public class myCanvas extends Canvas
{
........
public myCanvas (Composite arg0, int arg1)
{
///////////////
......
//////////////////返里的 new timer去掉，移到main里.
}

};
public class MyTask extends TimerTask
{

myCanvas c;
MyTask (myCanvas c)
{
super();
this.c = c;
}

public void run()
{

System.out.println("aaa");
c.redraw();
//每次运行到redraw 时总是显示 local variables unavailable
//不要redraw这一句就运行的很好,谁知道是为什么?


}
}
public class MainWnd {
public static void main (String [] args) {

Display display = new Display ();
final Shell shell = new Shell (display);

myCanvas v = new myCanvas(shell, SWT.CENTER);
///////////////////////////
Timer t = new Timer(true);
MyTask task = new MyTask (v);
t.schedule(task, 600, 200);
//////////////////////这里加了几句.

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