Question

我正在试图找出线程和动画，所以我做了这个非常基本的程序，你可以按下按钮上下移动一个矩形。问题是如果你一直按下UP按钮直到矩形到达屏幕顶部，突然会出现一个额外的蓝色矩形。

这个问题有点难以解释只需运行程序并继续按UP，当你到达顶部时突然出现2个矩形。这是我的油漆组件的问题吗？

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.FlowLayout;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class RectangleMovement implements Runnable {
    JFrame frame;
    MyPanel panel;
    private int x = 100;
    private int y = 100;
    private int playerX = 400;
    private int playerY = 350;
    private int horizontalGoal = 0;
    private int verticalGoal = 0;

    public static void main(String[] args) {

            new RectangleMovement().go();

    }

    private void go() {
            frame = new JFrame("Worst Game Ever");
            panel = new MyPanel();
            MyPanel buttonPanel = new MyPanel();
            JButton left = new JButton("Left");
            JButton right = new JButton("Right");
            JButton down = new JButton("Down");
            JButton up = new JButton("Up");
            left.addActionListener(new LeftButton());
            right.addActionListener(new RightButton());
            down.addActionListener(new DownButton());
            up.addActionListener(new UpButton());
            buttonPanel.setLayout(new FlowLayout());
            buttonPanel.add(left);
            buttonPanel.add(down);
            buttonPanel.add(up);
            buttonPanel.add(right);

            frame.getContentPane().add(BorderLayout.CENTER, panel);
            frame.getContentPane().add(BorderLayout.SOUTH, buttonPanel);
            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            frame.setResizable(false);
            frame.setSize(500, 500);
            frame.setLocationRelativeTo(null);
            frame.setVisible(true);

            Thread player = new Thread(this);
            player.start();
            animate();
    }

    private class MyPanel extends JPanel {
            /**
             *
             */
            private static final long serialVersionUID = 1L;

            public void paintComponent(Graphics g) {
                    g.setColor(Color.RED);
                    g.fillRect(x, y, 10, 10);
                    g.setColor(Color.BLUE);
                    g.fillRect(playerX, playerY, 10, 10);
            }
    }

    class LeftButton implements ActionListener {

            @Override
            public void actionPerformed(ActionEvent e) {
                    horizontalGoal = -5;
            }
    }

    class RightButton implements ActionListener {

            @Override
            public void actionPerformed(ActionEvent e) {
                    horizontalGoal = 5;
            }
    }

    class UpButton implements ActionListener {

            @Override
            public void actionPerformed(ActionEvent e) {
                    verticalGoal = -5;
            }
    }

    class DownButton implements ActionListener {

            @Override
            public void actionPerformed(ActionEvent e) {
                    verticalGoal = 5;
            }
    }

    /*
     * Animates the player
     */
    public void run() {
            while (true) {
                    if (horizontalGoal < 0 && playerX > 0) {
                            playerX--;
                            horizontalGoal++;
                    } else if (horizontalGoal > 0 && playerX + 20 < frame.getWidth()) {
                            playerX++;
                            horizontalGoal--;
                    }
                    if (verticalGoal < 0 && playerY > 0) {
                            playerY--;
                            verticalGoal++;
                    } else if (verticalGoal > 0 && playerY + 10 < 400) {
                            playerY++;
                            verticalGoal--;
                    }
                    try {
                            Thread.sleep(15);
                    } catch (InterruptedException e) {
                            e.printStackTrace();
                    }
                    if (intersects()){
                            playerX = 400;
                            playerY = 350;
                    }
                    frame.repaint();
            }
    }

    private void animate() {
            boolean direction = true;
            while (true) {
                    if (y <= 100) {
                            direction = true;
                    } else if (y >= 400) {
                            direction = false;
                    }
                    if (direction) {
                            y++;
                    } else {
                            y--;
                    }
                    try {
                            Thread.sleep(15);
                    } catch (InterruptedException e) {
                            e.printStackTrace();
                    }
                    frame.repaint();
            }
    }

    private boolean intersects() {
            if (x <= playerX && playerX <= x + 10 && y <= playerY
                            && playerY <= y + 10) {
                    return true;
            }
            return false;
    }
}

Answer 1

你的buttonPanel就是问题所在。它也是一个使用您自己的paintComponent方法的MyPanel。因此，如果您的玩家应该被绘制，则玩家Y = 10.它会在您的游戏面板和您的buttonPanel上绘制。从

更改ButtonPanel

 MyPanel buttonPanel = new MyPanel();

到

Panel buttonPanel = new Panel();

你的问题消失了： - ）

Java中意外的额外动画

1 个答案: