滚动面板ScrolledComposite

import org.eclipse.swt.SWT;
import org.eclipse.swt.widgets.*;
import org.eclipse.swt.custom.ScrolledComposite;
import org.eclipse.swt.layout.*;
public class A{
	public static void main(String[] args){
		Display display=new Display();
		Shell shell=new Shell(display);
		shell.setText("滚动面板ScrolledComposite");
		//滚动面板：带有垂直滚动条和水平滚动条的面板
		FillLayout layout1=new FillLayout();
		layout1.marginHeight=20;
		layout1.marginWidth=20;
		shell.setLayout(layout1);//必须要有
		//shell.setLayout(new FillLayout(SWT.HORIZONTAL));//必须要有

		//创建一个滚动面板对象,有边框，水平滚动，垂直滚动
		ScrolledComposite sc=new ScrolledComposite(shell,SWT.H_SCROLL|SWT.V_SCROLL|SWT.BORDER);
		//创建一个普通的面板放在滚动面板中
		Composite c=new Composite(sc,SWT.NONE);
		
		GridLayout layout=new GridLayout();
		layout.numColumns=6;//列数是6
		c.setLayout(layout);
		
		for(int i=0;i<20;i++){
			Button bt=new Button(c,SWT.PUSH);
			bt.setText("按钮"+i);
			c.setSize(c.computeSize(SWT.DEFAULT, SWT.DEFAULT));
			//c.setSize(50,80);//错误的
		}
		
		//将普通面板设置为受控的滚动面板
		sc.setContent(c);
		//设置某一个控件受控于滚动面板的方法setContent(Control content)
		
		//打开窗口，进行窗口的显示
		shell.setSize(300,200);
		//shell.pack();
		shell.open();
		while(!shell.isDisposed()){
			//当窗口没有被释放的时候
			if(!display.readAndDispatch()){
				display.sleep();
			}		
		}
		display.dispose();
	}
}
import org.eclipse.swt.SWT;
import org.e