如何在Java中聆听按键时移动图像

你可以使用Swing计时器为图像设置动画：

import java.awt.*;import java.awt.event.*;import javax.swing.*;public class TimerAnimation extends JLabel implements ActionListener{ int deltaX = 2; int deltaY = 3; int directionX = 1; int directionY = 1; public TimerAnimation(int startX, int startY,int deltaX, int deltaY,int directionX, int directionY,int delay) {this.deltaX = deltaX;this.deltaY = deltaY;this.directionX = directionX;this.directionY = directionY;setIcon( new ImageIcon('dukewavered.gif') );// setIcon( new ImageIcon('copy16.gif') );setSize( getPreferredSize() );setLocation(startX, startY);new javax.swing.Timer(delay, this).start(); } public void actionPerformed(ActionEvent e) {Container parent = getParent();// Determine next X positionint nextX = getLocation().x + (deltaX * directionX);if (nextX < 0){ nextX = 0; directionX *= -1;}if ( nextX + getSize().width > parent.getSize().width){ nextX = parent.getSize().width - getSize().width; directionX *= -1;}// Determine next Y positionint nextY = getLocation().y + (deltaY * directionY);if (nextY < 0){ nextY = 0; directionY *= -1;}if ( nextY + getSize().height > parent.getSize().height){ nextY = parent.getSize().height - getSize().height; directionY *= -1;}// Move the labelsetLocation(nextX, nextY); } public static void main(String[] args) {JPanel panel = new JPanel();JFrame frame = new JFrame();frame.setContentPane(panel);frame.setDefaultCloSEOperation( JFrame.EXIT_ON_CLOSE );frame.getContentPane().setLayout(null);// frame.getContentPane().add( new TimerAnimation(10, 10, 2, 3, 1, 1, 10) );frame.getContentPane().add( new TimerAnimation(300, 100, 3, 2, -1, 1, 20) );// frame.getContentPane().add( new TimerAnimation(0, 000, 5, 0, 1, 1, 20) );frame.getContentPane().add( new TimerAnimation(0, 200, 5, 0, 1, 1, 80) );frame.setSize(400, 400);frame.setLocationRelativeto( null );frame.setVisible(true);// frame.getContentPane().add( new TimerAnimation(10, 10, 2, 3, 1, 1, 10) );// frame.getContentPane().add( new TimerAnimation(10, 10, 3, 0, 1, 1, 10) ); }}

你可以将KeyListener添加到面板，它将独立于图像动画进行操作。

是的，Swing计时器和键绑定可以很好地工作。这是另一个例子（我的）:)

import java.awt.*;import java.awt.event.*;import java.awt.image.BufferedImage;import javax.swing.*;public class AnimationWithKeyBinding { private static void createAndShowUI() { AnimationPanel panel = new AnimationPanel(); // the drawing JPanel JFrame frame = new JFrame('Animation With Key Binding'); frame.getContentPane().add(panel); frame.setDefaultCloSEOperation(JFrame.EXIT_ON_CLOSE); frame.pack(); frame.setLocationRelativeto(null); frame.setVisible(true); } public static void main(String[] args) { java.awt.EventQueue.invokelater(new Runnable() { public void run() { createAndShowUI(); } }); }}@SuppressWarnings('serial')class AnimationPanel extends JPanel { public static final int SPRITE_WIDTH = 20; public static final int PANEL_WIDTH = 400; public static final int PANEL_HEIGHT = 400; private static final int MAX_MSTATE = 25; private static final int SPIN_TIMER_PERIOD = 16; private static final int SPRITE_STEP = 3; private int mState = 0; private int mX = (PANEL_WIDTH - SPRITE_WIDTH) / 2; private int mY = (PANEL_HEIGHT - SPRITE_WIDTH) / 2; private int oldMX = mX; private int oldMY = mY; private boolean moved = false; // an array of sprite images that are drawn sequentially private BufferedImage[] spriteImages = new BufferedImage[MAX_MSTATE]; public AnimationPanel() { // create and start the main animation timer new Timer(SPIN_TIMER_PERIOD, new SpinTimerListener()).start(); setPreferredSize(new Dimension(PANEL_WIDTH, PANEL_HEIGHT)); setBackground(Color.white); createSprites(); // create the images setupKeyBinding(); } private void setupKeyBinding() { int condition = JComponent.WHEN_IN_FOCUSED_WINDOW; InputMap inMap = getInputMap(condition); ActionMap actMap = getActionMap(); // this uses an enum of Direction that holds ints for the arrow keys for (Direction direction : Direction.values()) { int key = direction.getKey(); String name = direction.name(); // add the key bindings for arrow key and shift-arrow key inMap.put(Keystroke.getKeystroke(key, 0), name); inMap.put(Keystroke.getKeystroke(key, InputEvent.SHIFT_DOWN_MASK), name); actMap.put(name, new MyKeyAction(this, direction)); } } // create a bunch of buffered images and place into an array, // to be displayed sequentially private void createSprites() { for (int i = 0; i < spriteImages.length; i++) { spriteImages[i] = new BufferedImage(SPRITE_WIDTH, SPRITE_WIDTH, BufferedImage.TYPE_INT_ARGB); Graphics2D g2 = spriteImages[i].createGraphics(); g2.setColor(Color.red); g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); double theta = i * Math.PI / (2 * spriteImages.length); double x = SPRITE_WIDTH * Math.abs(Math.cos(theta)) / 2.0; double y = SPRITE_WIDTH * Math.abs(Math.sin(theta)) / 2.0; int x1 = (int) ((SPRITE_WIDTH / 2.0) - x); int y1 = (int) ((SPRITE_WIDTH / 2.0) - y); int x2 = (int) ((SPRITE_WIDTH / 2.0) + x); int y2 = (int) ((SPRITE_WIDTH / 2.0) + y); g2.drawLine(x1, y1, x2, y2); g2.drawLine(y1, x2, y2, x1); g2.dispose(); } } @Override protected void paintComponent(Graphics g) { super.paintComponent(g); g.drawImage(spriteImages[mState], mX, mY, null); } public void incrementX(boolean right) { oldMX = mX; if (right) { mX = Math.min(getWidth() - SPRITE_WIDTH, mX + SPRITE_STEP); } else { mX = Math.max(0, mX - SPRITE_STEP); } moved = true; } public void incrementY(boolean down) { oldMY = mY; if (down) { mY = Math.min(getHeight() - SPRITE_WIDTH, mY + SPRITE_STEP); } else { mY = Math.max(0, mY - SPRITE_STEP); } moved = true; } public void tick() { mState = (mState + 1) % MAX_MSTATE; } private class SpinTimerListener implements ActionListener { @Override public void actionPerformed(ActionEvent e) { tick(); int delta = 20; int width = SPRITE_WIDTH + 2 * delta; int height = width; // make sure to erase the old image if (moved) { int x = oldMX - delta; int y = oldMY - delta; repaint(x, y, width, height); } int x = mX - delta; int y = mY - delta; // draw the new image repaint(x, y, width, height); moved = false; } }}enum Direction { UP(KeyEvent.VK_UP), DOWN(KeyEvent.VK_DOWN), LEFT(KeyEvent.VK_LEFT), RIGHT(KeyEvent.VK_RIGHT); private int key; private Direction(int key) { this.key = key; } public int getKey() { return key; }}// Actions for the key binding@SuppressWarnings('serial')class MyKeyAction extends AbstractAction { private AnimationPanel draw; private Direction direction; public MyKeyAction(AnimationPanel draw, Direction direction) { this.draw = draw; this.direction = direction; } @Override public void actionPerformed(ActionEvent e) { switch (direction) { case UP: draw.incrementY(false); break; case DOWN: draw.incrementY(true); break; case LEFT: draw.incrementX(false); break; case RIGHT: draw.incrementX(true); break; default: break; } }}

这是另一个使用此精灵表的示例：

在此处输入图片说明

从本网站获得。

同样，这是在JPanel的paintComponent方法中进行绘制并使用“键绑定”指示移动方向的示例。

import java.awt.Color;import java.awt.Dimension;import java.awt.Graphics;import java.awt.Image;import java.awt.event.*;import java.awt.image.BufferedImage;import java.io.IOException;import java.net.URL;import java.util.ArrayList;import java.util.EnumMap;import java.util.List;import java.util.Map;import javax.imageio.ImageIO;import javax.swing.*;@SuppressWarnings('serial')public class Mcve3 extends JPanel { private static final int PREF_W = 800; private static final int PREF_H = 640; private static final int TIMER_DELAY = 50; private int spriteX = 400; private int spriteY = 320; private SpriteDirection spriteDirection = SpriteDirection.RIGHT; private MySprite sprite = null; private Timer timer = null; public Mcve3() {try { sprite = new MySprite(spriteDirection, spriteX, spriteY);} catch (IOException e) { e.printstacktrace(); System.exit(-1);}setBackground(Color.WHITE);setKeyBindings(SpriteDirection.LEFT, KeyEvent.VK_LEFT);setKeyBindings(SpriteDirection.RIGHT, KeyEvent.VK_RIGHT);setKeyBindings(SpriteDirection.FORWARD, KeyEvent.VK_DOWN);setKeyBindings(SpriteDirection.AWAY, KeyEvent.VK_UP);timer = new Timer(TIMER_DELAY, new TimerListener());timer.start(); } private void setKeyBindings(SpriteDirection dir, int keyCode) {int condition = WHEN_IN_FOCUSED_WINDOW;InputMap inputMap = getInputMap(condition);ActionMap actionMap = getActionMap();Keystroke keypressed = Keystroke.getKeystroke(keyCode, 0, false);Keystroke keyreleased = Keystroke.getKeystroke(keyCode, 0, true);inputMap.put(keypressed, keypressed.toString());inputMap.put(keyreleased, keyreleased.toString());actionMap.put(keypressed.toString(), new MoveAction(dir, false));actionMap.put(keyreleased.toString(), new MoveAction(dir, true)); } @Override public Dimension getPreferredSize() {if (isPreferredSizeSet()) { return super.getPreferredSize();}return new Dimension(PREF_W, PREF_H); } @Override protected void paintComponent(Graphics g) {super.paintComponent(g);sprite.draw(g); } private class MoveAction extends AbstractAction {private SpriteDirection dir;private boolean released;public MoveAction(SpriteDirection dir, boolean released) { this.dir = dir; this.released = released;}@Overridepublic void actionPerformed(ActionEvent e) { if (released) {sprite.setMoving(false); } else {sprite.setMoving(true);sprite.setDirection(dir); }} } private class TimerListener implements ActionListener {@Override public void actionPerformed(ActionEvent e) {if (sprite.isMoving()) { sprite.tick();}repaint(); } } private static void createAndShowGui() {Mcve3 mainPanel = new Mcve3();JFrame frame = new JFrame('MCVE');frame.setDefaultCloSEOperation(JFrame.EXIT_ON_CLOSE);frame.getContentPane().add(mainPanel);frame.pack();frame.setLocationRelativeto(null);frame.setVisible(true); } public static void main(String[] args) {SwingUtilities.invokelater(() -> createAndShowGui()); }}class MySprite { private static final String SPRITE_SHEET_PATH = 'http://' + 'orig12.deviantart.net/7db3/f/2010/338/3/3/' + 'animated_sprite_sheet_32x32_by_digibody-d3479l2.gif'; private static final int MAX_MOVING_INDEX = 4; private static final int DELTA = 4; private SpriteDirection direction; private Map<SpriteDirection, Image> standingImgMap = new EnumMap<>(SpriteDirection.class); private Map<SpriteDirection, List<Image>> movingImgMap = new EnumMap<>(SpriteDirection.class); private int x; private int y; private boolean moving = false; private int movingIndex = 0; public MySprite(SpriteDirection direction, int x, int y) throws IOException {this.direction = direction;this.x = x;this.y = y;createSprites(); } public void draw(Graphics g) {Image img = null;if (!moving) { img = standingImgMap.get(direction);} else { img = movingImgMap.get(direction).get(movingIndex);}g.drawImage(img, x, y, null); } private void createSprites() throws IOException {URL spriteSheetUrl = new URL(SPRITE_SHEET_PATH);BufferedImage img = ImageIO.read(spriteSheetUrl);// get sub-images (sprites) from the sprite sheet// magic numbers for getting sprites from sheet, all obtained by trial and errorint x0 = 0;int y0 = 64;int rW = 32;int rH = 32;for (int row = 0; row < 4; row++) { SpriteDirection dir = SpriteDirection.values()[row]; List<Image> imgList = new ArrayList<>(); movingImgMap.put(dir, imgList); int rY = y0 + row * rH; for (int col = 0; col < 5; coL++) {int rX = x0 + col * rW;BufferedImage subImg = img.getSubimage(rX, rY, rW, rH);if (col == 0) { // first image is standing standingImgMap.put(dir, subImg);} else { // all others are moving imgList.add(subImg);} }} } public SpriteDirection getDirection() {return direction; } public void setDirection(SpriteDirection direction) {if (this.direction != direction) { setMoving(false);}this.direction = direction; } public int getX() {return x; } public void setX(int x) {this.x = x; } public int getY() {return y; } public void setY(int y) {this.y = y; } public boolean isMoving() {return moving; } public void setMoving(boolean moving) {this.moving = moving;if (!moving) { movingIndex = 0;} } public void tick() {if (moving) { switch (direction) { case RIGHT:x += DELTA;break; case LEFT:x -= DELTA;break; case FORWARD:y += DELTA;break; case AWAY:y -= DELTA; } movingIndex++; movingIndex %= MAX_MOVING_INDEX;} } public int getMovingIndex() {return movingIndex; } public void setMovingIndex(int movingIndex) {this.movingIndex = movingIndex; }}enum SpriteDirection { FORWARD, LEFT, AWAY, RIGHT}解决方法

我开始学习Java编程，并且我认为通过游戏开发学习Java很酷。我知道如何绘制图像并听按键，然后移动该图像。但是，当窗口正在听按键时，是否可以使图像在窗口中来回移动？例如，当图像或对象（如太空飞船）在窗口中从左向右移动时，如果按空格键，激光将在屏幕底部发射（很酷的：D）。但是基本上，我只是想知道在窗口正在听按键时如何使图像左右移动。

我在想将一个关键侦听器添加到我的窗口，然后触发一个无限循环来移动图像。还是我需要学习有关线程的知识，以便另一个线程可以移动对象？

请指教。