Question

这些是具体的指示，但它们让我感到困惑（指令令人困惑/模棱两可，还是我没有得到它？）

写一个方法public static void draw shooter（Graphics g，Color c）; 使用射手颜色作为drawAll（？）中的最后一个参数来调用绘制射手测试程序你应该看到一个红色磁盘居中靠近屏幕的底部（？）

import java.awt.*;

public class Project2{
  public static final int PANEL_WIDTH = 300;
  public static final int PANEL_HEIGHT = 300;
  public static final int SLEEP_TIME = 50;
  public static Color SHOOTER_COLOR = Color.RED;
  public static Color BACKGROUND_COLOR = Color.WHITE;
  public static final int SHOOTER_SIZE = 20; //diameter of the shooter
  public static final int GUN_SIZE = 10; //length og the gun
  public static final int SHOOTER_POSITION_Y = PANEL_HEIGHT - SHOOTER_SIZE;
  public static final int SHOOTER_INITIAL_POSITION_X = 150;
  int shooterPosition;

  public static void initialize(){
    int shooterPositionX = SHOOTER_INITIAL_POSITION_X;
  }

  public static void main(String[] args) {
    DrawingPanel panel = new DrawingPanel(PANEL_WIDTH, PANEL_HEIGHT);
    Graphics g = panel.getGraphics( );
    initialize();
    startGame(panel, g);
    drawShooter(g, SHOOTER_COLOR);
  }

  public static void drawShooter(Graphics g, Color C){
    g.setColor(Color);
    g.fillOval(shooterPosition, SHOOTER_POSITION_Y, SHOOTER_SIZE, SHOOTER_SIZE);
  }

  public static void drawAll(Graphics g){
    g.drawString("Project 2 by Jasmine Ramirez", 10, 15);
  }

  public static void startGame(DrawingPanel panel, Graphics g) {

    for (int i = 0; i <= 10000; i++) {
      panel.sleep(SLEEP_TIME);
      drawAll(g);
    }
  }
}

这是我的代码我猜我需要在方法内的圆圈中绘制和着色，但是我在方法中遇到了g.setColor错误，我不确定第二步意味着什么。谢谢你刚开始学习编程。

绘图面板

import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
import javax.swing.*;
import javax.swing.event.*;
import java.util.ArrayList;

public class DrawingPanel implements ActionListener {
 private static final String versionMessage = 
    "Drawing Panel version 1.1, January 25, 2015";
 private static final int DELAY = 100;  // delay between repaints in millis
 private static final boolean PRETTY = false;  // true to anti-alias
 private static boolean showStatus = false;
 private static final int MAX_KEY_BUF_SIZE = 10;

 private int width, height;    // dimensions of window frame
 private JFrame frame;         // overall window frame
 private JPanel panel;         // overall drawing surface
 private BufferedImage image;  // remembers drawing commands
 private Graphics2D g2;        // graphics context for painting
 private JLabel statusBar;     // status bar showing mouse position
 private volatile MouseEvent click;     // stores the last mouse click
 private volatile boolean pressed;      // true if the mouse is pressed
 private volatile MouseEvent move;      // stores the position of the mouse
 private ArrayList<KeyInfo> keys;

 // construct a drawing panel of given width and height enclosed in a window
 public DrawingPanel(int width, int height) {
   this.width = width;
   this.height = height;
   keys = new ArrayList<KeyInfo>();
   image = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);

   statusBar = new JLabel(" ");
   statusBar.setBorder(BorderFactory.createLineBorder(Color.BLACK));
   statusBar.setText(versionMessage);

   panel = new JPanel(new FlowLayout(FlowLayout.CENTER, 0, 0));
   panel.setBackground(Color.WHITE);
   panel.setPreferredSize(new Dimension(width, height));
   panel.add(new JLabel(new ImageIcon(image)));

   click = null;
   move = null;
   pressed = false;

   // listen to mouse movement
   MouseInputAdapter listener = new MouseInputAdapter() {
     public void mouseMoved(MouseEvent e) {
       pressed = false;
       move = e;
       if (showStatus)
          statusBar.setText("moved (" + e.getX() + ", " + e.getY() + ")");
     }

     public void mousePressed(MouseEvent e) {
       pressed = true;
       move = e;
       if (showStatus)
          statusBar.setText("pressed (" + e.getX() + ", " + e.getY() + ")");
     }

     public void mouseDragged(MouseEvent e) {
       pressed = true;
       move = e;
       if (showStatus)
          statusBar.setText("dragged (" + e.getX() + ", " + e.getY() + ")");
     }

     public void mouseReleased(MouseEvent e) {
       click = e;
       pressed = false;
       if (showStatus)
          statusBar.setText("released (" + e.getX() + ", " + e.getY() + ")");
     }

     public void mouseEntered(MouseEvent e) {
//       System.out.println("mouse entered");
       panel.requestFocus();
     }

   };
   panel.addMouseListener(listener);
   panel.addMouseMotionListener(listener);
   new DrawingPanelKeyListener();

   g2 = (Graphics2D)image.getGraphics();
   g2.setColor(Color.BLACK);
   if (PRETTY) {
     g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
     g2.setStroke(new BasicStroke(1.1f));
   }

   frame = new JFrame("Drawing Panel");
   frame.setResizable(false);
   try {
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); // so that this works in an applet
   } catch (Exception e) {}
   frame.getContentPane().add(panel);
   frame.getContentPane().add(statusBar, "South");
   frame.pack();
   frame.setVisible(true);
   toFront();
   frame.requestFocus();

   // repaint timer so that the screen will update
   new Timer(DELAY, this).start();
 }

 public void showMouseStatus(boolean f) {
   showStatus = f;
 }

 public void addKeyListener(KeyListener listener) {
   panel.addKeyListener(listener);
   panel.requestFocus();
 }

 // used for an internal timer that keeps repainting
 public void actionPerformed(ActionEvent e) {
   panel.repaint();
 }

 // obtain the Graphics object to draw on the panel
 public Graphics2D getGraphics() {
   return g2;
 }

 // set the background color of the drawing panel
 public void setBackground(Color c) {
   panel.setBackground(c);
 }

 // show or hide the drawing panel on the screen
 public void setVisible(boolean visible) {
   frame.setVisible(visible);
 }

 // makes the program pause for the given amount of time,
 // allowing for animation
 public void sleep(int millis) {
   panel.repaint();
   try {
     Thread.sleep(millis);
   } catch (InterruptedException e) {}
 }

 // close the drawing panel
 public void close() {
   frame.dispose();
 }

 // makes drawing panel become the frontmost window on the screen
 public void toFront() {
   frame.toFront();
 }

 // return panel width
 public int getWidth() {
    return width;
 }

 // return panel height
 public int getHeight() {
    return height;
 }

 // return the X position of the mouse or -1
 public int getMouseX() {
   if (move == null) {
     return -1;
   } else {
     return move.getX();
   }
 }

 // return the Y position of the mouse or -1
 public int getMouseY() {
   if (move == null) {
     return -1;
   } else {
     return move.getY();
   }
 }

 // return the X position of the last click or -1
 public int getClickX() {
   if (click == null) {
     return -1;
   } else {
     return click.getX();
   }
 }

 // return the Y position of the last click or -1
 public int getClickY() {
   if (click == null) {
     return -1;
   } else {
     return click.getY();
   }
 }

 // return true if a mouse button is pressed
 public boolean mousePressed() {
   return pressed;
 }

 public synchronized int getKeyCode() {
   if (keys.size() == 0)
     return 0;
   return keys.remove(0).keyCode;
 }

  public synchronized char getKeyChar() {
   if (keys.size() == 0)
     return 0;
   return keys.remove(0).keyChar;
 }

  public synchronized int getKeysSize() {
    return keys.size();
  }

 private synchronized void insertKeyData(char c, int code) {
   keys.add(new KeyInfo(c,code));
   if (keys.size() > MAX_KEY_BUF_SIZE) {
     keys.remove(0);
//     System.out.println("Dropped key");
   }
 }

 private class KeyInfo {
   public int keyCode;
   public char keyChar;

   public KeyInfo(char keyChar, int keyCode) {
     this.keyCode = keyCode;
     this.keyChar = keyChar;
   }
 }

 private class DrawingPanelKeyListener implements KeyListener {

   int repeatCount = 0;

   public DrawingPanelKeyListener() {
     panel.addKeyListener(this);
     panel.requestFocus();
   }

   public void keyPressed(KeyEvent event) {
//     System.out.println("key pressed");
     repeatCount++;
     if ((repeatCount == 1) || (getKeysSize() < 2))
        insertKeyData(event.getKeyChar(),event.getKeyCode());
   }

   public void keyTyped(KeyEvent event) {
   }

   public void keyReleased(KeyEvent event) {
     repeatCount = 0;
   }

 }

}

Answer 1

第一次错误

使用drawShooter()方法：

g.setColor(Color)

这是不正确的，因为你需要传递类Color的实例而不是类本身。

所以改为使用：

g.setColor(C);

第二次错误

将shooterPosition更改为static，以便可以通过静态方法访问它。我假设方法initialize()也是错误的，因为你无缘无故地声明一个新的shooterPosition int，所以这些更改：

int shooterPosition;

要：

public static int shooterPosition;

和

public static void initialize(){ int shooterPositionX = SHOOTER_INITIAL_POSITION_X; }

要：

public static void initialize() {
    shooterPosition = SHOOTER_INITIAL_POSITION_X;
}

第三次错误

在startGame()中，你循环10000次，每次等待的时间超过1/20秒，这意味着你必须等待近10分钟，直到红圈为画。所以你有两个选择。

第一个选项：减少迭代次数，甚至更好地删除循环。

public static void startGame(DrawingPanel panel, Graphics g) { for (int i = 0; i <= 10000; i++) { panel.sleep(SLEEP_TIME); drawAll(g); } }

要：

public static void startGame(DrawingPanel panel, Graphics g) {
    for (int i = 0; i <= 1; i++) {
        panel.sleep(SLEEP_TIME);
        drawAll(g);
    }
}

或

public static void startGame(DrawingPanel panel, Graphics g) {
        panel.sleep(SLEEP_TIME);
        drawAll(g);
}

第二个选项：在drawShooter()方法之前执行startGame()方法，或者根本不执行startGame()。

startGame(panel, g); drawShooter(g, SHOOTER_COLOR);

要：

drawShooter(g, SHOOTER_COLOR);
startGame(panel, g);

或

drawShooter(g, SHOOTER_COLOR);

Answer 2

你昨天没有问同样的问题或类似的问题吗？并且您将类名传递给g.setColor(Color)方法，并且需要传入包含该对象的参数：g.setColor(C)

你对图形的使用并不好，因为你不应该通过getGraphics()使用从组件中获得的图形，但我猜测它是因为那个＆＃39;你的导师告诉你的事情。使用while (true)循环也是如此。相反，你应该使用Swing Timer。

Answer 3

如前所述，g.setcolor（c）是必需的

检查你的错误消息，因为它允许你收集错误和shooterPosition错误（它不公开，所以不能在方法中使用）

我正在努力创造和理解一个简单射击游戏程序的具体方法

3 个答案:

第一次错误

第二次错误

第三次错误