Frame f = new Frame();
        
        f.addWindowListener(new WindowListener() {

            @Override
            public void windowActivated(WindowEvent arg0) {
                // TODO Auto-generated method stub
                
            }

            @Override
            public void windowClosed(WindowEvent arg0) {
                // TODO Auto-generated method stub
                System.out.println("关闭");
            }

            @Override
            public void windowClosing(WindowEvent arg0) {
                // TODO Auto-generated method stub
                
            }

            @Override
            public void windowDeactivated(WindowEvent arg0) {
                // TODO Auto-generated method stub
                
            }

            @Override
            public void windowDeiconified(WindowEvent arg0) {
                // TODO Auto-generated method stub
                
            }

            @Override
            public void windowIconified(WindowEvent arg0) {
                // TODO Auto-generated method stub
                
            }

            @Override
            public void windowOpened(WindowEvent arg0) {
                // TODO Auto-generated method stub
                
            }
        });

------解决方案--------------------

开启F2的时候  设置F1 visible = false  
 开启F1的时候  设置F2 visible = false  


------解决方案--------------------
boolean flag标记一下。通过flag判断。