主类中的摆动计时器不会重新绘制 JFrame 类

Question

我有一个主类，它保存了一个对象的数组列表，并有一个 Swing 计时器，可以重新绘制一个单独的 JFrame 类。尽管调用了重绘方法，但屏幕并未更新。

应该发生什么：当按下任何键时，两个对象的 x 位置将更新。每半秒滴答一次的摆动计时器调用重绘方法。然后在更新的位置重绘图像。

据我所知，图像的位置正在更新，因为当我最小化并重新打开 JFrame 窗口时，图像已经移动。

我尝试更改计时器运行的间隔，将摆动计时器移动到 JFrame 类，将 repaint((; 放在线程中。但是我仍然不知道为什么要重绘((;未更新屏幕。

这是我的代码草图：JFrame 类

public class testingGround extends JPanel {
    private Image image;
    private qwq getter = new qwq();
    protected Keyboard keyboard = new Keyboard(); //KeyListener, imported from Keyboard class
    private JFrame frame = new JFrame(); //JFrame variable
public void createGUI(){
    testingGround panel = new testingGround(); // Creating a new JPanel, for objects to be drawn on
    JFrame frame = new JFrame("Game"); //Creating a new JFrame called frame 
    frame.setSize(600, 600); //Setting the size of the JFrame frame to be 600x600
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);// Setting so the frame exits on close
    frame.setVisible(true);
    frame.add(panel);// Adding the JPanel panel to the JFrame frame, so it's visible 
    frame.addKeyListener(keyboard); //Adding a KeyListener to detect users input in the JFrame frame
}   
public Frame getFrame() { //Constructor class to get JFrame in other classes
    return frame;
}
public void initComponents(){
    ImageIcon imageIcon = new ImageIcon("C:/Users/destr/workspace/GameWIP3/bin/A2.png");
    image =imageIcon.getImage();
}
protected void paintComponent (Graphics g){//Drawing
    super.paintComponent(g);
    initComponents();
    for (int i=0;i<getter.getFListSize();i++)
    {
    System.out.print("paint called");   
    g.drawImage(image, getter.getFighter(i).getFighterX(), getter.getFighter(i).getFighterY(), null);
    }
}
}

键盘类

public class Keyboard implements KeyListener {
private qwq getter = new qwq();
@Override
public void keyPressed(KeyEvent e) {
    getter.getFighter(0).setFighterX(500);;
    getter.getFighter(1).setFighterX(200);; 
    System.out.print("Updated the x value of two");
}

主类

public class qwq implements ActionListener {
private static ArrayList<Fighter> FighterList = new ArrayList<Fighter>(); // ArrayList                                                                          // of                                                               // Fighters
Timer timer = new Timer(500, this);
private static testingGround GUI = new testingGround();
public qwq() {
    timer.start();
}
public Fighter getFighter(int i) {
    return FighterList.get(i); // To retrieve a fighter from the Array List
}
public void addFighter(Fighter i) {
    FighterList.add(i); // To add a fighter to the Array list
}
public int getFListSize() {
    return FighterList.size();
}
public static void main(String[] args) {
    GUI.createGUI();
    GUI.getFrame();
    FighterList.add(new Fighter(0, 0));
    FighterList.add(new Fighter(20, 50));
}
@Override
public void actionPerformed(ActionEvent e) {
    if (e.getSource() == timer) {
        GUI.repaint();
    }
}
}

对象类

public class Fighter { 
    private int fighterX;
    private int fighterY;
public Fighter ( int fighterX, int fighterY) {
this.setFighterX(fighterX);
this.setFighterY (fighterY);
}
public int getFighterX (){
return fighterX; //method to get x coordinate of a fighter
}
public int getFighterY (){
return fighterY;//method to get y coordinate of a fighter
}
public void setFighterX(int fighterX) {
this.fighterX = fighterX; //method to set the x coordinate of a fighter
}
public void setFighterY(int fighterY) {
this.fighterY = fighterY; //method to set the y coordinate of a fighter
}
}

Answer 1

• 您正在创建qwq的多个实例，testingGround和Keyboard，这些实例彼此无关，仅意味着您现在每次创建它的新实例时都会创建一个新Timer
• 在你的testingGround#createGUI你创建了一个新的testingGround实例，它被添加到JFrame的新实例中，所以qwq必须testingGround的引用与实际在屏幕上的实例无关！？ 此外，您在createGUI中创建一个新的JFrame实例，该实例与您从getFrame返回的JFrame实例无关！？

OO是关于责任的，谁负责什么。 例如，你testingGround类不应该制作框架，这不是它的责任。 它应该负责渲染游戏的当前状态。

例如。。。

import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class Qwq {
    public static void main(String[] args) {
        new Qwq();
    }
    public Qwq() {
        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("Testing");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.add(new TestingGround());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }
    public class Keyboard extends KeyAdapter {
        private List<Fighter> fighterList;
        public Keyboard(List<Fighter> fighterList) {
            this.fighterList = fighterList;
        }
        @Override
        public void keyPressed(KeyEvent e) {
            fighterList.get(0).setFighterX(500);
            fighterList.get(1).setFighterX(200);
            System.out.print("Updated the x value of two");
        }
    }
    public class TestingGround extends JPanel {
        private ArrayList<Fighter> fighterList = new ArrayList<>(); 
        private Image image;
        private Keyboard keyboard;
        public TestingGround() {
            loadImages();
            addKeyListener(new Keyboard(Collections.unmodifiableList(fighterList)));
            Timer timer = new Timer(500, new ActionListener() {
                @Override
                public void actionPerformed(ActionEvent e) {
                    repaint();
                }
            });
            timer.start();
        }
        public void loadImages() {
            ImageIcon imageIcon = new ImageIcon("C:/Users/destr/workspace/GameWIP3/bin/A2.png");
            image = imageIcon.getImage();
        }
        protected void paintComponent(Graphics g) {//Drawing
            super.paintComponent(g);
            for (Fighter fighter : fighterList) {
                System.out.print("testing");
                g.drawImage(image, fighter.getFighterX(), fighter.getFighterY(), null);
            }
        }
    }
    public static class Fighter {
        private int fighterX;
        private int fighterY;
        public Fighter(int fighterX, int fighterY) {
            this.setFighterX(fighterX);
            this.setFighterY(fighterY);
        }
        public int getFighterX() {
            return fighterX; //method to get x coordinate of a fighter
        }
        public int getFighterY() {
            return fighterY;//method to get y coordinate of a fighter
        }
        public void setFighterX(int fighterX) {
            this.fighterX = fighterX; //method to set the x coordinate of a fighter
        }
        public void setFighterY(int fighterY) {
            this.fighterY = fighterY; //method to set the y coordinate of a fighter
        }
    }
}

现在，很容易将Timer分开，但我懒惰