在此组件构造函数之外为某些swing组件添加KeyListener对象时，KeyAdapter不起作用

    public class ActionViewer extends SimpleViewer
                              implements ActionListener

    {
        public ActionViewer(Dimension __wndSize, String pgnPath, 
                            PerspectiveProjection __persp)
        {
            super(__wndSize, pgnPath, __persp);

            ...
            cMng=null;
            ...
        }
        ///
        public void setCamera(double xMin, double xMax,
                              double yMin, double yMax,
                              double zMin, double zMax)
        {
            if(!isCameraInit())
            {
                if(cMng==null)
                    cMng=new CameraControl();
                this.addKeyListener((KeyListener)cMng);
                fCamInit=true;
            }
            setCameraBounds(xMin, xMax, yMin, yMax, zMin, zMax);
        }
    ...
}

...
ActionViewer scene = new ActionViewer(wndSize, pgnPath, persp);
scene.setCamera(xMin, xMax, yMin, yMax, zMin, zMax);
...