SWT.WRAP                自动调整label中的内容行以适应可见区域的大小（既label内容自动换行）
SWT.LEFT                   label内容左对齐
SWT.CENTER             label内容中间对齐
SWT.RIGHT                label内容右对齐
SWT.SEPARATOR      画一个分割符
SWT.HORIZONTAL   使分割符水平（仅在画分割符时使用）
SWT.VERTICAL         使分割符垂直（仅在画分割符时使用）
SWT.SHADOW_IN     使分割符有“SHADOW_IN ”的效果（仅在画分割符时使用）
SWT.SHADOW_OUT  使分割符有“SHADOW_OUT”的效果 （仅在画分割符时使用）

Label Events (none)

label是一个静态组件可用来放置文本，图像，分隔符，一个静态的控件既不含有焦点（focus）也不参与tab traversal，鼠标点击不产生任何影响

Label label = new Label(parent, SWT.NONE);
label.setText("User Name:");

Text and Images

label允许你设置文本或图像在上面如果你什么都不设置则label显示的是background color

setText(String string)    设置label显示文本内容string
getText()                      返回label的文本内容
setImage(Image image) 设置label显示的图像
getImage()                    返回图像

注意：文本和图像只能设置其中的一种，若你想在label上文本和图像都加入，你要使用CLabel

MarginLeft, MarginTop, MarginRight, MarginBottom and Spacing

前面4个是指定于边框距离的，spacing指定widget之间的间隔

   RowLayout rowLayout = new RowLayout();

   rowLayout.wrap = false;

   rowLayout.pack = false;

   rowLayout.justify = true;

   rowLayout.type = SWT.VERTICAL;

   rowLayout.marginLeft = 5;

   rowLayout.marginTop = 5;

   rowLayout.marginRight = 5;

   rowLayout.marginBottom = 5;

   rowLayout.spacing = 0;

   shell.setLayout(rowLayout)

下面的代码使用RowData对象来改变button的大小

import org.eclipse.swt.*;

import org.eclipse.swt.widgets.*;

import org.eclipse.swt.layout.*;

 

public class RowDataExample {

 

   public static void main(String[] args) {

       Display display = new Display();

       Shell shell = new Shell(display);

       shell.setLayout(new RowLayout());

       Button button1 = new Button(shell, SWT.PUSH);

       button1.setText("Button 1");

       button1.setLayoutData(new RowData(50, 40));

       Button button2 = new Button(shell, SWT.PUSH);

       button2.setText("Button 2");

       button2.setLayoutData(new RowData(50, 30));

       Button button3 = new Button(shell, SWT.PUSH);

       button3.setText("Button 3");

       button3.setLayoutData(new RowData(50, 20));

       shell.pack();

       shell.open();

       while (!shell.isDisposed()) {

          if (!display.readAndDispatch()) display.sleep();

       }

   }

}

 

参考：http://www.eclipse.org/articles/Understanding%20Layouts/Understanding%20Layouts.htm

  Button button0 = new Button (shell, SWT.PUSH);
  button0.setText ("button0");

  Button button1 = new Button (shell, SWT.PUSH);
  button1.setText ("button1");

  Button button2 = new Button (shell, SWT.PUSH);
  button2.setText ("button2");

  shell.pack ();
  shell.open ();

  while (!shell.isDisposed ()) {
   if (!display.readAndDispatch ())
    display.sleep ();
  }
  display.dispose ();
 }
}

参考：http://www.eclipse.org/articles/Understanding%20Layouts/Understanding%20Layouts.htm

Display display = new Display();
   Shell shell = new Shell(display);
   GridLayout gridLayout = new GridLayout();
   gridLayout.numColumns = 3;
   shell.setLayout(gridLayout);
   new Button(shell, SWT.PUSH).setText("B1");
   new Button(shell, SWT.PUSH).setText("Wide Button 2");
   new Button(shell, SWT.PUSH).setText("Button 3");
   new Button(shell, SWT.PUSH).setText("B4");
   new Button(shell, SWT.PUSH).setText("Button 5");
   shell.pack();
   shell.open();
   while (!shell.isDisposed()) {
      if (!display.readAndDispatch()) display.sleep();
   }
MakeColumnsEqualWidth
使每列的宽度相同，默认值为false

MarginWidth, MarginHeight, HorizontalSpacing, and VerticalSpacing
页边宽度，页边高度，水平间隔，垂直间隔

GridData
GridData是控制小部件布局的对象，例如
   GridData gridData = new GridData();
   gridData.horizontalAlignment = GridData.FILL;//horizontalAlignment是指水平对齐方式
//（有GEGINING，END，CENTRE，FILL）
   gridData.grabExcessHorizontalSpace = true;
   button1.setLayoutData(gridData);
注意：每个在GridLayout中的widget都有一个自己的GridData，如果没有为它设置则系统会给他一个默认的GridData！

HorizontalAlignment and VerticalAlignment

每个alignment域指定控件在它的格子单元内水平/垂直怎样对齐，他们是下面4个值中的一个

          ·      BEGINNING（左对齐）·      CENTER（中间对齐）·      END右对齐·      FILL充满格子

缺省值为horizontalAlignment is BEGINNING ， verticalAlignment is CENTER

www.apache.org

http://sourceforge.net/

public class BounceBall {

 private Shell sShell = null;  //  @jve:decl-index=0:visual-constraint="10,10"
 private Canvas canvas = null;
 private Button startButton = null;
 ballThread bt = null;
 Display display = null;

 public BounceBall() {
  super();
  // TODO Auto-generated constructor stub
//  bt = new ballThread(canvas);
  display = Display.getDefault();
 }

 /**
  * This method initializes canvas 
  *
  */
 private void createCanvas() {
  canvas = new Canvas(sShell, SWT.NONE);
  canvas.setBackground(new Color(Display.getCurrent(), 0, 0, 255));
  canvas.setBounds(new org.eclipse.swt.graphics.Rectangle(26,14,527,242));
 }

 /**
  * @param args
  */
 public static void main(String[] args) {
  // TODO Auto-generated method stub
  /* Before this is run, be sure to set up the launch configuration (Arguments->VM Arguments)
   * for the correct SWT library path in order to run with the SWT dlls.
   * The dlls are located in the SWT plugin jar. 
   * For example, on Windows the Eclipse SWT 3.1 plugin jar is:
   *       installation_directory\plugins\org.eclipse.swt.win32_3.1.0.jar
   */
//  Display display = Display.getDefault();
  
  BounceBall thisClass = new BounceBall();
  thisClass.createSShell();
  thisClass.sShell.open();

  while (!thisClass.sShell.isDisposed()) {
   if (!thisClass.display.readAndDispatch())
    thisClass.display.sleep();
  }
  thisClass.display.dispose();
 }

 /**
  * This method initializes sShell
  */
 private void createSShell() {
  sShell = new Shell();
  sShell.setText("Shell");
  createCanvas();
  sShell.setSize(new org.eclipse.swt.graphics.Point(588,367));
  startButton = new Button(sShell, SWT.NONE);
  startButton.setBounds(new org.eclipse.swt.graphics.Rectangle(87,284,76,33));
  startButton.setText("Start");
  startButton.addSelectionListener(new org.eclipse.swt.events.SelectionAdapter() {
   public void widgetSelected(org.eclipse.swt.events.SelectionEvent e) {
    //System.out.println("widgetSelected()"); // TODO Auto-generated Event stub widgetSelected()
    new ballThread(40,40,canvas).start();
    
   }
  });
 }

}

 class ballThread extends Thread {

  int x, y, xsize, ysize, addx, addy;
  Rectangle rc = null;
  GC gc = null;
  Canvas c = null;
  Color red = Display.getCurrent().getSystemColor(SWT.COLOR_RED);

  public ballThread(int x,int y,Canvas ca) {
   c = ca;
   this.x = x;
   this.y = y;
   xsize = 10;
   ysize = 10;
   addx = 1;
   addy = 2;
   rc = c.getBounds();
   
  }
  
  
  public void draw(int x, int y, int xsize, int ysize) {
   
   gc = new GC(c);
   gc.drawOval(x, y, xsize, ysize);
   gc.setBackground(red);
   gc.fillOval(x, y, xsize, ysize);
   gc.dispose();
  }

  public void clean() {
   gc = new GC(c);
   // Rectangle rt = canvas.getBounds();
   gc.drawRectangle(rc.x - 100, rc.y - 100, rc.width + 100,
     rc.height + 100);
   gc.fillRectangle(rc.x - 100, rc.y - 100, rc.width + 100,
     rc.height + 100);
   gc.dispose();
  }

  public void run() {
   for (int i = 1; i < 1500; i++) {
    try{
     
    Display.getDefault().asyncExec(new Thread () {
    public void run(){
    draw(x, y, xsize, ysize);}});
     Thread.sleep(10);
    
    Display.getDefault().asyncExec(new Thread () {
    public void run(){ 
    clean();}});
    } catch (InterruptedException e) {
     // TODO Auto-generated catch block
     e.printStackTrace();
    }
    

    if (rc.contains(x, y)) {
     x += addx;
     y += addy;
    } else {
     

     if (x >= rc.width || x <= 26) {
      addx = -addx;

      x += addx;
      y += addy;
     } else if (y >= rc.height || y <= 14) {
      addy = -addy;

      x += addx;
      y += addy;
     }

    }

   }
  }

 }

想到一个办法能够去除那些exceptions，就是在display.dispose()前加一句Thread.currentThread().stop();强制终止线程，不过这个办法肯定是最垃圾的办法.......