最近在实现一个图片压缩的功能，想在Eclipse.org上看有没有办法能够通过SWT的API能够改变图片的分辨率，Eclipse.org上面提供了好些SWT的例子，发现了Display的post方法挺有趣的，以前没有注意到，现在赶快把它记录下来，post方法的参数为Event，通过制定这个Events的属性，可以控制系统的键盘事件，比如保持shift键一直按着。下面是代码：
1 import org.eclipse.swt.*;
2 import org.eclipse.swt.widgets.*;
3
4 /**
5 * 触发系统的键盘事件 。
6 * @author vwpolo
7 * <p>2009-6-1</p>
8 */
9 public class Snippet146 {
10
11 public static void main(String[] args) {
12 final Display display = new Display();
13 final Shell shell = new Shell(display);
14 final Text text = new Text(shell, SWT.BORDER);
15 text.setSize(text.computeSize(150, SWT.DEFAULT));
16 shell.pack();
17 shell.open();
18 new Thread(){
19 public void run(){
20 String string = "Love the method.";
21 for (int i = 0; i < string.length(); i++) {
22 char ch = string.charAt(i);
23 boolean shift = Character.isUpperCase(ch);
24 ch = Character.toLowerCase(ch);
25 if (shift) {
26 Event event = new Event();
27 event.type = SWT.KeyDown;
28 event.keyCode = SWT.SHIFT;
29 display.post(event);
30 }
31 Event event = new Event();
32 event.type = SWT.KeyDown;
33 event.character = ch;
34 display.post(event);
35 try {
36 Thread.sleep(10);
37 } catch (InterruptedException e) {}
38 event.type = SWT.KeyUp;
39 display.post(event);
40 try {
41 Thread.sleep(100);
42 } catch (InterruptedException e) {}
43 if (shift) {
44 event = new Event();
45 event.type = SWT.KeyUp;
46 event.keyCode = SWT.SHIFT;
47 display.post(event);
48 }
49 }
50 }
51 }.start();
52 while (!shell.isDisposed()) {
53 if (!display.readAndDispatch()) display.sleep();
54 }
55 display.dispose();
56 }
57 }
上面的例子功能是演示在一个文本框中模拟用户输入一段字符串，字符串的内容是"Love the method.",还可以通过这个来移动鼠标的箭头，像下面这样：
1 public static void main(String[] args) {
2 final Display display = new Display();
3 final Shell shell = new Shell(display);
4 final Button button = new Button(shell,SWT.NONE);
5 button.setSize(100,100);
6 button.setText("Click");
7 shell.pack();
8 shell.open();
9 button.addListener(SWT.MouseDown, new Listener() {
10 public void handleEvent(Event e){
11 System.out.println("Mouse Down (button: " + e.button + " x: " + e.x + " y: " + e.y + ")");
12 }
13 });
14 final Point pt = display.map(shell, null, 50, 50);
15 new Thread(){
16 Event event;
17 public void run(){
18 try {
19 Thread.sleep(300);
20 } catch (InterruptedException e) {}
21 event = new Event();
22 event.type = SWT.MouseMove;
23 event.x = pt.x;
24 event.y = pt.y;
25 display.post(event);
26 try {
27 Thread.sleep(300);
28 } catch (InterruptedException e) {}
29 event.type = SWT.MouseDown;
30 event.button = 1;
31 display.post(event);
32 try {
33 Thread.sleep(300);
34 } catch (InterruptedException e) {}
35 event.type = SWT.MouseUp;
36 display.post(event);
37 }
38 }.start();
39 while (!shell.isDisposed()) {
40 if (!display.readAndDispatch()) display.sleep();
41 }
42 display.dispose();
43 }
首先创建一个100*100大小的按钮，然后通过display.map(shell, null, 50, 50);这段代码获得指定shell上的相对坐标，这里是指shell的相对坐标上的x=50,y=50，然后再换算成显示屏幕系统的绝对坐标，设置事件类型为鼠标移动，移动的目标坐标位置是刚才我们取得的系统坐标
event = new Event();
event.type = SWT.MouseMove;
event.x = pt.x;
event.y = pt.y;
display.post(event);
在触发这个事件后，让它休眠0.3秒
try {
Thread.sleep(300);
} catch (InterruptedException e) {}
接着再将事件的类型设置为鼠标按下事件：
event.type = SWT.MouseDown;
event.button = 1;
display.post(event);
这样就基本上模拟出了系统鼠标的动作了。大家有兴趣可以研究一下，比如用它来做点坏事情,呵呵