java - 为什么我创建的随机矩形没有出现在我的游戏中？

Question

我是 gui java 新手，我一直在尝试重新创建名为“jump it”( http://www.crazygames.com/game/jump-it )的游戏，目前我正在为我的角色制作随机矩形以供其跳跃。但是我运行了我的代码并且没有错误，但是我制作的矩形没有显示。我在下面附上了我的代码，对此我感到很抱歉。

import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
import java.util.Random;
import java.util.TimerTask;

class GuiGame{
 public static void main(String args[]) {
    JFrame f = new JFrame("RUN - Christine & Esther"); //title of frame
    Container cont = f.getContentPane();  // get container - top of the frame
    cont.setLayout(new BorderLayout()); 
    BtnActPanel bp = new BtnActPanel();  // create an object of our game panel
    cont.add(bp, BorderLayout.CENTER );
    f.setVisible(true);
    f.setSize(975,613); //size of frame
 }
}

class Rectangle{
    static Random r = new Random();
    static int upperX = 100;
    static int lowerX = 20;
    static int upperY = 550;
    static int lowerY = 450;
    static int minWidth = 200;
    static int maxWidth = 600;
    static int minHeight = 40;
    static int maxHeight = 140;
    static int  x = 0, y = 0, w = 0, h = 0, check = 0;

    public Rectangle(){
        check++;
        int x = 650 + 50*check;
        int y = r.nextInt(upperY-lowerY + 1) + lowerY; // from 450 to 550
        int w = r.nextInt(maxWidth-minWidth + 1) + minWidth; // from 200 to 600
        int h = r.nextInt(maxHeight - minHeight + 1) + minHeight; // from 40 to 140
    }
    public int getx(){
        return x;
    }
    public int gety(){
        return y;
    }
    public int getw(){
        return w;
    }
    public int geth(){
        return h;
    }
}
class BtnActPanel extends JPanel implements ActionListener{
//variables
   private JButton b1, b2, b3;     
   private JPanel background;
   private JPanel game;
   private Timer t, timer;
   private int x = 0, check1 = 0, index = 0, x1 = 650, count2 = 0,
   y2 = (int)(Math.random()*100)+40, y1 = (int)(Math.random()*100)+450, 
   x2 = (int)(Math.random()*600)+200, xaxis = 0, yaxis = 0, w = 0, h = 0, count = 0;
   private ImageIcon []arrImage;
   private boolean check2;
   private static ImageIcon icon, exitButton, startButton, questionButton, b, instruct, c ;


   public BtnActPanel(){    

      c = new ImageIcon("character.png");   // constructor
      t = new Timer (100,this);
      arrImage = new ImageIcon[2];
      arrImage[0] = new ImageIcon("character.png");
      arrImage[1] = new ImageIcon("character2.png");

      startButton = new ImageIcon("startButton.png");//start button image
      questionButton = new ImageIcon("QuestionButton.png"); //question button image
      exitButton = new ImageIcon("exitButton.png"); //exit button image

      icon = new ImageIcon("Title.jpg");//title image

      b1 = new JButton(questionButton); // creates first button
      //only shows button image with borders
      b1.setOpaque(false);
      b1.setContentAreaFilled(false);
      b1.setBorderPainted(false);
      b1.setFocusPainted(false);

      b2 = new JButton(startButton);// creates second button
      //only shows button image with borders
      b2.setOpaque(false);
      b2.setContentAreaFilled(false);
      b2.setBorderPainted(false);
      b2.setFocusPainted(false);

      b3 = new JButton(exitButton);// creates third button
      //only shows button image with borders
      b3.setOpaque(false);
      b3.setContentAreaFilled(false);
      b3.setBorderPainted(false);
      b3.setFocusPainted(false);

      //adds buttons to code
      this.add(b1);
      this.add(b2);
      this.add(b3);

      b1.addActionListener(this);
      b2.addActionListener(this);
      b3.addActionListener(this);
   }// end of constructor

    public void actionPerformed(ActionEvent e) { //checks which button the user presses and performs actions based off choice
              if(e.getSource() == b1){
                check1 = 2;
                this.remove(b1);
                this.remove(b3);
                repaint();
                instruct = new ImageIcon("Instructions.jpg");
              }
              else if (e.getSource() == b2){
                t.start();
                check1 = 1;
                this.remove(b1);
                this.remove(b2);
                this.remove(b3);
                repaint();
                b = new ImageIcon("toskyline.png");


              }

              else  if (e.getSource() == b3){
                JOptionPane.showMessageDialog(null, "This is an exit button, hope you enjoyed the game! :)", "Exit message",JOptionPane.WARNING_MESSAGE ); //shows exit message
                System.exit(0);//exits program
              } 

              else if (e.getSource() == t){
                  if (index == 0){
                      index = 1;
                      c = arrImage[1];
                  }
                  else{
                      index = 0;
                      c = arrImage[0];
                  }
                if(count%50 == 0 && count >= 50){
                    Rectangle obstacle = new Rectangle();
                    int xaxis = obstacle.getx();
                    int yaxis = obstacle.gety();
                    int w = obstacle.getw();
                    int h = obstacle.geth();
                    xaxis = xaxis - 10;
                    count2 = 1;
                }   
                x = x - 10;
                x1 = x1 - 10;
                repaint();
              }   
    }


    public void paintComponent(Graphics g){//this method draws and paints images and icons based on the user decisions
        super.paintComponent(g);
        if(check1 == 0)[enter image description here][1]
            g.drawImage(icon.getImage(),0,0,null);
        if(check1 == 1){
            g.drawImage(b.getImage(),0,0,null);
            g.setColor(Color.black);
            g.fillRect(x,495, 500, 35);
            g.fillRect(x1, y1, x2, y2);
            count++;
            System.out.println(count);
            if(count2 == 1){
                g.fillRect(xaxis, yaxis, w, h);
                count2 = 0;
            }
            g.drawImage(c.getImage(), 100, 460, null);
        }

        if(check1 == 2)
            g.drawImage(instruct.getImage(),0,0,null);
        b1.setBounds(320, 350, 100, 100);
        b2.setBounds(420, 350, 100, 100);
        b3.setBounds(520, 350, 100, 100);
    }
}//end of class

Answer 1

使用你的范围我做了一个演示。

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.RenderingHints;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.Timer;

public class Demo extends JPanel implements ActionListener {
    final static int height = 800;
    final static int width = 800;
    final static String title = "title";
    JFrame frame = new JFrame("default title");
    Timer timer;
    static Random r = new Random();
    static int upperX = 100;
    static int lowerX = 20;
    static int upperY = 550;
    static int lowerY = 450;
    static int minWidth = 200;
    static int maxWidth = 600;
    static int minHeight = 40;
    static int maxHeight = 140;
    List<MyRectangle> rectangles = new ArrayList<>();

    public static void main(String[] args) {
        SwingUtilities
                .invokeLater(() -> new Demo().start());
    }

    public Demo() {
        frame.setDefaultCloseOperation(
                JFrame.EXIT_ON_CLOSE);
        frame.add(this);
        frame.setPreferredSize(
                new Dimension(width, height));
        setBackground(Color.WHITE);
        frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }

    public void start() {
        timer = new Timer(0, this);
        timer.setDelay(1000);
        timer.start();
    }

    public void actionPerformed(ActionEvent ae) {
        rectangles.add(createRectangle());
        repaint();
    }

    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        Graphics2D g2d = (Graphics2D) g.create();
        g2d.setRenderingHint(
                RenderingHints.KEY_ANTIALIASING,
                RenderingHints.VALUE_ANTIALIAS_ON);
        for (MyRectangle r : rectangles) {
            g2d.setColor(Color.black);
            g2d.drawRect(r.x, r.y, r.width, r.height);
            g2d.setColor(r.color);
            g2d.fillRect(r.x+1, r.y+1, r.width-1,r.height-1);
        }
        g2d.dispose();

    }

    Color[] colors = {Color.RED, Color.BLUE, Color.GREEN, Color.ORANGE, Color.GRAY};
    int color = 0;
    public MyRectangle createRectangle() {
        int y = r.nextInt(upperY - lowerY + 1) + lowerY; // from 450 to 550
        int w = r.nextInt(maxWidth - minWidth + 1)
                + minWidth; // from 200 to 600
        int h = r.nextInt(maxHeight - minHeight + 1)
                + minHeight; // from 40 to 140
        int x = r.nextInt(upperX - lowerX + 1) + lowerX;
        Color c = colors[color++ % colors.length];
        return new MyRectangle(c, x, y, w, h);
    }

    class MyRectangle extends Rectangle {
       Color color; 
       MyRectangle(Color c, int x, int y, int w, int h) {
           super(x, y, w, h);
           this.color = c;
       }
    }

}

这扩展了 JDK 类 Rectangle 并向子类添加了颜色字段。它立即显示一个新的矩形。