当我运行代码时,添加的Example1类到JOptionPane(在Frame中)应该获得keyInput,然后更改播放器实例的y值(在example1中),但它不起作用.此外,我如何能够在其轴上旋转船舶,然后朝着其面向的方向移动？目前它沿着其旋转的方向移动,但它在看似坐标0,0的位置旋转.
帧
import javax.swing.*;
import java.awt.*;
/**
* Created by griffin on 12/7/2015.
*/
public class Frame extends JFrame {
public Frame() {
initUI();
}
private void initUI() {
JTabbedPane jtp = new JTabbedPane();
Example1 e1 = new Example1();
Example2 e2 = new Example2();
getContentPane().add(jtp);
jtp.add(e1);
jtp.add(e2);
jtp.addTab("Example 1", e1);
jtp.addTab("Example 2", e2);
setResizable(false);
pack();
setTitle("NLTP");
setLocationRelativeTo(null);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
JFrame frame = new Frame();
frame.setVisible(true);
}
});
}
}
例1
import javax.swing.*;
import java.awt.*;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.geom.AffineTransform;
/**
* Created by griffin on 12/7/2015.
*/
public class Example1 extends JPanel implements Runnable {
private final int B_WIDTH = 640;
private final int B_HEIGHT = 480;
private int DELAY = 25;
private Thread thread;
Ship player = new Ship(320, 240);
public Example1() {
initScreen();
}
private void initScreen() {
JButton explanation = new JButton("Explanation");
explanation.setBounds(0, 0, 150, 30);
this.setLayout(null);
add(explanation);
addKeyListener(new keyInput());
setFocusable(true);
setBackground(Color.BLACK);
setPreferredSize(new Dimension(B_WIDTH, B_HEIGHT));
setDoubleBuffered(true);
}
@Override
public void addNotify() {
super.addNotify();
thread = new Thread(this);
thread.start();
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
draw(g);
}
public void draw(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g;
AffineTransform old = g2d.getTransform();
g2d.rotate(Math.toRadians(player.angle));
g2d.drawImage(player.ship, player.x, player.y, null);
g2d.setTransform(old);
Toolkit.getDefaultToolkit().sync();
}
public void cycle() {
player.y += player.vY;
}
@Override
public void run() {
long beforeTime, timeDiff, sleep;
beforeTime = System.currentTimeMillis();
while (true) {
cycle();
repaint();
timeDiff = System.currentTimeMillis() - beforeTime;
sleep = DELAY - timeDiff;
if (sleep < 0) {
sleep = 2;
}
try {
Thread.sleep(sleep);
} catch (InterruptedException e) {
System.out.println("Interrupted: " + e.getMessage());
}
beforeTime = System.currentTimeMillis();
}
}
public class keyInput extends KeyAdapter {
@Override
public void keyReleased(KeyEvent e) {
int key = e.getKeyCode();
if(key == KeyEvent.VK_W) {
}
}
@Override
public void keyTyped(KeyEvent e) {
}
@Override
public void keyPressed(KeyEvent e) {
int key = e.getKeyCode();
if (key == KeyEvent.VK_W) {
player.vY -= 1;
}
if(key == KeyEvent.VK_A) {
player.angle++;
}
if(key == KeyEvent.VK_D) {
player.angle--;
}
}
}
}
解决方法:
KeyListener因焦点相关问题而闻名.组件不仅需要可聚焦,而且在注册关键事件之前必须具有键盘焦点.这是一个问题,因为由于各种原因,您的组件很容易失去焦点.
解决方案是使用旨在帮助解决此问题的密钥绑定API.有关详细信息,请参见How to Use Key Bindings.
Swing使用被动渲染方法.也就是说,当API决定需要更新某些内容时,就会发生更新.有关详细信息,请参见Painting in AWT and Swing
你真正需要的是某种主动渲染方法,其中更新是在常规基础上进行的.这可以通过多种方式实现,最简单的方法是使用Swing Timer,因为更新UI(或UI所依赖的值)是安全的,而不存在引入竞争条件的风险.有关详细信息,请参见How to use Swing Timers
因此,这个例子基本上将输入抽象为四个基本动作,左/右和上/下旋转.代码并不关心这些输入是如何生成的,只是它们可以生成.
然后,它使用键绑定API来注册输入的操作.这一切都是通过一个Action类完成的,它只是将一个Input添加到一个Set,Timer在确定重新绘制UI之前用它来确定应该应用哪些动作.
通过使用AffineTransform完成旋转.首先,我们将原点转换为精灵当前的x / y位置,然后围绕精灵的中心旋转它.这减少了很多与旋转物相关的复杂性/问题(我简单)
AffineTransform at = AffineTransform.getTranslateInstance(xPos, yPos);
at.rotate(Math.toRadians(angle), sprite.getWidth() / 2, sprite.getHeight() / 2);
g2d.setTransform(at);
g2d.drawImage(sprite, 0, 0, this);
请注意,图形上下文是共享资源,在进行这些类型的更改之前,您需要复制它(并在完成后处理它)
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.HashSet;
import java.util.Set;
import javax.imageio.ImageIO;
import javax.swing.AbstractAction;
import javax.swing.ActionMap;
import javax.swing.InputMap;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.KeyStroke;
import javax.swing.Timer;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class FlyingPoniesWithGuns {
public static void main(String[] args) {
new FlyingPoniesWithGuns();
}
public FlyingPoniesWithGuns() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
} catch (IOException ex) {
ex.printStackTrace();
}
}
});
}
public enum Input {
ROTATE_LEFT,
ROTATE_RIGHT,
UP,
DOWN
}
public class TestPane extends JPanel {
private BufferedImage sprite;
private double angle;
private int xPos, yPos;
private double xDelta, yDelta;
private Set<Input> inputs;
public TestPane() throws IOException {
inputs = new HashSet<>(25);
sprite = ImageIO.read(getClass().getResource("/Pony.png"));
xPos = (400 - sprite.getWidth()) / 2;
yPos = (400 - sprite.getHeight()) / 2;
addKeyBinding("rotate-left", KeyEvent.VK_A, Input.ROTATE_LEFT);
addKeyBinding("rotate-right", KeyEvent.VK_D, Input.ROTATE_RIGHT);
Timer timer = new Timer(40, new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
if (inputs.contains(Input.ROTATE_LEFT)) {
angle -= 5;
} else if (inputs.contains(Input.ROTATE_RIGHT)) {
angle += 5;
}
repaint();
}
});
timer.start();
}
@Override
public Dimension getPreferredSize() {
return new Dimension(400, 400);
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
g2d.setRenderingHint(RenderingHints.KEY_ALPHA_INTERPOLATION, RenderingHints.VALUE_ALPHA_INTERPOLATION_QUALITY);
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
g2d.setRenderingHint(RenderingHints.KEY_COLOR_RENDERING, RenderingHints.VALUE_COLOR_RENDER_QUALITY);
g2d.setRenderingHint(RenderingHints.KEY_DITHERING, RenderingHints.VALUE_DITHER_ENABLE);
g2d.setRenderingHint(RenderingHints.KEY_FRACTIONALMETRICS, RenderingHints.VALUE_FRACTIONALMETRICS_ON);
g2d.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR);
g2d.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
g2d.setRenderingHint(RenderingHints.KEY_STROKE_CONTROL, RenderingHints.VALUE_STROKE_PURE);
AffineTransform at = AffineTransform.getTranslateInstance(xPos, yPos);
at.rotate(Math.toRadians(angle), sprite.getWidth() / 2, sprite.getHeight() / 2);
g2d.setTransform(at);
g2d.drawImage(sprite, 0, 0, this);
g2d.dispose();
}
protected void addKeyBinding(String name, int keyCode, Input input) {
InputMap inputMap = getInputMap(WHEN_IN_FOCUSED_WINDOW);
ActionMap actionMap = getActionMap();
inputMap.put(KeyStroke.getKeyStroke(keyCode, 0, false), name + ".pressed");
actionMap.put(name + ".pressed", new InputAction(input, true));
inputMap.put(KeyStroke.getKeyStroke(keyCode, 0, true), name + ".released");
actionMap.put(name + ".released", new InputAction(input, false));
}
protected class InputAction extends AbstractAction {
private Input input;
private boolean pressed;
public InputAction(Input input, boolean pressed) {
this.input = input;
this.pressed = pressed;
}
@Override
public void actionPerformed(ActionEvent e) {
if (pressed) {
inputs.add(input);
} else {
inputs.remove(input);
}
}
}
}
}
运动怎么样？您可以查看How do I make an entity move in a direction?和How can I move a sprite in the direction it is facing?,了解有关如何实现这一目标的更多想法