从一个ArrayList重新粉刷一类的一个实例 [英] Repainting an instance of a class from an ArrayList
问题描述
好了，所以我很新的Java Swing和Java中，一般初学者。我现在的问题是，我已经设计了一个城市景观。我在一个不明飞行物工作到处飞，但我的随机生成的建筑继续得到再生。 我想知道是否有一种方法，以我的建筑实例保存到一个ArrayList，因为我曾尝试和油漆从该列表中的每一次油漆被称为该选择。我想我的想法和我的相信这只是它坠毁时运行，因为它甚至没有打开一个JFrame，而是产生于错误的错误。以下是我有：
Ok so I am very new to Java Swing and a beginner in Java in general. My current problem is I have designed a "cityscape". I am working on a UFO flying around, but my randomly generated buildings continue to get regenerated. I am wondering if there is a way to save my instance of buildings to an ArrayList as I have attempted, and paint that selection from that list each time paint is called. I tried what I thought of and I believe it just crashed it when run, because it didn't even open a JFrame and instead produced errors upon errors. Here is what I have:
市容类（主类）：
import java.awt.*;
import javax.swing.*;
public class CityScape extends JPanel
{
Buildings a = new Buildings ();
UFO b = new UFO();
@Override
public void paint (Graphics g)
{
//RememberBuildings.buildingList.get(1).paint(g);
a.paint(g);
b.paint(g);
}
public void move()
{
b.move();
}
public static void main(String[] args) throws InterruptedException
{
JFrame frame = new JFrame("Frame");
CityScape jpe = new CityScape();
frame.add(jpe);
frame.setSize(800, 750);
frame.setBackground(Color.BLACK);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
System.out.println(frame.getContentPane().getSize());
while (true)
{
jpe.move(); //Updates the coordinates
jpe.repaint(); //Calls the paint method
Thread.sleep(10); //Pauses for a moment
}
}
}
建筑类（即产生建筑类）：
Buildings class (the class that generates the buildings):
import java.awt.*;
public class Buildings
{
private int maxX = 784;
private int maxY = 712;
private int width = (int)(Math.random()*100+100);
private int height = (int)(Math.random()*350+100);
private int rows = Math.round((height)/25);
private int columns = Math.round(width/25);
public void addBuilding()
{
RememberBuildings.addBuilding();
}
public void paint(Graphics g)
{
Graphics2D g2d = (Graphics2D) g;
Color transYellow = new Color (255, 255, 0, 59);
g2d.setColor(Color.BLACK);
g2d.fillRect(0, 0, maxX, maxY);
g2d.setColor(Color.WHITE);
g2d.fillRect(5, 5, 25, 25);
int a = 0;
for (int i =10; i<634; i+=(a+10))//buildings
{
g2d.setColor(Color.GRAY);
g2d.drawRect(i, maxY-height, width, height);
g2d.fillRect(i, maxY-height, width, height);
rows = Math.round((height)/25);
columns = Math.round(width/25);
for (int j = 1; j<=columns; j++)//windows
{
for (int k = 1; k<=rows; k++)
{
g2d.setColor(Color.BLACK);
g2d.drawRect(i+5*j+20*(j-1), (maxY-height)+5*k+20*(k-1), 20, 20);
if (Math.random()<0.7)
{
g2d.setColor(Color.YELLOW);
g2d.fillRect(i+5*j+20*(j-1), (maxY-height)+5*k+20*(k-1), 20, 20);
}
else
{
g2d.setColor(Color.BLACK);
g2d.fillRect(i+5*j+20*(j-1), (maxY-height)+5*k+20*(k-1), 20, 20);
g2d.setColor(transYellow);
g2d.fillRect(i+5*j+20*(j-1), (maxY-height)+5*k+20*(k-1), 20, 20);
}
}
}
addBuilding();
a = width;
height = (int)(Math.random()*462+100);
width = (int)(Math.random()*100+100);
}
}
}
RememberBuildings类（这点是一个实例添加到一个ArrayList）：
RememberBuildings class (the point of this is to add an instance to an ArrayList):
import java.util.*;
public class RememberBuildings
{
public static ArrayList<Buildings> buildingList = new ArrayList<Buildings>();
public static void addBuilding()
{
buildingList.add(new Buildings());
}
}
最后我UFO类（将产生不明飞行物飞过）：
And finally my UFO class (creates the UFO flying by):
import java.awt.*;
import javax.swing.*;
public class UFO extends JPanel
{
private int x = 20; //x and y coordinates of the ball
private int y = 20;
private int xa = 1;
public void move() //Increase both the x and y coordinates
{
if (x + xa < 0) {
xa = 1;
}
if (x + xa > 784-75)
{
xa = -1;
}
x = x + xa;
}
public void paint(Graphics g)
{
super.paint(g); //Clears the panel, for a fresh start
Graphics2D g2d = (Graphics2D) g;
g2d.setColor(Color.LIGHT_GRAY);
g2d.fillOval(x,y,75,25); //Draw the ball at the desired point
}
}
推荐答案
所以，每次建筑＃油漆被调用，它再生所有的版本，这是随机的
So, every time Buildings#paint is called, it regenerates all the builds, which is done randomly.
public void paint(Graphics g) {
Graphics2D g2d = (Graphics2D) g;
Color transYellow = new Color(255, 255, 0, 59);
g2d.setColor(Color.BLACK);
g2d.fillRect(0, 0, maxX, maxY);
g2d.setColor(Color.WHITE);
g2d.fillRect(5, 5, 25, 25);
int a = 0;
for (int i = 10; i < 634; i += (a + 10))//buildings
{
g2d.setColor(Color.GRAY);
g2d.drawRect(i, maxY - height, width, height);
g2d.fillRect(i, maxY - height, width, height);
rows = Math.round((height) / 25);
columns = Math.round(width / 25);
for (int j = 1; j <= columns; j++)//windows
{
for (int k = 1; k <= rows; k++) {
g2d.setColor(Color.BLACK);
g2d.drawRect(i + 5 * j + 20 * (j - 1), (maxY - height) + 5 * k + 20 * (k - 1), 20, 20);
if (Math.random() < 0.7) {
g2d.setColor(Color.YELLOW);
g2d.fillRect(i + 5 * j + 20 * (j - 1), (maxY - height) + 5 * k + 20 * (k - 1), 20, 20);
} else {
g2d.setColor(Color.BLACK);
g2d.fillRect(i + 5 * j + 20 * (j - 1), (maxY - height) + 5 * k + 20 * (k - 1), 20, 20);
g2d.setColor(transYellow);
g2d.fillRect(i + 5 * j + 20 * (j - 1), (maxY - height) + 5 * k + 20 * (k - 1), 20, 20);
}
}
}
addBuilding();
a = width;
height = (int) (Math.random() * 462 + 100);
width = (int) (Math.random() * 100 + 100);
}
}
有两种方法，你也许能够解决这个问题，您可以用将取决于你想要达到的目标。你可以直接渲染建筑到的BufferedImage 并简单地画上每个油漆周期或者你可以缓存你为了重新创建建筑需要的信息。
There's two ways you might be able to solve this, which you use will depend on what you want to achieve. You could render the buildings directly to a BufferedImage and simply paint that on each paint cycle or you could cache the information you need in order to re-create the buildings.
的的BufferedImage 办法是更快，但不能动画，所以如果你想以某种方式（让灯闪烁），以动画的建筑，您将需要建立了一系列的让您只需重绘它们的信息。
The BufferedImage approach is quicker, but can't be animated, so if you want to animate the buildings in some way (make the lights flicker), you will need to build up a series of information which allows you to simply repaint them.
我要为第二个，因为你已经问了一下绘画资产从的ArrayList 。
I'm going for the second, as you've asked about painting assets from a ArrayList.
我开始通过翻译你的漆code到虚拟建筑的一个单一的概念，这也有一个关于它自己的指示灯的信息。
I started by translating your "paint" code into a single concept of a virtual building, which has also has information about it's own lights.
public class Building {
protected static final Color TRANS_YELLOW = new Color(255, 255, 0, 59);
private int x, y, width, height;
private List<Light> lights;
public Building(int x, int y, int width, int height) {
this.x = x;
this.y = y;
this.width = width;
this.height = height;
lights = new ArrayList<>(25);
int rows = Math.round((height) / 25);
int columns = Math.round(width / 25);
for (int j = 1; j <= columns; j++)//windows
{
for (int k = 1; k <= rows; k++) {
Color color = null;
if (Math.random() < 0.7) {
color = Color.YELLOW;
} else {
color = TRANS_YELLOW;
}
lights.add(new Light(x + 5 * j + 20 * (j - 1), y + 5 * k + 20 * (k - 1), color));
}
}
}
public void paint(Graphics2D g2d) {
g2d.setColor(Color.GRAY);
g2d.drawRect(x, y, width, height);
g2d.fillRect(x, y, width, height);
for (Light light : lights) {
light.paint(g2d);
}
}
public class Light {
private int x, y;
private Color color;
public Light(int x, int y, Color color) {
this.x = x;
this.y = y;
this.color = color;
}
public void paint(Graphics2D g2d) {
g2d.setColor(Color.BLACK);
g2d.fillRect(x, y, 20, 20);
g2d.setColor(color);
g2d.fillRect(x, y, 20, 20);
}
}
}
这让你产生了建筑和简单的缓存结果，并在需要时，只需画它。
This allows you to generate the primary parameters for the Building and simple cache the results and when needed, simply paint it.
例如...
public class Buildings {
private int maxX = 784;
private int maxY = 712;
private List<Building> buildings;
public Buildings() {
buildings = new ArrayList<>(25);
for (int i = 10; i < 634; i += 10)//buildings
{
int width = (int) (Math.random() * 100 + 100);
int height = (int) (Math.random() * 350 + 100);
int x = i;
int y = maxY - height;
buildings.add(new Building(x, y, width, height));
}
}
public void paint(Graphics g) {
Graphics2D g2d = (Graphics2D) g;
for (Building building : buildings) {
building.paint(g2d);
}
}
}
我也改变了你的 UFO 类，使之不再从的JPanel 延伸，因为它只是不需要并可能是混乱的主要原因与你的画。
I also changed your UFO class so it no longer extends from JPanel, as it just doesn't need to and is probably the primary cause of confusion with your painting.
然后我更新了油漆方法在市容使用的paintComponent ，而不是...
I then updated your paint method in your CityScape to use paintComponent instead...
public class CityScape extends JPanel {
Buildings a = new Buildings();
UFO b = new UFO();
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
a.paint(g);
b.paint(g);
}
作为一个可运行的例子...
As a runnable example...
![城市景观](\"http://i.stack.imgur.com/sFZmA.gif\")
import java.awt.Color;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.List;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class CityScape extends JPanel {
Buildings a = new Buildings();
UFO b = new UFO();
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g); //To change body of generated methods, choose Tools | Templates.
a.paint(g);
b.paint(g);
}
public void move() {
b.move();
}
public static void main(String[] args) throws InterruptedException {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
JFrame frame = new JFrame("Frame");
CityScape jpe = new CityScape();
frame.add(jpe);
frame.setSize(800, 750);
frame.setBackground(Color.BLACK);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
System.out.println(frame.getContentPane().getSize());
Timer timer = new Timer(10, new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
jpe.move(); //Updates the coordinates
jpe.repaint(); //Calls the paint method
}
});
timer.start();
}
});
}
public class Buildings {
private int maxX = 784;
private int maxY = 712;
private List<Building> buildings;
public Buildings() {
buildings = new ArrayList<>(25);
for (int i = 10; i < 634; i += 10)//buildings
{
int width = (int) (Math.random() * 100 + 100);
int height = (int) (Math.random() * 350 + 100);
int x = i;
int y = maxY - height;
buildings.add(new Building(x, y, width, height));
}
}
public void paint(Graphics g) {
Graphics2D g2d = (Graphics2D) g;
for (Building building : buildings) {
building.paint(g2d);
}
}
}
public static class Building {
protected static final Color TRANS_YELLOW = new Color(255, 255, 0, 59);
private int x, y, width, height;
private List<Light> lights;
public Building(int x, int y, int width, int height) {
this.x = x;
this.y = y;
this.width = width;
this.height = height;
lights = new ArrayList<>(25);
int rows = Math.round((height) / 25);
int columns = Math.round(width / 25);
for (int j = 1; j <= columns; j++)//windows
{
for (int k = 1; k <= rows; k++) {
Color color = null;
if (Math.random() < 0.7) {
color = Color.YELLOW;
} else {
color = TRANS_YELLOW;
}
lights.add(new Light(x + 5 * j + 20 * (j - 1), y + 5 * k + 20 * (k - 1), color));
}
}
}
public void paint(Graphics2D g2d) {
g2d.setColor(Color.GRAY);
g2d.drawRect(x, y, width, height);
g2d.fillRect(x, y, width, height);
for (Light light : lights) {
light.paint(g2d);
}
}
public class Light {
private int x, y;
private Color color;
public Light(int x, int y, Color color) {
this.x = x;
this.y = y;
this.color = color;
}
public void paint(Graphics2D g2d) {
g2d.setColor(Color.BLACK);
g2d.fillRect(x, y, 20, 20);
g2d.setColor(color);
g2d.fillRect(x, y, 20, 20);
}
}
}
public class UFO {
private int x = 20; //x and y coordinates of the ball
private int y = 20;
private int xa = 1;
public void move() //Increase both the x and y coordinates
{
if (x + xa < 0) {
xa = 1;
}
if (x + xa > 784 - 75) {
xa = -1;
}
x = x + xa;
}
public void paint(Graphics g) {
Graphics2D g2d = (Graphics2D) g;
g2d.setColor(Color.LIGHT_GRAY);
g2d.fillOval(x, y, 75, 25); //Draw the ball at the desired point
}
}
}
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