如何绘制在Java中以不同速度移动的多个对象？ [英] How do I paint multiple objetcs that move at different speeds in Java?
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问题描述
我正在构建源于我的教科书的源代码，我最近更新了过去的作业，但现在我正在尝试生成一个绘制多个方块并移动这些对象的类独立和不同的速度。他们都需要从墙上反弹。我遵循指示并创建了两个数组，它们将随机的x和y值保持在1到10之间。但是，我与数组发生冲突，并且我相信我没有正确地做到这一点。所以，我会喜欢一些反馈，看看我是否设置正确。
我有一个jpanel拉起和绘图，只要有1平方它在墙壁上反弹的效果很好，但是当我绘制多个墙时，情况会发生变化。不会独立移动，它们也具有相同的速度。有些甚至不时消失。这真的把我抛弃了。我感谢任何帮助！
总之，我试图画出所有以不同方向，以不同速度行进的新广场。根据我们所设想的指示，创建并使用处理x和y值的两个数组。
这是我到目前为止：
public class DotsPanel扩展JPanel
{
private int delay = 15;
private final int SIZE = 7，IMAGE_SIZE = 3; //每个点的半径
私人定时器定时器;
private int x，y，i;
private ArrayList< Point> pointList;
static int [] xarray = new int [1000];
static int [] yarray = new int [1000];
Random rand = new Random（）;
// -------------------------------------------- ---------------------
//构造函数：设置此面板以侦听鼠标事件。
// -------------------------------------------- ---------------------
public DotsPanel（）
{
pointList = new ArrayList< Point>（）;
int [] xarray = new int [1000];
int [] yarray = new int [1000];
timer = new Timer（delay，new ReboundListener（））;
addMouseListener（new DotsListener（））;
addMouseMotionListener（new DotsListener（））;
setBackground（Color.gray）;
setPreferredSize（new Dimension（700，500））;
for（int i = 0; i< xarray.length; i ++）
{
xarray [i] = rand.nextInt（7）;
yarray [i] = rand.nextInt（7）;
}
timer.start（）;
}
// ----------------------------------- ------------------------------
//绘制列表中存储的所有点。
// -------------------------------------------- ---------------------
public void paintComponent（Graphics page）
{
super.paintComponent（page）;
page.setColor（Color.BLUE）; （Point point：pointList）
{
page.fillRect（spot.x-SIZE，spot.y-SIZE，25，25）;
page.drawString（Count：+ pointList.size（），5，15）;
}
}
// ********************** *******************************************
//表示鼠标事件的监听器。
// ******************************************** *********************
private class DotsListener实现MouseListener，MouseMotionListener
{
// ------- -------------------------------------------------- -----
//将当前点添加到点列表中，并且每当按下鼠标按钮时重新绘制
//面板。
// -------------------------------------------- ------------------
public void mousePressed（MouseEvent event）
{
pointList.add（event.getPoint（））;
repaint（）;
}
public void mouseDragged（MouseEvent event）
{
//最初我在这里有两个xarray和yarray，就像在
// mouseClicked
//但是当删除
}
// -----------------------------时它没有改变任何东西---------------------------------
//为未使用的事件方法提供空的定义。
// -------------------------------------------- ------------------
public void mouseClicked（MouseEvent event）
{
xarray [i] = rand.nextInt（7）;
yarray [i] = rand.nextInt（7）;
}
public void mouseReleased（MouseEvent event）{}
public void mouseEntered（MouseEvent event）{}
public void mouseExited（MouseEvent event）{} $ b $ public void mouseMoved（MouseEvent e）{}
}
private class ReboundListener实现ActionListener
{
// ------------------ --------------------------------------------
//更新图像的位置，并在计时器触发动作事件时更新动作的方向
//。
// -------------------------------------------- ------------------
public void actionPerformed（ActionEvent event）
{
for（Point point ：pointList）
{
spot.x + = xarray [i];
spot.y + = yarray [i];
if（spot.x< = 0 || spot.x> = 700）
xarray [i] = xarray [i] * -1;
if（spot.y< = 0 || spot.y> = 500）
yarray [i] = yarray [i] * -1;
repaint（）;
}
}
}
}
解决方案
然而，我在数组中挣扎，我确信我没有正确地做。
我不会使用数组。
相反，让一个 Ball 对象管理自己的状态。然后，您可以为每个 Ball 设置不同的颜色，速度，大小等。然后，当 Timer 触发时，您只需计算新位置并重新绘制 Ball 。
下面是一个让你开始的例子：
import java.awt。*;
import java.awt.event。*;
import java.awt.image。*;
import java.util。*;
import javax.swing。*;
import javax.swing.Timer;
public class BallAnimation4
{
private static void createAndShowUI（）
{
BallPanel panel = new BallPanel（500）;
JFrame frame = new JFrame（BallAnimation4）;
frame.setDefaultCloseOperation（JFrame.EXIT_ON_CLOSE）;
frame.setExtendedState（JFrame.MAXIMIZED_BOTH）;
frame.add（panel）;
frame.pack（）;
frame.setVisible（true）;
panel.startAnimation（）;
public static void main（String [] args）
{
EventQueue.invokeLater（new Runnable（）
{
public void run（）
{
createAndShowUI（）;
}
}）;
static class BallPanel extends JPanel implements ActionListener
{
private ArrayList< Ball> balls = new ArrayList< Ball>（）;
public BallPanel（int ballCount）
{
Dimension screenSize = Toolkit.getDefaultToolkit（）。getScreenSize（）;
setLayout（null）;
setBackground（Color.BLACK）;
Random random = new Random（）;
for（int i = 0; i
Ball ball = new Ball（）;
ball.setRandomColor（true）;
ball.setLocation（random.nextInt（screenSize.width），random.nextInt（screenSize.height））;
ball.setMoveRate（32，32，1，1，true）;
ball.setSize（32，32）;
balls.add（ball）;
}
}
@Override
public void paintComponent（Graphics g）
{
super.paintComponent（g）; （球：球）
{
ball.draw（g）;
public void startAnimation（）
{
Timer timer = new Timer（75，this）;
timer.start（）;
public void actionPerformed（ActionEvent e）
{
move（）;
repaint（）;
private void move（）
{
for（Ball ball：balls）
{
ball.move（this）;
}
}
}
静态类Ball
{
public Color color = Color.BLACK;
public int x = 0;
public int y = 0;
public int width = 1;
public int height = 1;
private int moveX = 1;
private int moveY = 1;
private int directionX = 1;
private int directionY = 1;
private int xScale = moveX;
private int yScale = moveY;
private boolean randomMove = false;
private boolean randomColor = false;
private随机myRand = null;
public Ball（）
{
myRand = new Random（）;
setRandomColor（randomColor）;
}
public void move（JPanel parent）
{
int iRight = parent.getSize（）。width;
int iBottom = parent.getSize（）。height;
x + = 5 +（xScale * directionX）;
y + = 5 +（yScale * directionY）;
if（x <= 0）
{
x = 0;
directionX * =（-1）;
xScale = randomMove？ myRand.nextInt（moveX）：moveX;
if（randomColor）setRandomColor（randomColor）;
}
if（x> = iRight - width）
{
x = iRight - width;
directionX * =（-1）;
xScale = randomMove？ myRand.nextInt（moveX）：moveX;
if（randomColor）setRandomColor（randomColor）;
}
if（y <= 0）
{
y = 0;
directionY * =（-1）;
yScale = randomMove？ myRand.nextInt（moveY）：moveY;
if（randomColor）setRandomColor（randomColor）;
}
if（y> = iBottom - height）
{
y = iBottom - height;
directionY * =（-1）;
yScale = randomMove？ myRand.nextInt（moveY）：moveY;
if（randomColor）setRandomColor（randomColor）;
public void draw（Graphics g）
{
g.setColor（color）;
g.fillOval（x，y，width，height）;
}
public void setColor（Color c）
{
color = c;
public void setLocation（int x，int y）
{
this.x = x;
this.y = y;
}
public void setMoveRate（int xMove，int yMove，int xDir，int yDir，boolean randMove）
{
this.moveX = xMove;
this.moveY = yMove;
directionX = xDir;
directionY = yDir;
randomMove = randMove;
}
public void setRandomColor（boolean randomColor）
{
this.randomColor = randomColor;
switch（myRand.nextInt（3））
{
case 0：color = Color.BLUE;
休息;
案例1：color = Color.GREEN;
休息;
案例2：color = Color.RED;
休息;
默认值：color = Color.BLACK;
休息;
}
}
public void setSize（int width，int height）
{
this.width = width;
this.height = height;
因为你的数组只包含你想绘制的Point，你没有关于每个点应该移动的速度的任何信息。您可以做的最好的做法是创建一个随机数量，每个点在每次更改位置时都应该移动。这会导致不稳定的移动，因为每次移动一个点时，距离都是随机的。
如果你想要更多的恒定速度，那么你需要创建第二个数组来包含每个点每次移动的距离。
每当你想要一个新的属性对你想绘制的对象是唯一的时，这开始变得混乱，创建一个新的数组。这就是为什么创建具有多个属性的自定义对象的方法更易于管理。
I am working on homework for class, and its late because I can't seem to understand the material despite all the research that I am doing. I am a beginner and do not know much in the way of java. Also, this is my first post so please be forgiving when you are reading this.
I am building on source code from my textbook, which I updated recently for past homework, but now I am trying to generate a class that draws multiple squares and moves those objects independently and at different speeds. They will all need to rebound off the walls as well. I followed the instructions and created two arrays that will hold the random x and y values between 1 and 10. However, I struggle with arrays and I am sure that I am not doing it correctly. So, I would love some feedback to see if I have it set up correctly.
I have a the jpanel pulling up and drawing, and as long as there is 1 square it is working fine bouncing off the walls, but things change when I draw more than one. The do not move independently and they also share the same speed. Some even disappear from time to time. This has really thrown me off. I appreciate any help!
In short, I am trying to paint new squares that all travel in different directions and at different speeds. Per the instructions we are suppose create and use a two arrays that handle the x and y values.
Here is what I have so far:
public class DotsPanel extends JPanel
{
private int delay = 15;
private final int SIZE = 7, IMAGE_SIZE = 3; // radius of each dot
private Timer timer;
private int x, y, i;
private ArrayList<Point> pointList;
static int [] xarray = new int [1000];
static int [] yarray = new int [1000];
Random rand = new Random();
//-----------------------------------------------------------------
// Constructor: Sets up this panel to listen for mouse events.
//-----------------------------------------------------------------
public DotsPanel()
{
pointList = new ArrayList<Point>();
int [] xarray = new int [1000];
int [] yarray = new int [1000];
timer = new Timer(delay, new ReboundListener());
addMouseListener (new DotsListener());
addMouseMotionListener (new DotsListener());
setBackground(Color.gray);
setPreferredSize(new Dimension(700, 500));
for(int i = 0; i < xarray.length; i++)
{
xarray[i] = rand.nextInt(7);
yarray[i] = rand.nextInt(7);
}
timer.start();
}
//-----------------------------------------------------------------
// Draws all of the dots stored in the list.
//-----------------------------------------------------------------
public void paintComponent(Graphics page)
{
super.paintComponent(page);
page.setColor(Color.BLUE);
for (Point spot : pointList)
{
page.fillRect(spot.x-SIZE, spot.y-SIZE, 25, 25);
page.drawString("Count: " + pointList.size(), 5, 15);
}
}
//*****************************************************************
// Represents the listener for mouse events.
//*****************************************************************
private class DotsListener implements MouseListener, MouseMotionListener
{
//--------------------------------------------------------------
// Adds the current point to the list of points and redraws
// the panel whenever the mouse button is pressed.
//--------------------------------------------------------------
public void mousePressed(MouseEvent event)
{
pointList.add(event.getPoint());
repaint();
}
public void mouseDragged(MouseEvent event)
{
// initially I had two xarray and yarray in here just like in
// mouseClicked
// but it did not change anything when removed
}
//--------------------------------------------------------------
// Provide empty definitions for unused event methods.
//--------------------------------------------------------------
public void mouseClicked(MouseEvent event)
{
xarray[i] = rand.nextInt(7);
yarray[i] = rand.nextInt(7);
}
public void mouseReleased(MouseEvent event) {}
public void mouseEntered(MouseEvent event) {}
public void mouseExited(MouseEvent event) {}
public void mouseMoved(MouseEvent e) {}
}
private class ReboundListener implements ActionListener
{
//--------------------------------------------------------------
// Updates the position of the image and possibly the direction
// of movement whenever the timer fires an action event.
//--------------------------------------------------------------
public void actionPerformed(ActionEvent event)
{
for (Point spot : pointList)
{
spot.x += xarray[i];
spot.y += yarray[i];
if (spot.x <= 0 || spot.x >= 700)
xarray[i] = xarray[i] * -1;
if (spot.y <= 0 || spot.y >= 500)
yarray[i] = yarray[i] * -1;
repaint();
}
}
}
}
解决方案
However, I struggle with arrays and I am sure that I am not doing it correctly.
I wouldn't use Arrays.
Instead, have a Ball object manage its own state. Then you can have different color, speed, size etc for each Ball. Then when the Timer fires you just calculate the new position and repaint the Ball.
Here is an example to get you started:
import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
import java.util.*;
import javax.swing.*;
import javax.swing.Timer;
public class BallAnimation4
{
private static void createAndShowUI()
{
BallPanel panel = new BallPanel(500);
JFrame frame = new JFrame("BallAnimation4");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setExtendedState(JFrame.MAXIMIZED_BOTH);
frame.add( panel );
frame.pack();
frame.setVisible( true );
panel.startAnimation();
}
public static void main(String[] args)
{
EventQueue.invokeLater(new Runnable()
{
public void run()
{
createAndShowUI();
}
});
}
static class BallPanel extends JPanel implements ActionListener
{
private ArrayList<Ball> balls = new ArrayList<Ball>();
public BallPanel(int ballCount)
{
Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
setLayout( null );
setBackground( Color.BLACK );
Random random = new Random();
for (int i = 0; i < ballCount; i++)
{
Ball ball = new Ball();
ball.setRandomColor(true);
ball.setLocation(random.nextInt(screenSize.width), random.nextInt(screenSize.height));
ball.setMoveRate(32, 32, 1, 1, true);
ball.setSize(32, 32);
balls.add( ball );
}
}
@Override
public void paintComponent(Graphics g)
{
super.paintComponent(g);
for (Ball ball: balls)
{
ball.draw(g);
}
}
public void startAnimation()
{
Timer timer = new Timer(75, this);
timer.start();
}
public void actionPerformed(ActionEvent e)
{
move();
repaint();
}
private void move()
{
for (Ball ball : balls)
{
ball.move(this);
}
}
}
static class Ball
{
public Color color = Color.BLACK;
public int x = 0;
public int y = 0;
public int width = 1;
public int height = 1;
private int moveX = 1;
private int moveY = 1;
private int directionX = 1;
private int directionY = 1;
private int xScale = moveX;
private int yScale = moveY;
private boolean randomMove = false;
private boolean randomColor = false;
private Random myRand = null;
public Ball()
{
myRand = new Random();
setRandomColor(randomColor);
}
public void move(JPanel parent)
{
int iRight = parent.getSize().width;
int iBottom = parent.getSize().height;
x += 5 + (xScale * directionX);
y += 5 + (yScale * directionY);
if (x <= 0)
{
x = 0;
directionX *= (-1);
xScale = randomMove ? myRand.nextInt(moveX) : moveX;
if (randomColor) setRandomColor(randomColor);
}
if (x >= iRight - width)
{
x = iRight - width;
directionX *= (-1);
xScale = randomMove ? myRand.nextInt(moveX) : moveX;
if (randomColor) setRandomColor(randomColor);
}
if (y <= 0)
{
y = 0;
directionY *= (-1);
yScale = randomMove ? myRand.nextInt(moveY) : moveY;
if (randomColor) setRandomColor(randomColor);
}
if (y >= iBottom - height)
{
y = iBottom - height;
directionY *= (-1);
yScale = randomMove ? myRand.nextInt(moveY) : moveY;
if (randomColor) setRandomColor(randomColor);
}
}
public void draw(Graphics g)
{
g.setColor(color);
g.fillOval(x, y, width, height);
}
public void setColor(Color c)
{
color = c;
}
public void setLocation(int x, int y)
{
this.x = x;
this.y = y;
}
public void setMoveRate(int xMove, int yMove, int xDir, int yDir, boolean randMove)
{
this.moveX = xMove;
this.moveY = yMove;
directionX = xDir;
directionY = yDir;
randomMove = randMove;
}
public void setRandomColor(boolean randomColor)
{
this.randomColor = randomColor;
switch (myRand.nextInt(3))
{
case 0: color = Color.BLUE;
break;
case 1: color = Color.GREEN;
break;
case 2: color = Color.RED;
break;
default: color = Color.BLACK;
break;
}
}
public void setSize(int width, int height)
{
this.width = width;
this.height = height;
}
}
}
Since your Arrays only contain the Point you want to paint you don't have any information about the speed each point should be moved at. The best you could do is create a random amount each point should be moved each time its location is changed. This would give erratic movement as each time you move a point the distance would be random.
If you want more constant speed then you would need to create a second Array to contain the distance each point should move every time.
This starts to get messy creating a new Array every time you want a new property to be unique for the object you want to paint. That is why the approach to create a custom Object with multiple properties is easier to manage.
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