Java代碼優化

Question

我只是做了一個教程，如何使一個2D背景上的人物基本上像一個非常有限的平臺遊戲，沒有重力或任何東西，我已經遇到了一些滯後，我假設因爲它的方式按鍵/釋放的作品，但我想知道是否有任何方法來優化它，可能是因爲我沒有動畫它只是一個塊，但林不知道，就像如果我舉起，離開，然後我放手左邊，並按下權利，而所有的時間仍然舉起它只是上升，直到我放手，它滯後於左右等我將粘貼下面的代碼。謝謝！：

//@@@MAIN CLASS, NAMED CHECKERS ARBITRARILY 

import javax.swing.*; 

public class Checkers { 

public static void main(String[] args) { 
    JFrame frame = new JFrame("2D Game"); 

    frame.add(new Board()); 

    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
    frame.setSize(1200,326); 
    frame.setVisible(true); 
} 
} 


//@@@@@@@@@@@@@@@@@ 
//class called Dude this is my character(circle) 

import javax.swing.ImageIcon; 
import java.awt.Image; 
import java.awt.event.KeyEvent; 


public class Dude { 
int x, dx, y, dy; 
Image still; 

public Dude(){ 
    ImageIcon i = new ImageIcon("C:/still.png"); 
    still = i.getImage(); 
    x = 10; 
    y = 150; 
} 

public void move(){ 
    x = x + dx; 
    y = y + dy; 

} 

public int getX(){ 
    return x; 
} 

public int getY(){ 
    return y; 
} 

public Image getImage(){ 
    return still; 
} 

public void keyPressed(KeyEvent e){ 
    int key = e.getKeyCode(); 

    if (key == KeyEvent.VK_LEFT) 
     dx = -2; 

    if (key == KeyEvent.VK_RIGHT) 
     dx = 2; 

    if (key == KeyEvent.VK_UP) 
     dy = -2; 

    if (key == KeyEvent.VK_DOWN) 
     dy = 2; 

} 

    public void keyReleased(KeyEvent e){ 
    int key = e.getKeyCode(); 

    if (key == KeyEvent.VK_LEFT); 
     dx = 0; 

    if (key == KeyEvent.VK_RIGHT); 
     dx = 0; 

    if (key == KeyEvent.VK_UP) 
     dy = 0; 

    if (key == KeyEvent.VK_DOWN) 
     dy = 0; 

} 

} 


//@@@@@@@@@@@@@@@@@@@ 
//this is my board class (background) 



import java.awt.Graphics; 
import java.awt.Graphics2D; 
import java.awt.Image; 
import java.awt.event.ActionEvent; 
import java.awt.event.ActionListener; 
import java.awt.event.KeyAdapter; 
import java.awt.event.KeyEvent; 
import javax.swing.*; 

public class Board extends JPanel implements ActionListener{ 

Dude p; 
Image img; 
Timer time; 

public Board(){ 
    p = new Dude(); 
    addKeyListener(new AL()); 
    setFocusable(true); 
    ImageIcon i = new ImageIcon("C:/test.png"); 
    img = i.getImage(); 
    time = new Timer(5, this); 
    time.start(); 
} 
public void actionPerformed(ActionEvent e){ 
    p.move(); 
    repaint(); 
} 

public void paint(Graphics g){ 
    super.paint(g); 
      Graphics2D g2d = (Graphics2D) g; 

      g2d.drawImage(img, 0, 0, null); 
      g2d.drawImage(p.getImage(), p.getX(), p.getY(), null); 
} 

private class AL extends KeyAdapter{ 
    public void keyReleased(KeyEvent e){ 
     p.keyReleased(e); 
    } 
    public void keyPressed (KeyEvent e){ 
     p.keyPressed(e); 
    } 
} 

} 

Answer 1

這個工作對我來說：

package sof_6406645; 

import javax.swing.*; 

import java.awt.Graphics; 
import java.awt.Graphics2D; 
import java.awt.Image; 
import java.awt.Point; 
import java.awt.event.ActionEvent; 
import java.awt.event.ActionListener; 
import java.awt.event.KeyAdapter; 
import java.awt.event.KeyEvent; 

public class Checkers { 

    public static void main(String[] args) { 
     JFrame frame = new JFrame("2D Game"); 

     frame.add(new Board()); 

     frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
     frame.setSize(1200,326); 
     frame.setVisible(true); 
    } 
    public static class Board extends JPanel implements ActionListener { 

     final Image img; 
     Point p; 
     final boolean[] dynamics = new boolean[4]; 

     public Board() { 
      addKeyListener(new AL()); 
      setFocusable(true); 
      ImageIcon i = new ImageIcon("dude.png"); 
      img = i.getImage(); 
      p = new Point(0,0); 
      Timer timer = new Timer(5, this); 
      timer.start(); 
     } 
     public void actionPerformed(ActionEvent e){ 
      moveImage(); 
     } 
     public void moveImage(){ 
      int dx = 0; 
      int dy = 0; 
      if(dynamics[0]) dx = -2; 
      if(dynamics[1]) dy = -2; 
      if(dynamics[2]) dx = 2; 
      if(dynamics[3]) dy = 2; 
      p.move((int)p.getX() + dx, (int)p.getY() + dy); 
      repaint(); 
     } 

     public void paint(Graphics g){ 
      super.paint(g); 
      Graphics2D g2d = (Graphics2D) g; 
      g2d.drawImage(img, (int)p.getX(), (int)p.getY(), null); 
     } 

     private class AL extends KeyAdapter{ 
      public void keyReleased(KeyEvent e){ 
       updateDynamics(e, false); 
      } 
      public void keyPressed (KeyEvent e){ 
       updateDynamics(e, true); 
      } 
     } 
     final void updateDynamics(KeyEvent e, boolean v) { 
      int i = e.getKeyCode() - KeyEvent.VK_LEFT; 
      dynamics[i] = v; 
     } 
    } 
} 

[編輯]：

發了小修改，以糾正updateDynamics()的SIG和抵制的衝動，手動內聯（有效）將在兩個關鍵偵聽器方法中複製的1行代碼。該方法調用應該由JIT內聯。在moveImage()中的if語句的順序也可以被收緊以減半，但我很確定JVM會爲你處理這些事情。

說到if s，我最初並沒有改變你的互動模式，但我想如果你繼續按下兩個相反的移動鍵，Dude應該會停止冷，你不覺得嗎？

 public void moveImage(){ 
      int dx = 0; 
      int dy = 0; 
      if(dynamics[0]) dx -= 2; 
      if(dynamics[1]) dy -= 2; 
      if(dynamics[2]) dx += 2; 
      if(dynamics[3]) dy += 2; 
      p.move((int)p.getX() + dx, (int)p.getY() + dy); 
      repaint(); 
     }