，而做过J2ME的人要掌握也不需要长时间。LWUIT的控件，是原来高级控件与低级控件的集合，并加入了更多元素，因此你可以在用高级控件的同时，很自然地实现低级控件的功能。例如本文中的绘图功能，就是如此！
在本例中，依然使用大家熟悉的void paint(Graphics g) 函数，作为绘图的主体，然而paint的“上司”(绘图类)并不再是继承Canvas，而是继承Component，并且继承Component之后要这 样被调用：form.addComponent(BorderLayout.CENTER, new Painting());//Painting就是“上司”。可见，在LWUIT里，已经没低级控件这个概念，但是有这个用法-----传统的绘图类也作为控件类，被调用了。或许，你想用回原来的javax.microedition.lcdui.Graphics，但是lcdui的Graphics和Display 与 LWUIT的Graphics和Display不兼容(LWUIT多了很多方法)，因此“新欢旧爱不能兼得”！

OK,先给出调用绘图功能的代码：

1. privateclassButtonActionListenerimplementsActionListener{
2. publicvoidactionPerformed(ActionEventevt){
3. Stringsel_button=((Button)(evt.getSource())).getText();//取得所选按钮的名称
4. if(sel_button.equals("Image1"))
5. newAnimationDemo().form.show();
6. elseif(sel_button.equals("Image2"))
7. newPaintingDemo().form.show();
8. }
9. }

接着再给出绘图功能实现的代码：

1. /*
2. *Copyright?2008SunMicrosystems,Inc.Allrightsreserved.
3. *Useissubjecttolicenseterms.
4. *
5. */
6. packagecom.sun.lwuit.uidemo;
7. 
   
8. importcom.sun.lwuit.Command;
9. importcom.sun.lwuit.Component;
10. importcom.sun.lwuit.Form;
11. importcom.sun.lwuit.Graphics;
12. importcom.sun.lwuit.events.ActionEvent;
13. importcom.sun.lwuit.events.ActionListener;
14. importcom.sun.lwuit.layouts.BorderLayout;
15. 
    
16. 
    
17. /**
18. *Demonstratessimpleanimationbothstaticandmanual
19. *
20. *@authorShaiAlmog
21. */
22. publicclassPaintingDemoextendsFormimplementsActionListener{
23. publicFormform=newForm("PaintingDemo");
24. privateCommandbackCommand=newCommand("Back",1);
25. privateCommandnextCommand=newCommand("next",2);
26. PaintingDemo()
27. {
28. form.addCommand(backCommand);
29. form.addCommand(nextCommand);
30. form.setCommandListener(this);
31. form.setLayout(newBorderLayout());
32. form.addComponent(BorderLayout.CENTER,newPainting());
33. 
    
34. }
35. publicclassPaintingextendsComponent{
36. privateintw;
37. publicvoidpaint(Graphicsg){
38. g.setColor(0x000000);
39. g.fillRect(0,0,this.getWidth(),this.getHeight());
40. w=getWidth();
41. drawSqrt1(g);
42. g.setColor(0xffffff);
43. g.drawString("hellogv",12,33);
44. 
    
45. }
46. privatevoiddrawSqrt1(Graphicsg){
47. longstart=System.currentTimeMillis();
48. 
    
49. intcenterY1=50;
50. 
    
51. //绘制X轴
52. //设置绘图颜色为蓝色
53. g.setColor(0x0000FF);
54. g.drawLine(0,centerY1,w,centerY1);
55. 
    
56. //设置绘图颜色为白色
57. g.setColor(0xFFFFFF);
58. intoldX=0;
59. intoldY1=centerY1;
60. 
    
61. inty1;
62. for(inti=1;i<w;i++){
63. //放大3倍
64. y1=centerY1-(int)(3*Math.sqrt(i));
65. g.drawLine(oldX,oldY1,i,y1);
66. oldX=i;
67. oldY1=y1;
68. }
69. longtime=System.currentTimeMillis()-start;
70. System.out.println("drawSqrt1Runtime:"+time);
71. }
72. 
    
73. }
74. publicvoidactionPerformed(ActionEventarg0){
75. if(arg0.getCommand()==backCommand)
76. {
77. UIDemoMIDlet.backToMainMenu();
78. }
79. elseif(arg0.getCommand()==nextCommand)
80. {
82. }
83. }
84. }

OK，还是那句，希望大家多多支持LWUIT，让它可以做得更加好！