Java 图形对象不会随着xPosition的更新而更新
我试图创建一个行星(蓝色圆圈),并在更新x位置时使其移动。这是主要课程Java 图形对象不会随着xPosition的更新而更新,java,render,increment,Java,Render,Increment,我试图创建一个行星(蓝色圆圈),并在更新x位置时使其移动。这是主要课程 import java.awt.Canvas; import java.awt.Color; import java.awt.Dimension; import java.awt.Graphics; import java.awt.Graphics2D; import javax.swing.JFrame; public class Main extends Canvas implements Runnable{
import java.awt.Canvas;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import javax.swing.JFrame;
public class Main extends Canvas implements Runnable{
public int width = 1400;
public int height = (width/16)* 9;
Dimension dim = new Dimension(width, height);
JFrame frame;
boolean running;
NewBody earth;
public Main(){
this.setPreferredSize(dim);
this.setBackground(Color.BLACK);
}
public void start(){
running = true;
Thread thread = new Thread(this, "display");
thread.start();
}
public void run(){
long startTime = System.currentTimeMillis();
double conv = Math.pow(10, 3);
while(running){
long now = System.currentTimeMillis();
if((now-startTime)/conv >= 1){
earth.incXPos();
startTime = now;
return;
}
update();
}
}
public void update(){
repaint();
}
public void stop(){
running = false;
}
public void paint(Graphics g){
Graphics2D g2d = (Graphics2D)g;
g2d.setColor(Color.BLUE);
g2d.fillOval(earth.xPos,earth.yPos, earth.radius*2, earth.radius*2);
}
public static void main(String args[]){
Main main = new Main();
main.frame = new JFrame();
main.frame.setResizable(false);
main.frame.add(main);
main.frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
main.frame.pack();
main.frame.setVisible(true);
main.earth = new NewBody(0, 0,0, 50);
main.start();
}
}
这是我创造“地球”的新人蓝图
问题是,当我运行程序时,蓝色圆圈只是停留在相同的位置,在那里它被初始化。它只是闪烁的非常快,没有别的事情发生。我对编码很陌生,我似乎没有收到任何错误信息,因此我不知道如何继续。我已经在这个问题上纠缠了好几个小时了
你有什么想法吗 返回
run()
方法中的code>语句导致该方法短路退出,因此在调用incXPos()
一次后立即退出。这甚至发生在调用update()
之前,因此永远不会调用repaint()
不过,我会做一些不同的事情:
- 我会画一张JPanel
- 我会使用它的paintComponent方法
- 我会使用Swing计时器而不是线程来执行动画循环
- 我一定要在我的覆盖内调用super的
paintComponent(g)
例如:
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
public class SimpleAnimation extends JPanel {
private static final int PREF_W = 1400;
private static final int PREF_H = (PREF_W * 9) / 16; // do int mult **first**
private static final int TIMER_DELAY = 13;
private NewBody earth = new NewBody(0, 0, 0, 50);
public SimpleAnimation() {
new Timer(TIMER_DELAY, new TimerListener()).start();
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g;
// to allow for smooth graphics
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
g2d.setColor(Color.BLUE);
g2d.fillOval(earth.xPos, earth.yPos, earth.radius * 2, earth.radius * 2);
}
@Override
public Dimension getPreferredSize() {
if (isPreferredSizeSet()) {
return super.getPreferredSize();
}
return new Dimension(PREF_W, PREF_H);
}
private class TimerListener implements ActionListener {
@Override
public void actionPerformed(ActionEvent e) {
earth.incXPos();
repaint();
}
}
private static void createAndShowGui() {
SimpleAnimation mainPanel = new SimpleAnimation();
JFrame frame = new JFrame("SimpleAnimation");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
class NewBody {
// !! Main main = new Main();
public int xOrigo = 1400 / 2;
public int yOrigo = 800 / 2;
public double mass;
public double velocity;
public int xPos;
public int yPos;
public double force;
public double vectorAngle;
public double fx;
public double fy;
public double acceleration;
public int radius;
public NewBody(double mass, int xPos, int yPos, int radius) {
this.mass = mass;
this.xPos = xOrigo + xPos - radius;
this.yPos = yOrigo + yPos - radius;
this.radius = radius;
}
public void incXPos() {
this.xPos++;
}
}
返回run()
方法中的code>语句导致该方法短路退出,因此在调用incXPos()
一次后立即退出。这甚至发生在调用update()
之前,因此永远不会调用repaint()
不过,我会做一些不同的事情:
- 我会画一张JPanel
- 我会使用它的paintComponent方法
- 我会使用Swing计时器而不是线程来执行动画循环
- 我一定要在我的覆盖内调用super的
paintComponent(g)
例如:
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
public class SimpleAnimation extends JPanel {
private static final int PREF_W = 1400;
private static final int PREF_H = (PREF_W * 9) / 16; // do int mult **first**
private static final int TIMER_DELAY = 13;
private NewBody earth = new NewBody(0, 0, 0, 50);
public SimpleAnimation() {
new Timer(TIMER_DELAY, new TimerListener()).start();
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g;
// to allow for smooth graphics
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
g2d.setColor(Color.BLUE);
g2d.fillOval(earth.xPos, earth.yPos, earth.radius * 2, earth.radius * 2);
}
@Override
public Dimension getPreferredSize() {
if (isPreferredSizeSet()) {
return super.getPreferredSize();
}
return new Dimension(PREF_W, PREF_H);
}
private class TimerListener implements ActionListener {
@Override
public void actionPerformed(ActionEvent e) {
earth.incXPos();
repaint();
}
}
private static void createAndShowGui() {
SimpleAnimation mainPanel = new SimpleAnimation();
JFrame frame = new JFrame("SimpleAnimation");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
class NewBody {
// !! Main main = new Main();
public int xOrigo = 1400 / 2;
public int yOrigo = 800 / 2;
public double mass;
public double velocity;
public int xPos;
public int yPos;
public double force;
public double vectorAngle;
public double fx;
public double fy;
public double acceleration;
public int radius;
public NewBody(double mass, int xPos, int yPos, int radius) {
this.mass = mass;
this.xPos = xOrigo + xPos - radius;
this.yPos = yOrigo + yPos - radius;
this.radius = radius;
}
public void incXPos() {
this.xPos++;
}
}
返回run()
方法中的code>语句导致该方法短路退出,因此在调用incXPos()
一次后立即退出。这甚至发生在调用update()
之前,因此永远不会调用repaint()
不过,我会做一些不同的事情:
- 我会画一张JPanel
- 我会使用它的paintComponent方法
- 我会使用Swing计时器而不是线程来执行动画循环
- 我一定要在我的覆盖内调用super的
paintComponent(g)
例如:
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
public class SimpleAnimation extends JPanel {
private static final int PREF_W = 1400;
private static final int PREF_H = (PREF_W * 9) / 16; // do int mult **first**
private static final int TIMER_DELAY = 13;
private NewBody earth = new NewBody(0, 0, 0, 50);
public SimpleAnimation() {
new Timer(TIMER_DELAY, new TimerListener()).start();
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g;
// to allow for smooth graphics
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
g2d.setColor(Color.BLUE);
g2d.fillOval(earth.xPos, earth.yPos, earth.radius * 2, earth.radius * 2);
}
@Override
public Dimension getPreferredSize() {
if (isPreferredSizeSet()) {
return super.getPreferredSize();
}
return new Dimension(PREF_W, PREF_H);
}
private class TimerListener implements ActionListener {
@Override
public void actionPerformed(ActionEvent e) {
earth.incXPos();
repaint();
}
}
private static void createAndShowGui() {
SimpleAnimation mainPanel = new SimpleAnimation();
JFrame frame = new JFrame("SimpleAnimation");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
class NewBody {
// !! Main main = new Main();
public int xOrigo = 1400 / 2;
public int yOrigo = 800 / 2;
public double mass;
public double velocity;
public int xPos;
public int yPos;
public double force;
public double vectorAngle;
public double fx;
public double fy;
public double acceleration;
public int radius;
public NewBody(double mass, int xPos, int yPos, int radius) {
this.mass = mass;
this.xPos = xOrigo + xPos - radius;
this.yPos = yOrigo + yPos - radius;
this.radius = radius;
}
public void incXPos() {
this.xPos++;
}
}
返回run()
方法中的code>语句导致该方法短路退出,因此在调用incXPos()
一次后立即退出。这甚至发生在调用update()
之前,因此永远不会调用repaint()
不过,我会做一些不同的事情:
- 我会画一张JPanel
- 我会使用它的paintComponent方法
- 我会使用Swing计时器而不是线程来执行动画循环
- 我一定要在我的覆盖内调用super的
paintComponent(g)
例如:
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
public class SimpleAnimation extends JPanel {
private static final int PREF_W = 1400;
private static final int PREF_H = (PREF_W * 9) / 16; // do int mult **first**
private static final int TIMER_DELAY = 13;
private NewBody earth = new NewBody(0, 0, 0, 50);
public SimpleAnimation() {
new Timer(TIMER_DELAY, new TimerListener()).start();
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g;
// to allow for smooth graphics
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
g2d.setColor(Color.BLUE);
g2d.fillOval(earth.xPos, earth.yPos, earth.radius * 2, earth.radius * 2);
}
@Override
public Dimension getPreferredSize() {
if (isPreferredSizeSet()) {
return super.getPreferredSize();
}
return new Dimension(PREF_W, PREF_H);
}
private class TimerListener implements ActionListener {
@Override
public void actionPerformed(ActionEvent e) {
earth.incXPos();
repaint();
}
}
private static void createAndShowGui() {
SimpleAnimation mainPanel = new SimpleAnimation();
JFrame frame = new JFrame("SimpleAnimation");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
class NewBody {
// !! Main main = new Main();
public int xOrigo = 1400 / 2;
public int yOrigo = 800 / 2;
public double mass;
public double velocity;
public int xPos;
public int yPos;
public double force;
public double vectorAngle;
public double fx;
public double fy;
public double acceleration;
public int radius;
public NewBody(double mass, int xPos, int yPos, int radius) {
this.mass = mass;
this.xPos = xOrigo + xPos - radius;
this.yPos = yOrigo + yPos - radius;
this.radius = radius;
}
public void incXPos() {
this.xPos++;
}
}
谢谢你的意见。为什么会短路?是因为while循环中的“return”语句吗?好吧,那么你是建议我把画布一起移走?为什么JPanel比Canvas好?我会查看swing timer,谢谢!:)@Arcthor:它会短路,因为return会立即从方法中退出。只循环一次的while循环不是一个非常有用的构造。默认情况下,使用JPanel的paintComponent方法可以提供双缓冲图形。非常感谢。真的很有帮助。如果你不介意的话,我还有一个问题。为什么我不应该在NewBody中创建一个主构造函数?如果我不能做到这一点,我如何访问widt和height等变量?@arctor:如果你在NewBody中创建一个新的主对象,它将是一个全新的、独特的对象,一个与原始主对象完全不同的对象,这不会太有帮助。如果您需要NewBody中的主实例,您将希望传入引用,可能是在构造函数中。感谢您的输入。为什么会短路?是因为while循环中的“return”语句吗?好吧,那么你是建议我把画布一起移走?为什么JPanel比Canvas好?我会查看swing timer,谢谢!:)@Arcthor:它会短路,因为return会立即从方法中退出。只循环一次的while循环不是一个非常有用的构造。默认情况下,使用JPanel的paintComponent方法可以提供双缓冲图形。非常感谢。真的很有帮助。如果你不介意的话,我还有一个问题。为什么我不应该在NewBody中创建一个主构造函数?如果我不能做到这一点,我如何访问widt和height等变量?@arctor:如果你在NewBody中创建一个新的主对象,它将是一个全新的、独特的对象,一个与原始主对象完全不同的对象,这不会太有帮助。如果您需要NewBody中的主实例,您将希望传入引用,可能是在构造函数中。感谢您的输入。为什么会短路?是因为while循环中的“return”语句吗?好吧,那么你是建议我把画布一起移走?为什么JPanel比Canvas好?我会查看swing timer,谢谢!:)@Arcthor:它会短路,因为return会立即从方法中退出。只循环一次的while循环不是一个非常有用的构造。默认情况下,使用JPanel的paintComponent方法可以提供双缓冲图形。非常感谢。真的很有帮助。如果你不介意的话,我还有一个问题。为什么我不应该在NewBody中创建一个主构造函数?如果我不能做到这一点,我如何访问widt和height等变量?@arctor:如果你在NewBody中创建一个新的主对象,它将是一个全新的、独特的对象,一个与原始主对象完全不同的对象