现在，敌舰按预期穿过屏幕。射击船不打算离开箱子。我一直试图用盒子的右侧来做，因为这就是我们的船开始的地方。任何投入都会很棒！我的代码：
import java.awt.*;
public class Project2 {
public static final int PATROL_Y = 250;
public static final int PATROL_SIZE = 20;
public static int patrolX = 270;
public static final int ENEMY_Y = 20;
public static final int ENEMY_SIZE = 30;
public static int enemyX = 0;
public static final int RIGHT_ARROW = 39;
public static final int LEFT_ARROW = 37;
public static final int UP_ARROW = 38;
//exe starts here
public static void main(String[] args) {
DrawingPanel panel = new DrawingPanel(300, 300);
Graphics g = panel.getGraphics( );
g.drawString("Project 2 by Garrett Griffin", 10, 15);
startGame(panel, g);
}
//Creates a patrol ship at x = patrolX,y=PATROL_Y, with side PATROL_SIZE in the given color
public static void drawPatrol(Graphics g, Color c){
g.setColor(Color.GREEN);
g.fillRect(patrolX, PATROL_Y, PATROL_SIZE, PATROL_SIZE);
}
//moveEnemyShipAndDraw: draws the enemy ship first in white, then increment enemyX by 1, then draws the ship in red again.
public static void moveEnemyShipAndDraw(Graphics g) {
g.setColor(Color.WHITE);
g.fillRect(enemyX, ENEMY_Y, ENEMY_SIZE, ENEMY_SIZE);
enemyX+=1;
g.setColor(Color.RED);
g.fillRect(enemyX, ENEMY_Y, ENEMY_SIZE, ENEMY_SIZE);
}
//incomplete
public static void handleKeys(DrawingPanel panel, Graphics g) {
//Set panel.getKeyCode(); to a variable. Any variable.
int i = panel.getKeyCode();
//if RA, move right 3 pixels
if (RIGHT_ARROW==i) {
g.setColor(Color.WHITE);
g.fillRect(patrolX, PATROL_Y, PATROL_SIZE, PATROL_SIZE);
patrolX+=3;
g.setColor(Color.GREEN);
g.fillRect(patrolX, PATROL_Y, PATROL_SIZE, PATROL_SIZE);
//if LA, move left 3 pixels
} else if(LEFT_ARROW==i) {
g.setColor(Color.WHITE);
g.fillRect(patrolX, PATROL_Y, PATROL_SIZE, PATROL_SIZE);
patrolX-=3;
g.setColor(Color.GREEN);
g.fillRect(patrolX, PATROL_Y, PATROL_SIZE, PATROL_SIZE);
//if zero, do nothing
} else if(i==0) {
g.setColor(Color.GREEN);
g.fillRect(patrolX, PATROL_Y, PATROL_SIZE, PATROL_SIZE);
//Keeps the patrolship from exiting the box
} else if(RIGHT_ARROW==i && patrolX==300) {
g.setColor(Color.GREEN);
g.fillRect(patrolX, PATROL_Y, PATROL_SIZE, PATROL_SIZE);
}
}
public static void startGame(DrawingPanel panel, Graphics g) {
int x = 0;
int y = 270;
int deltaX = 1;
int deltaY = -3;
drawPatrol(g, Color.green);
for (int time = 0; time <= 1000; time++) {
moveEnemyShipAndDraw(g);
handleKeys(panel, g);
panel.sleep(50);
}
}
}
导入我们用于创建图形的代码：
/*
Stuart Reges and Marty Stepp
February 24, 2007
Changes by Tom Bylander in 2010 (no anti-alias, repaint on sleep)
Changes by Tom Bylander in 2012 (track mouse clicks and movement)
Changes by Tom Bylander in 2013 (fix bug in tracking mouse clicks)
Changes by S. Robbins in 2014 (getters for width and height)
Changes by S. Robbins in 2014 (addKeyListener added)
Changes by S. Robbins in 2014 (catch exception on default close so that it works in an applet)
Changes by S. Robbins in 2015 (buffer key events)
Changes by S. Robbins in 2015 (show mouse status by default is off)
The DrawingPanel class provides a simple interface for drawing persistent
images using a Graphics object. An internal BufferedImage object is used
to keep track of what has been drawn. A client of the class simply
constructs a DrawingPanel of a particular size and then draws on it with
the Graphics object, setting the background color if they so choose.
To ensure that the image is always displayed, a timer calls repaint at
regular intervals.
*/
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;
}
}
}
您所要做的就是更改handlekeys方法中if语句的条件。
在"i"后面的第一个if语句中放入：&；patrolX<280
在第一个else-if语句中，在"i"之后放入：&；patrolX>0
此外，您不需要第三个else-if语句，因为该框现在将停止退出。