controlwindow.java

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

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class ControlWindow extends JFrame implements ActionListener {
    private JButton turnBtn, moveBtn;
    private Robot theRobot;
    
    /** post:   this window is created
     *          and getX() == 13*72+10  and getY()==20
     *          and getWidth() == 200  and  getHeight() == 120
     *          and theRobot == r  
     *          and turnBtn is created and placed on this
     *          and moveBtn is created and placed on this 
     */
    public ControlWindow(Robot r) {
        super("Control Buttons");
        setBounds(13*72+30, 20, 200, 120);
        getContentPane().setLayout(null);
        setVisible(true);
        theRobot = r;
        
        turnBtn = new JButton("Turn");
        turnBtn.setBounds(60, 10, 80, 30);
        turnBtn.addActionListener(this);
        getContentPane().add(turnBtn, 0);
        moveBtn = new JButton("Step");
        moveBtn.setBounds(60, 50, 80, 30);
        moveBtn.addActionListener(this);
        getContentPane().add(moveBtn, 0);
        repaint();
    }
    
    /** This is an event hanlder for both buttons.
     *  post:   e.getSource()==turnBtn implies postcondition of theRobot.rotateClockwise()
     *          and  e.getCourse==moveBtn implies postcondition of theRobot.moveByOneStep() 
     */
    public void actionPerformed(ActionEvent e)  {
        if (e.getSource() == turnBtn)
            theRobot.rotateClockwise();
        else if (e.getSource() == moveBtn)
            theRobot.moveByOneStep();
    }
}