如何消除keyPress的延迟？
因此，我已经看到了一些与此相关的主题，并且需要一些有关如何专门修复它的帮助。按住某个键时，Java将读取第一次按键，然后稍有延迟，然后它将连续读取按键，直到您松开按键为止。
public void keyPressed(KeyEvent key) { int code = key.getKeyCode();
if (code == KeyEvent.VK_DOWN) {
//Do stuff
}
if (code == KeyEvent.VK_LEFT) {
//Do stuff
}
if (code == KeyEvent.VK_RIGHT) {
//Do stuff
}
if (code == KeyEvent.VK_UP) {
//Do stuff
}
}
那是我当前的代码。我听说要解决此问题，您可以创建一个计时器来快速检查按键是否按下，但是我不确定如何执行此操作。在这里或者如果有更好的解决方案，将不胜感激。
回答：
您问题的基本答案是，延迟不能是特定于操作系统的。
更长的答案是，您应该忽略各个事件本身，并通过使用适当的标志监视状态变化（在按下和释放之间）。
这意味着，当按下某个键时，您将设置一些标志，程序可以使用该标志来更改程序的状态，并在释放标志时将其重置。
这使事件与状态更改脱离关联，并为您提供了更大的灵活性，因为您的程序不在乎是什么原因导致状态更改，而只是在乎状态已更改并且应该对此做出反应。
这将需要您承担某种“循环”，其职责是监视此更改并做出相应的反应。在游戏中，这通常称为“游戏循环”，但也可以称为“主循环”。
正是这种“循环”责任来更新程序的状态并对其进行绘制。
下面是一个非常简单的示例，该示例使用键绑定API和javax.swing.Timer演示了基本概念
import com.sun.glass.events.KeyEvent;import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
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 MoveMe {
public static void main(String[] args) {
new MoveMe();
}
public MoveMe() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class MovementState {
public int xDirection;
public int yDirection;
}
public class TestPane extends JPanel {
private MovementState movementState;
private Rectangle box;
public TestPane() {
movementState = new MovementState();
InputMap im = getInputMap(WHEN_IN_FOCUSED_WINDOW);
ActionMap am = getActionMap();
im.put(KeyStroke.getKeyStroke(KeyEvent.VK_DOWN, 0, false), "down-pressed");
im.put(KeyStroke.getKeyStroke(KeyEvent.VK_DOWN, 0, true), "down-released");
im.put(KeyStroke.getKeyStroke(KeyEvent.VK_UP, 0, false), "up-pressed");
im.put(KeyStroke.getKeyStroke(KeyEvent.VK_UP, 0, true), "up-released");
im.put(KeyStroke.getKeyStroke(KeyEvent.VK_LEFT, 0, false), "left-pressed");
im.put(KeyStroke.getKeyStroke(KeyEvent.VK_LEFT, 0, true), "left-released");
im.put(KeyStroke.getKeyStroke(KeyEvent.VK_RIGHT, 0, false), "right-pressed");
im.put(KeyStroke.getKeyStroke(KeyEvent.VK_RIGHT, 0, true), "right-released");
am.put("down-pressed", new YDirectionAction(movementState, 2));
am.put("down-released", new YDirectionAction(movementState, 0));
am.put("up-pressed", new YDirectionAction(movementState, -2));
am.put("up-released", new YDirectionAction(movementState, 0));
am.put("left-pressed", new XDirectionAction(movementState, -2));
am.put("left-released", new XDirectionAction(movementState, 0));
am.put("right-pressed", new XDirectionAction(movementState, 2));
am.put("right-released", new XDirectionAction(movementState, 0));
box = new Rectangle(90, 90, 20, 20);
Timer timer = new Timer(40, new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
box.x += movementState.xDirection;
box.y += movementState.yDirection;
if (box.x < 0) {
box.x = 0;
} else if (box.x + box.width > getWidth()) {
box.x = getWidth() - box.width;
}
if (box.y < 0) {
box.y = 0;
} else if (box.y + box.height > getHeight()) {
box.y = getHeight() - box.height;
}
repaint();
}
});
timer.start();
}
@Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
g2d.setColor(Color.RED);
g2d.fill(box);
g2d.dispose();
}
}
public abstract class AbstractDirectionAction extends AbstractAction {
private final MovementState movementState;
private final int value;
public AbstractDirectionAction(MovementState movementState, int value) {
this.movementState = movementState;
this.value = value;
}
public MovementState getMovementState() {
return movementState;
}
public int getValue() {
return value;
}
}
public class YDirectionAction extends AbstractDirectionAction {
public YDirectionAction(MovementState movementState, int value) {
super(movementState, value);
}
@Override
public void actionPerformed(ActionEvent e) {
getMovementState().yDirection = getValue();
}
}
public class XDirectionAction extends AbstractDirectionAction {
public XDirectionAction(MovementState movementState, int value) {
super(movementState, value);
}
@Override
public void actionPerformed(ActionEvent e) {
getMovementState().xDirection = getValue();
}
}
}
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