java - 找不到符号: implements Drawable

Question

我正在尝试为我创建的每个角斗士对象进行自定义绘图，然后移动它们。我目前在有关关键字 Drawable 的“public class Gladiator Implements Drawable{”上的 Gladiator 类中遇到找不到符号错误。我很确定我正在导入我需要的东西(可能更多)...

public class Test2 extends JFrame {

private PaintPanel paintPanel;
public Test2() {
    setDefaultCloseOperation(EXIT_ON_CLOSE);
    setMinimumSize(new Dimension(800, 600));
    paintPanel = new  PaintPanel();
    getContentPane().add(paintPanel, BorderLayout.CENTER);
    pack();
    paintPanel.initGame();
}
class PaintPanel extends JPanel implements ActionListener {
    private List<Gladiator> gladiators;
    private Timer timer;

    public void initGame() {

        timer = new Timer(50, this);
        timer.start();

    }       
    @Override
    public void actionPerformed(ActionEvent e) {
        repaint();
        System.out.println("Refreshing ");
    }

    public PaintPanel(){
        super();
        gladiators = new ArrayList<Gladiator>();

    }

    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        Graphics2D g2 = (Graphics2D)g;
        for (Gladiator s : gladiators){
            g2.draw(s);
        }
    }
}
public static void main(String args[]) {
    java.awt.EventQueue.invokeLater(new Runnable() {
        public void run() {
            Test2 gamePanel = new Test2();
            gamePanel.setVisible(true);

        }
    });
}

}

角斗士等级:

import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.Shape;
import java.util.ArrayList;
import java.util.List;
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;

public class Gladiator implements Drawable {

    int minreach = 60;
    int maxreach = 100;
    int z = maxreach * 2;
    int n = minreach * 2;
    int[] location = new int[] {25,25};

    public void Draw(Graphics g){
            g.setColor(Color.green);
            g.fillArc(location[0], location[1], z, z, 45, 90);
            g.setColor(Color.red);
            g.fillArc((location[0]+(z-n)/2),(location[1]+(z-n)/2), n, n, 45, 90);
            g.setColor(Color.black);
            g.fillArc((location[0]+(z-30)/2),(location[1]+(z-30)/2), 30, 30, 0, 360);
    }

}

为什么我会收到此错误？我需要能够将我的角斗士绘制到屏幕上。我是否需要为我的视觉表示(抽象？)和我的游戏对象提供单独的类，就像我读过的一些教程似乎建议的那样？

编辑:

我完全删除了drawable，因为我认为它只是java语法的一部分，我什至可能不需要它。这是代码:

public class Test2 extends JFrame {

private PaintPanel paintPanel;
public Test2() {
    setDefaultCloseOperation(EXIT_ON_CLOSE);
    setMinimumSize(new Dimension(800, 600));
    paintPanel = new  PaintPanel();
    getContentPane().add(paintPanel, BorderLayout.CENTER);
    pack();
    paintPanel.initGame();
}
class PaintPanel extends JPanel implements ActionListener {
    private List<Gladiator> gladiators;
    private Timer timer;

    public void initGame() {

        timer = new Timer(50, this);
        timer.start();

    }       
    @Override
    public void actionPerformed(ActionEvent e) {
        repaint();
        System.out.println("Refreshing ");
    }

    public PaintPanel(){
        super();
        gladiators = new ArrayList<Gladiator>();

    }

    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        Graphics2D g2 = (Graphics2D)g;
        for (Gladiator s : gladiators){
            g2.draw(s);
        }
    }
}
public static void main(String args[]) {
    java.awt.EventQueue.invokeLater(new Runnable() {
        public void run() {
            Test2 gamePanel = new Test2();
            gamePanel.setVisible(true);

        }
    });
}

}

角斗士等级:

import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.Shape;
import java.util.ArrayList;
import java.util.List;
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;

public class Gladiator {

    int minreach = 60;
    int maxreach = 100;
    int z = maxreach * 2;
    int n = minreach * 2;
    int[] location = new int[] {25,25};

    public void Draw(Graphics g){
            g.setColor(Color.green);
            g.fillArc(location[0], location[1], z, z, 45, 90);
            g.setColor(Color.red);
            g.fillArc((location[0]+(z-n)/2),(location[1]+(z-n)/2), n, n, 45, 90);
            g.setColor(Color.black);
            g.fillArc((location[0]+(z-30)/2),(location[1]+(z-30)/2), 30, 30, 0, 360);
    }

}

我现在的错误出现在“g2.draw(s);”行上并表示“实际参数 Gladiator 无法通过方法调用转换转换为 Shape”。感谢您的帮助...如何将我的角斗士转换为形状？或者我应该以某种方式扩展 Shape ？

Answer 1

任何属于核心 Java 一部分的“事物”都可以在 Java API 中找到。如果你查找 API，你会发现 Drawable 不存在。当您遇到此类错误时，API 应该是您首先查看的地方。

<小时/>

编辑
您在编辑中声明:

My error now is on line "g2.draw(s);" and says "actual argument Gladiator cannot be converted to Shape by method invocation conversion". Thanks for any help... how to convert my Gladiator to a shape? Or should I be extending Shape somehow?

再次查看 API，这次是 Graphics2D 类。如果您使用其 draw(...) 方法，则必须遵循其规则，API 声明需要一个 Shape。您可以让 Gladiator 实现 Shape，但随后您需要实现许多方法。您还可以让它扩展从 Shape 派生的更具体的类之一。

或者也许您真正想要做的是调用传入 Graphics 对象的 Gladiator 对象上的绘制方法。

所以不是:

public void paintComponent(Graphics g) {
    super.paintComponent(g);
    Graphics2D g2 = (Graphics2D)g;
    for (Gladiator s : gladiators){
        g2.draw(s);
    }
}

而是

public void paintComponent(Graphics g) {
    super.paintComponent(g);
    Graphics2D g2 = (Graphics2D)g;
    for (Gladiator s : gladiators){
        s.draw(g2);  // note draw should *not* be capitalized!
    }
}