Question

我可以在屏幕上绘制静态内容，但我希望通过用户键输入来移动它们。我不知道该怎么做，我一直在搜索和搜索，但还没有找到答案。请帮忙！

class User < ActiveRecord::Base
  has_many :records
end

class Record < ActiveRecord::Base
  belongs_to :user
  belongs_to :drop
end

class Drop < ActiveRecord::Base
  has_many :records
end

编辑： 修正了它。我在构造函数方法中删除了关键监听器的东西，在构造函数方法中添加了一个关注“drawingstuff”的命令，最重要的是，将这段代码添加到构造函数方法的末尾：

package com.Game.game;

import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;

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

public class Game extends JFrame
{

final static int width = 500;
final static int height = 500;

public int x = 250;
public int y = 250;
public int changeX = 10;
public int changeY = 10;

public static void main(String[] args)
{
    new Game();
}

public Game()
{
    KeyListener listener = new KeyListening();
    addKeyListener(listener);
    setFocusable(true);
    DrawingStuff drawingstuff = new DrawingStuff();
    add(drawingstuff);
    setSize(width, height);
    setLocationRelativeTo(null);
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setVisible(true);
}

public class DrawingStuff extends JPanel
{
    public void paintComponent(Graphics g)
    {
        super.paintComponent(g);
        g.drawString("Hey there!", 300, 300);
        g.setColor(Color.RED);
        g.fillRect(x, y, 50, 50);
    }
}

public class KeyListening implements KeyListener
{
    DrawingStuff drawingstuff = new DrawingStuff();
    @Override
    public void keyPressed(KeyEvent e) 
    {
        if(e.getKeyCode() == KeyEvent.VK_UP)
        {
            y = y + changeY;
            System.out.println("Hey");
            drawingstuff.repaint();
        }

    }
    @Override
    public void keyReleased(KeyEvent e) 
    {


    }
    @Override
    public void keyTyped(KeyEvent e) 
    {


    }
}


public void update()
{

}
}

Answer 1

问题是，您的KeyListening对象引用了与DrawingStuff构造函数中添加到UI的对象不同的Game对象。

public class KeyListening implements KeyListener
{
    DrawingStuff drawingstuff = new DrawingStuff();
    ...

您应该将DrawingStuff引用传递给KeyListening实例，以便它可以告诉正确的对象重绘自己。

我无法绘制对象并让它们在屏幕上移动

1 个答案: