4

I am trying to move a train across my java window and am having serious problems. I have a Train class in which I made the train, and a Driver class which is supposed to move the train. I need to make the whole train move from right to left until it 'passes' the left edge of the screen. Then add an if statement to change the dx so the train restarts on the right side . The below is what I have tried but it is not working. Can anyone help me please??

public class Driver extends GraphicsProgram
{
    //~ Instance/static variables .............................................

    private static final int N_STEPS = 1000;
    private static final int PAUSE_TIME = 20;
    private static final double TRAIN_LENGTH = 320;

    //~ Constructor ...........................................................

    // ----------------------------------------------------------
    /**
     * The run() method of the Driver Class.
     * Creates an instance of the Train Class.
     * Responsible for animating the train across the screen.
     */
    public void run()
    {
        Train train = new Train(getGCanvas());
        for (int i = 0; i < N_STEPS; i++) {
            train.move(-100, 0);
            pause(PAUSE_TIME);
    }
4

2 回答 2

3

这是一个用swing制作的小演示。只需将黑色矩形替换为您的火车图像即可。

诀窍是使用单独的线程（或计时器）来执行动画循环（通常称为game loop）。该循环仅告诉您的窗口重绘自身，并且在每次重绘时，您首先计算动画对象的新位置，然后绘制它们。

import javax.swing.*;
import java.awt.*;

public class TrainDemo {

    public static void main(String[] args) {
        JFrame frame = new JFrame("Train Demo");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(800, 400);
        frame.setLocationRelativeTo(null);
        frame.add(new TrainCanvas());
        frame.setVisible(true);
    }

}

class TrainCanvas extends JComponent {

    private int lastX = 0;

    public TrainCanvas() {
        Thread animationThread = new Thread(new Runnable() {
            public void run() {
                while (true) {
                    repaint();
                    try {Thread.sleep(10);} catch (Exception ex) {}
                }
            }
        });

        animationThread.start();
    }

    public void paintComponent(Graphics g) {
        Graphics2D gg = (Graphics2D) g;

        int w = getWidth();
        int h = getHeight();

        int trainW = 100;
        int trainH = 10;
        int trainSpeed = 3;

        int x = lastX + trainSpeed;

        if (x > w + trainW) {
            x = -trainW;
        }

        gg.setColor(Color.BLACK);
        gg.fillRect(x, h/2 + trainH, trainW, trainH);

        lastX = x;
    }

}
于 2013-10-28T09:02:44.707 回答
-1 
color c = color(0); float x = 0; float y = 100; float speed = 1;
void setup() { size(200,200); }
void draw() { background(255); move(); display(); }
void move() { x = x + speed; if (x > width) { x = 0; } }
void display() { fill(c); rect(x,y,30,10); }
于 2019-03-08T19:47:39.903 回答