捕獲（捕獲）Java中的窗口中的鼠標光標

Question

我正在尋找一種方法來在窗口中捕獲或捕獲鼠標後進入該窗口，就像鼠標被困在虛擬機窗口中一樣，直到用戶按下CTRL + ALT + DEL或以其他方式釋放鼠標。我如何在Java中做到這一點？全屏顯示不是一種選擇。

編輯：

這是一些SSCCE爲雅。此代碼會將鼠標鎖定在窗口中。爲了脫身，你只需要在生成的框架內直接移動到關閉按鈕。如果您注意到鼠標嘗試離開它時會自動返回（0,0）。我需要知道的是如何讓它回到它退出的座標。我嘗試了getX（）和getY（）來代替（0,0），但機器人不會在那裏返回鼠標（我認爲響應時間會變慢）。我也讓機器人將鼠標移回crosshair.x和crosshair.y，但是如果用戶在正確的時刻點擊，這個（以及其他）仍然允許鼠標逃脫。有什麼想法嗎？

主類：

import java.awt.AWTException; 
import java.awt.Color; 
import java.awt.Cursor; 
import java.awt.event.MouseEvent; 
import java.awt.event.MouseListener; 
import java.awt.event.MouseMotionListener; 
import java.awt.Graphics; 
import java.awt.Image; 
import java.awt.image.BufferStrategy; 
import java.awt.image.MemoryImageSource; 
import java.awt.Point; 
import java.awt.Robot; 
import java.awt.Toolkit; 
import javax.swing.JFrame; 

public class Game extends JFrame implements MouseMotionListener, MouseListener{ 

    private int windowWidth = 640; 
    private int windowHeight = 480; 
     private Crosshair crosshair; 

    public static void main(String[] args) { 
     new Game(); 
    } 

    public Game() { 
     this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
     this.setSize(windowWidth, windowHeight); 
     this.setResizable(false); 
     this.setLocation(0,0); 
     this.setVisible(true); 

     this.createBufferStrategy(2); 
       addMouseMotionListener(this); 
       addMouseListener(this); 
     initGame(); 

     while(true) { 
      long start = System.currentTimeMillis(); 
      gameLoop(); 
      while(System.currentTimeMillis()-start < 5) { 
          //empty while loop 
      } 
     } 
    } 

    private void initGame() { 
      hideCursor(); 
      crosshair = new Crosshair (windowWidth/2, windowHeight/2); 
    } 

     private void gameLoop() { 
      //game logic 
      drawFrame(); 
     } 

     private void drawFrame() { 

      BufferStrategy bf = this.getBufferStrategy(); 
      Graphics g = (Graphics)bf.getDrawGraphics(); 
      try { 
       g = bf.getDrawGraphics(); 
       Color darkBlue = new Color(0x010040); 
       g.setColor(darkBlue); 
       g.fillRect(0, 0, windowWidth, windowHeight); 
       drawCrossHair(g); 
      } finally { 
       g.dispose(); 
      } 
      bf.show(); 
      Toolkit.getDefaultToolkit().sync(); 
     } 

     private void drawCrossHair(Graphics g){ 
      Color yellow = new Color (0xEDFF62); 
      g.setColor(yellow); 
      g.drawOval(crosshair.x, crosshair.y, 40, 40); 

      g.fillArc(crosshair.x + 10, crosshair.y + 21 , 20, 20, -45, -90); 
      g.fillArc(crosshair.x - 1, crosshair.y + 10, 20, 20, -135, -90); 
      g.fillArc(crosshair.x + 10, crosshair.y - 1, 20, 20, -225, -90); 
      g.fillArc(crosshair.x + 21, crosshair.y + 10, 20, 20, -315, -90); 
     } 

     @Override 
     public void mouseDragged(MouseEvent e) { 
     //empty method 
     } 

     @Override 
     public void mouseMoved(MouseEvent e) { 
     crosshair.x = e.getX(); 
     crosshair.y = e.getY(); 
     } 

     private void hideCursor() { 
      int[] pixels = new int[16 * 16]; 
      Image image = Toolkit.getDefaultToolkit().createImage(new MemoryImageSource(16, 16, pixels, 0, 16)); 
      Cursor transparentCursor = Toolkit.getDefaultToolkit().createCustomCursor(image, new Point(0, 0), "invisiblecursor"); 
      getContentPane().setCursor(transparentCursor); 
    } 

     public void mouseExited(MouseEvent e) { 
      System.out.println("Event: " + e); 
      try { 
       Robot robot = new Robot(); 
       robot.mouseMove(0, 0);// When I use (getX(),getY()) instead of (0,0) the robot will not move the mouse at all even though getX() and getY() are the coordinates I want the mouse to be moved to. Also the mouse can still escape, even when crosshair.x and crosshair.y are used as the coordinates. It seems that robot is too slow. 
      } 
      catch (AWTException ex) { 
       ex.printStackTrace(); 
      } 
     } 

     public void mouseEntered(MouseEvent e){ 
     } 

     public void mousePressed(MouseEvent e) { 
     } 

     public void mouseReleased(MouseEvent e) { 
     } 

     public void mouseClicked(MouseEvent e) { 
     } 
} 

另一類：

public class Crosshair{ 
     public int x; 
    public int y; 
    public Crosshair(int x, int y) { 
     this.x = x; 
     this.y = y; 
     } 
} 

Answer 1

我想你可以使用一個Global Event Listener爲偵聽鼠標進入該框架的事件。然後，在鼠標退出的事件中，我想您可以使用機器人在鼠標離開框架後重置鼠標的位置。

Answer 2

由於camickr提到，你可以使用機器人來做到這一點。它一般的東西，人們會建議反對，但這裏是一個不錯的機器人底漆，讓你開始：

http://www.developer.com/java/other/article.php/2212401/Introduction-to-the-Java-Robot-Class-in-Java.htm

Answer 3

好吧，我不假裝是一個遊戲開發者，但代碼中的鏈接介紹的是可怕的（從我可以告訴的）一個簡單的「乒乓球比賽」。我複製了代碼並使其運行，以便球彈跳。

在我的電腦上，CPU是50％，因爲無限的while循環浪費了CPU時間來提供球的運動動畫。使用一個睡眠時間爲5ms的線程的簡單改變，而不是使CPU持續5ms，導致CPU使用率下降到大約18％。

然後我改變了代碼在Swing面板上做球動畫。代碼更容易編寫，並且CPU使用率下降到1％，並且球動畫速度更快。

這是我的最終版本。您應該可以通過不將面板添加到框架，然後再次調用drawFrame（）方法來使用緩衝策略。

import java.awt.Color; 
import java.awt.Graphics; 
import java.awt.Toolkit; 
import java.awt.image.BufferStrategy; 

import javax.swing.*; 

public class Game3 extends JFrame { 

    /** 
    * @author Georgi Khomeriki 
    */ 

    private Ball ball; 

    // added this 
    private JPanel gamePanel; 

    private int windowWidth = 800; 
    private int windowHeight = 600; 


    public static void main(String[] args) { 
     new Game3(); 
    } 

    public Game3() { 
     this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
     this.setSize(windowWidth, windowHeight); 
     this.setResizable(false); 
     this.setLocation(100, 100); 
     this.setVisible(true); 

     this.createBufferStrategy(2); 

     initGame3(); 
/* 
     while(true) { 
      long start = System.currentTimeMillis(); 
      gameLoop(); 
      while(System.currentTimeMillis()-start < 5) { 
       //do nothing 
      } 
     } 
*/ 

     Thread thread = new Thread(new Runnable() 
     { 
      public void run() 
      { 
       while(true) 
       { 
        gameLoop(); 
        try { Thread.sleep(5); } 
        catch(Exception e) {} 
       } 
      } 
     }); 
     thread.start(); 

    } 

    private void initGame3() { 
     // all you're game variables should be initialized here 
     ball = new Ball(windowWidth/2, windowHeight/2, 5, 5); 

     // added these lines 

     gamePanel = new GamePanel(); 
     gamePanel.setBackground(Color.BLACK); 
     add(gamePanel); 
    } 

    private void gameLoop() { 
     // your game logic goes here 

// move the ball 
    ball.x = ball.x + ball.dx; 
    ball.y = ball.y + ball.dy; 

    // change the direction of the ball if it hits a wall 
    if(ball.x <= 0 || ball.x >= windowWidth-40) 
     ball.dx = -ball.dx; 
    if(ball.y <= 0 || ball.y >= windowHeight-40) 
     ball.dy = -ball.dy; 


     // changed to following to use Swing instead of buffer strategy 
//  drawFrame(); 
     gamePanel.repaint(); 
    } 

    private void drawFrame() { 
     // code for the drawing goes here 
     BufferStrategy bf = this.getBufferStrategy(); 
     Graphics g = null; 

     try { 
      g = bf.getDrawGraphics(); 

      // clear the back buffer (just draw a big black rectangle over it) 
      g.setColor(Color.BLACK); 
      g.fillRect(0, 0, windowWidth, windowHeight); 

drawBall(g); 


     } finally { 
      // It is best to dispose() a Graphics object when done with it. 
      g.dispose(); 
     } 

     // Shows the contents of the backbuffer on the screen. 
     bf.show(); 

     //Tell the System to do the Drawing now, otherwise it can take a few extra ms until 
     //Drawing is done which looks very jerky 
     Toolkit.getDefaultToolkit().sync(); 
    } 

    private void drawBall(Graphics g) { 

     g.setColor(Color.GREEN); 
     g.fillOval(ball.x, ball.y, 40, 40); 
    } 

    // added this 

    class GamePanel extends JPanel 
    { 
     protected void paintComponent(Graphics g) 
     { 
      super.paintComponent(g); 
      drawBall(g); 
     } 
    } 


    class Ball { 

     public int x; 
     public int y; 
     public int dx; 
     public int dy; 

     public Ball(int x, int y, int dx, int dy) { 
      this.x = x; 
      this.y = y; 
      this.dx = dx; 
      this.dy = dy; 
     } 
    } 



}