我刚开始学习Java。我写了一个这样的程序：
Bacteria.class
import java.awt.*;
public class Bacteria extends Creature{
public static final int COLOR_STEP = 256/MAX_AGE;
Bacteria(Board board, int _x, int _y){
super.board = board;
//initialize age, x, y
super.age = 1;
super.x = _x;
super.y = _y;
}
//Draw a circle representing the creature at its position
//This function is done.
public void draw(Graphics g) {
g.setColor(new Color(0, COLOR_STEP * age, 0));
g.fillOval(x * board.CELL_SIZE, y * board.CELL_SIZE, board.CELL_SIZE, board.CELL_SIZE);
}
public void tick() {
//your code
// this is how the creature lives in one tick
// make the creature get older if it is not dead.
// if it's got older than MAX_AGE then it should die
// ...call board.addDead() to register the dead creature
// if it can have baby then try reproduce()
age++;
if (this.canHaveBaby()) {
this.reproduce();
}
//this.reproduce();
if (age > MAX_AGE) {
board.addDead(this);
}
}
}
Creature.class
import java.awt.*;
public class Creature {
public static final int MAX_AGE = 5;
public Board board;
public int age; // age of the creature measures in ticks
public int x; // (x,y) is the position of the creature
public int y;
Creature(Board board, int _x, int _y) {
this.board = board;
//initialize age, x, y
age = 1;
x = _x;
y = _y;
}
public Creature() {
}
//Draw a circle representing the creature at its position
//This function is done.
public void draw(Graphics g){}
public void tick(){}
public void reproduce() {
//your code
// if it can have a baby then produce a baby
// ...in an empty cell next to its cell.
// board.emptyCell() should be used
// ....to check whether a cell in the board is empty
// and call board.addBaby() to place the baby to the board
//int x_current = x, y_current = y;
if(board.emptyCell(x, y+1)){
Creature baby = new Creature(board,x, y+1);
//System.out.println("1");
board.addBaby( baby);
}
else if(board.emptyCell(x+1,y)){
Creature baby = new Creature(board,x+1, y);
board.addBaby(baby);
}
else if(board.emptyCell(x+1,y+1)){
Creature baby = new Creature(board,x+1, y+1);
board.addBaby(baby);
}
else if(board.emptyCell(x-1,y)){
Creature baby = new Creature(board,x-1, y);
board.addBaby(baby);
}
else if(board.emptyCell(x,y-1)){
Creature baby = new Creature(board,x, y-1);
board.addBaby(baby);
}
else if(board.emptyCell(x-1,y-1)){
Creature baby = new Creature(board,x-1, y-1);
board.addBaby(baby);
}
else if(board.emptyCell(x-1,y+1)){
Creature baby = new Creature(board,x-1, y+1);
board.addBaby(baby);
}
else if(board.emptyCell(x+1,y-1)){
Creature baby = new Creature(board,x+1, y-1);
board.addBaby(baby);
}
}
public boolean canHaveBaby() {
//your code
// if the creature is dead or it is too young
// then it cannot have a baby
if(age == 0 || age > MAX_AGE){
return false;
}
return true;
}
public boolean atPosition(int _x, int _y) {
//your code
// return true if the creature is at the position (_x,_y)
// you need this function for board.empty to function correctly
if(_x == x && _y == y){
return true;
}
return false;
}
}
Board.class
import javax.swing.*;
import java.awt.*;
import java.util.ArrayList;
public class Board extends JPanel {
public static final int CELL_SIZE = 10;
private final int rows = 10;
private final int cols = 20;
ArrayList<Creature> creatureList;
ArrayList<Creature> babies, dead;
// ArrayList<Bacteria> bacteriaList;
// ArrayList<Bacteria> babies_bac, dead_bac;
Board() {
super();
setBackground(Color.white);
creatureList = new ArrayList<Creature>();
//creatureList.size();
babies = new ArrayList<Creature>();
dead = new ArrayList<Creature>();
setPreferredSize(new Dimension(cols * CELL_SIZE, rows * CELL_SIZE));
creatureList.add(new Bacteria(this, 1, 1));
}
@Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
for (Creature creature: creatureList) {
creature.draw(g);
}
}
public void tick() {
dead = new ArrayList<Creature>();
babies = new ArrayList<Creature>();
for (Creature creature: creatureList) {
creature.tick();
}
creatureList.addAll(babies);
creatureList.removeAll(dead);
}
public void addBaby(Creature baby) {
if (baby != null) babies.add(baby);
}
public void addDead(Creature deadCreature) {
if (deadCreature != null) dead.add(deadCreature);
}
public boolean emptyCell(int x, int y) {
if (x < 0 || y < 0 || x >= cols || y >= rows) return false;
for (Creature creature : creatureList) {
if (creature.atPosition(x, y)) {
return false;
}
}
for (Creature creature : creatureList) {
if (creature.atPosition(x, y)) {
return false;
}
}
return true;
}
public String getPopulation() {
return String.format("%d", creatureList.size());
}
}
和BacteriaSimulator.java
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class BacteriaSimulator extends JFrame {
private Board board;
private JLabel label;
public BacteriaSimulator() {
initUI();
setTitle("Bacteria Simulator");
setSize(350, 200);
setLocationRelativeTo(null);
setDefaultCloseOperation(EXIT_ON_CLOSE);
}
private void initUI() {
JPanel panel = new JPanel();
board = new Board();
panel.add(board);
label = new JLabel(board.getPopulation());
panel.add(label);
JButton button = new JButton("Tick");
button.addActionListener(new ButtonNextListener());
panel.add(button);
add(panel);
pack();
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
BacteriaSimulator ex = new BacteriaSimulator();
ex.setVisible(true);
}
});
}
private class ButtonNextListener implements ActionListener {
@Override
public void actionPerformed(ActionEvent e) {
board.tick();
label.setText(board.getPopulation());
repaint();
}
}
}
我希望Board.class与creatureList一起使用。但是，董事会仍然使用细菌(creatureList.add(new Bacteria(this, 1, 1));)初始化。我遇到了一个问题，即Board.class无法运行我想要的draw（）和tick（）方法。如何绘制对象细菌并做出正确的tick（）方法？你能帮助我吗！谢谢！
答案 0 :(得分：0)
您的draw（）和tick（）函数是Bacteria.java的一部分。它们不能在Board.java中使用，除非您创建一个Bacteria实例，然后使用它调用方法。