ElevatorSimulation

这两天在做一个模拟电梯的程序

通常的办法在Elevator class上直接Paint出电梯来，通过设定Upper left corner 的位置来实现电梯的移动.

但是因为想到如果要给电梯加两个门~~也就是电梯上下人的时候，门开启后关闭。

设想1：改写结构，分离出一个ElevatorRec class，将这个JPanel add在Elevator上，然后再add两个JPanel做门在ElevatorRec上，在尝试了一段时间后.....失败的原因在于Java没有一个manually 设定 JPanel位置的机制，只有一些Layout manager不足以模拟电梯的移动。

设想2: 不改写结构，依然在原基础上，多画两个门，但问题出现了：画静态的门容易，画动态的门就难了，什么机制来控制门开和关呢?最初导致着手设想1的原因就是为了让ElevatorRec本身Implements ActionListener这样就能很容易的控制门的开关。如今看来只好使用Flag来实现，也就是在Elevator的PaintComponent()里面写入一个If 判断句，是否开启、关闭门。

但是问题依然存在，一个if判断句无法Control门的开关速度！也就是说，如果门开的慢了，电梯都开始移动了，门还没开启！或者门没有完全关闭，电梯就移动了！

如何解决，仍然在思考中....



好吧，解决的方法异常简单....代码如下：

/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
package Lab1;

/**
*
* @author tony
*/
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
//The main class
//The ButtonPanel class receives and handles button pressing events
public class Elevator_Simulation extends JFrame {

public JLabel state = new JLabel("");
; // display the state of the elevator
private JLabel id; //your name and group
public ButtonPanel control = new ButtonPanel(); //the button control panel
private Elevator elevator = new Elevator(this); // the elevator area
public JSlider slider;
public int cSpeed = 10;

public Elevator_Simulation() {
// Create GUI

id = new JLabel("Name: Zhang Shuhao Group:SE1 ");

slider = new JSlider(1, 2, 20, 10);

slider.setMajorTickSpacing(2);
slider.setMinorTickSpacing(1);

slider.setPaintTicks(true);
slider.setPaintLabels(true);

slider.addChangeListener(new ChangeListener() {

public void stateChanged(ChangeEvent evt) {
cSpeed = slider.getValue();
}
});

Container container = getContentPane();
container.setLayout(new BorderLayout());

container.add(id, BorderLayout.NORTH);
container.add(control, BorderLayout.WEST);
container.add(elevator, BorderLayout.CENTER);
container.add(state, BorderLayout.SOUTH);
container.add(slider, BorderLayout.EAST);

}

// Main method
public static void main(String[] args) {
// Create a frame and display it

Elevator_Simulation frame = new Elevator_Simulation();

frame.setTitle("Elevator_Simulation");
frame.setSize(600, 600);
frame.setVisible(true);

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

}
} //the end of Elevator_Simulation class
class ButtonPanel extends JPanel {

public JButton b[] = new JButton[8]; // 8 Buttons
public boolean bp[] = new boolean[8]; // the state of each button, pressed or not

public ButtonPanel() { //create GUI

this.setLayout(new GridLayout(8, 1));

ButtonListener btListener = new ButtonListener();

for (int i = 8; i >= 1; i--) {
b[i - 1] = new JButton("F" + i);
bp[i - 1] = false;
this.add(b[i - 1]);
b[i - 1].setBackground(Color.cyan);
b[i - 1].addActionListener(btListener);
}
}

class ButtonListener implements ActionListener {

public void actionPerformed(ActionEvent e) { //handle the button pressing events
int index = Integer.parseInt(e.getActionCommand().substring(1)) - 1;
bp[index] = true;
b[index].setBackground(Color.red);

}
}
} //the end of ButtonPanel class

// The elevator class draws the elevator area and simulates elevator movement
class Elevator extends JPanel implements ActionListener {
//Declaration of variables

private Elevator_Simulation app; //the Elevator Simulation frame
private boolean up; // the elevator is moving up or down
private int width; // Elevator width
private int height; // Elevator height
private int xco; // The x coordinate of the elevator's upper left corner
private int yco; // The y coordinate of the elevator's upper left corner
private int dy0; // Moving interval
private int topy; //the y coordinate of the top level
private int bottomy; // the y coordinate of the bottom level
private Timer timer; //the timer to drive the elevator movement
private int speed;
private int count;
private boolean stop;
private int level;

public Elevator(Elevator_Simulation app) {
//necessary initialization
this.app = app;
app.state.setText("The elevator is moving up.");

width = app.control.getWidth();
height = app.control.getHeight() / 8;

xco = 160;
yco = 460;

topy = 0;
bottomy = app.control.getHeight();

up = true;
speed = 10;
count = 0;
stop = false;

timer = new Timer(200, this);
timer.start();

}

//Handle the timer events
public void actionPerformed(ActionEvent e) {

speed = app.cSpeed;

if (stop == false) {
if (up == true) { //when th elevator is moving up
app.state.setText("The elevator is moving up.");
yco -= speed;

for (int i = 0; i < 8; i++) {
if ((i * height + topy - yco) < speed && (i * height + topy - yco) > -speed) {
if (app.control.bp[7 - i] == true) {
yco = i * height + topy;
count = 0;
stop = true;
level = 7 - i + 1;
}
}
}

if (yco <= topy) {
yco = topy;
up = false;
app.state.setText("The elevator is moving down.");
}
repaint();
} else { //when th elevator is moving down
app.state.setText("The elevator is moving down.");
yco += speed;

for (int i = 0; i < 8; i++) {
if ((i * height + topy - yco) < speed && (i * height + topy - yco) > -speed) {
if (app.control.bp[7 - i] == true) {
yco = i * height + topy;
count = 0;
stop = true;
level = 7 - i + 1;
}
}
}

if (yco + height >= bottomy) {
yco = bottomy - height;
up = true;
app.state.setText("The elevator is moving up.");
}

repaint();
}
} else { //when th elevator is stopped

if (count == 0) {
repaint();
app.state.setText("The elevator is picking up passengers at floor " + level);
}

count++;
int countN = 6;
if (speed > 10) {
countN -= (speed - 10) / 2;
}
if (speed < 10) {
countN += (10 - speed) / 3;
}
if (count > countN) {
app.control.b[level - 1].setBackground(Color.cyan);
app.control.bp[level - 1] = false;

stop = false;

if (up == true) {
app.state.setText("The elevator is moving up.");
}
if (up == false) {
app.state.setText("The elevator is moving down.");
}
}

}
}

// Paint elevator area
public void paintComponent(Graphics g) {
xco = this.getWidth() / 2 - width / 2;

width = app.control.getWidth();
height = app.control.getHeight() / 8;

topy = 0;
bottomy = height * 8;
//obtain geometric values of components for drawing the elevator area

super.paintComponent(g);
//clear the painting canvas

this.setBackground(Color.yellow);
for (int i = 0; i <= 8; i++) {
g.drawLine(0, height * i, this.getWidth(), height * i);
}

g.setColor(Color.black);
g.fillRect(xco, yco, width, height);
if (!stop) {
g.setColor(Color.lightGray);
g.fillRect(xco, yco, width / 2, height);
g.fillRect(xco + width / 2, yco, width / 2 + 1, height);
}
g.setColor(Color.black);
g.drawLine(xco + width / 2, yco, xco + width / 2, yco + height);
//draw horizontal lines and the elevator 
}
} //the end of Elevator class