driver.java

Java程序设计(美) David D. Riley著 机械工业出版社 书籍配套 代码

/**	COLLEGE toggle Program  (Figure 7.13)
 *	Author: David Riley
 */
import java.awt.*;
public class Driver extends ThreeButtons {
	private ThreeButtonFrame window;
	private Label sweatshirtMsg;
	private boolean isAdded;
	/**post:	window is constructed 
	 *			and sweatshirtMsg.getText()=="COLLEGE"
	 *			and sweatshirtMsg has been added to window誷 content pane
	 *			and isAdded 
	 */
	public Driver()  {   
		window = new ThreeButtonFrame( "Flashing Message Window" );
		window.setLayout(null);
		sweatshirtMsg = new Label( "COLLEGE" );
		sweatshirtMsg.setBounds( 250, 200, 100, 30 );
		window.add(sweatshirtMsg, 0);
		isAdded = true;
		window.repaint();
	}
	
	/**pre:	sweatshirtMsg!=null  and  window!=null 
	 *	post:	(isAdded@pre  implies
	 *				sweatshirtMsg is removed and  not isAdded)
	 *			and  (not isAdded@pre  implies
	 *				sweatshirtMsg is added and isAdded) 
	 */
	public void leftAction()   {
		if ( isAdded )   {
			window.remove( sweatshirtMsg );
		} else {
			window.add( sweatshirtMsg, 0 );
		}
		window.repaint();
		isAdded = !isAdded;
	}
    
	public void midAction()   {
	}
	public void rightAction()   {
	}
}