java - 在网格顶部绘图

Question

我正在尝试使用 Swing 在 Java 中制作迷宫游戏。我的迷宫采用网格布局，并尝试在其顶部绘制圆圈，但每当我绘制时，圆圈都会出现在网格下方。有什么办法可以改变这个吗？这是我第一次使用swing。 screenshot of my game

这是我的课:

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import java.util.*;
import javax.swing.plaf.LayerUI;

public class Light extends LayerUI<JPanel> implements KeyListener, ActionListener{
    private javax.swing.Timer myTimer;
    private ArrayList <Area> circles;
    private Color[] colours;
    private static double x,y,d,xV,yV,originalD,originalX,originalY;

    public Light(){
        x=200;
        y=200;
        d=70;
        xV=0;
        yV=0;
        circles = new ArrayList <Area>();
        colours = new Color[20];
        for (int i=0;i<20;i++) colours[i]=new Color(240-i*12,240-i*12,240-i*12);
        addKeyListener(this);
        setFocusable(true);
        myTimer = new javax.swing.Timer(120, this ); 
        myTimer.start();
    } 

    public void keyTyped(KeyEvent e) {}

    public void keyPressed(KeyEvent e) {
        int key = e.getKeyCode();
        if (key == KeyEvent.VK_UP) yV=-20;
        else if (key == KeyEvent.VK_DOWN) yV=20;
        else if (key == KeyEvent.VK_LEFT) xV=-20;
        else if (key == KeyEvent.VK_RIGHT) xV=20;
        repaint();
    }

    public void keyReleased(KeyEvent e) {
        int key = e.getKeyCode();
        if (key == KeyEvent.VK_UP) yV=0;
        else if (key == KeyEvent.VK_DOWN) yV=0;
        else if (key == KeyEvent.VK_LEFT) xV=0;
        else if (key == KeyEvent.VK_RIGHT) xV=0;
        repaint();
    }

    public void actionPerformed(ActionEvent e) {
        if (e.getSource()==myTimer) repaint();
    }

    private AlphaComposite makeComposite(float alpha) {
        int type = AlphaComposite.SRC_OVER;
        return(AlphaComposite.getInstance(type, alpha));
    }

    private void createCricles(Graphics2D g2d, float alpha,Color c,Area circle) {
        Composite originalComposite = g2d.getComposite();
        g2d.setPaint(c);
        g2d.setComposite(makeComposite(alpha));
        g2d.fill(circle);
        g2d.setComposite(originalComposite);
    }

    private void move(){
        x+=xV;
        y+=yV;
    }

    public double getLightX(){
        return x;
    }

    public double getLightY(){
        return y;
    }

    public void drawCircles(Graphics g,JComponent c) {
        super.paint(g,c);
        Graphics2D g2d = (Graphics2D)g;
        circles.clear();
        //more code here
    }
}

这些是我收到的错误:

./Light.java:23: error: cannot find symbol
        addKeyListener(this);
        ^
  symbol:   method addKeyListener(Light)
  location: class Light
./Light.java:24: error: cannot find symbol
        setFocusable(true);
        ^
  symbol:   method setFocusable(boolean)
  location: class Light
./Light.java:37: error: cannot find symbol
        repaint();
        ^
  symbol:   method repaint()
  location: class Light
./Light.java:46: error: cannot find symbol
        repaint();
        ^
  symbol:   method repaint()
  location: class Light
./Light.java:50: error: cannot find symbol
        if (e.getSource()==myTimer) repaint();
                                    ^
  symbol:   method repaint()
  location: class Light
5 errors

Answer 1

不要直接调用paintComponent()。当组件需要重新绘制时，Swing 将调用paintComponent()。

drawCircles(…) 是一个应该在 PaintComponent() 方法中调用的方法。

也许你可以使用Layered Pane在游戏面板顶部绘制圆圈。 Light 面板需要是不透明的，这样它的背景就不会覆盖游戏板。

或者您可以使用JLayer 。不太确定您想要达到什么效果。