mouseMoved事件不起作用

Question

我一直在努力工作這段代碼，就像當你將鼠標懸停在開始按鈕上時它應該將它的顏色更改爲灰色，但是每當我將鼠標懸停在它上面。沒有任何反應，有人可以告訴我爲什麼？我沒有得到任何錯誤，似乎我的mousemoved監聽器沒有被編譯器識別，對不起我的英文。我還沒有完成它尚未但這裏是代碼：

class Contents extends JFrame implements Runnable { 
    private Image dbi; 
    private Graphics dbg; 
    private boolean isStarted, isHovered; 
    private int x,y,xDir,yDir,bx,by,timer,life,my,mx,mhx,mhy; 
    private Rectangle startgame = new Rectangle(80,100,150,40); 
    Contents() 
    { 
    super(); 
    setVisible(true); 
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
    if(isStarted) 
    setSize(600,600); 
    else 
    {  
    setSize(300,300); 
    setBackground(Color.BLUE); 
    } 
    setLocationRelativeTo(null); 
    isStarted = false; 
    isHovered = false; 
    addMouseListener(new MouseAdapter() 
    { 
     public void mousePressed(MouseEvent e) 
     { 
      mx = e.getX(); 
      my = e.getY(); 
      if(mx > startgame.x && mx < startgame.x+startgame.width && 
       my > startgame.y && my < startgame.y+startgame.height) 
      { 
       isStarted = true; 
      } 
     } 
     public void mouseMoved(MouseEvent e) 
     { 
      mhx = e.getX(); 
      mhy = e.getY(); 
      if(mhx > startgame.x && mhx < startgame.x+startgame.width && 
       mhy > startgame.y && mhy < startgame.y+startgame.height) 
       isHovered = true; 
      else 
       isHovered = false; 

     } 
    }); 
    } 

    public void paint(Graphics g) 
    { 
     dbi = createImage(getWidth(), getHeight()); 
     dbg = dbi.getGraphics(); 
     draw(dbg); 
     g.drawImage(dbi,0,0,this); 
     repaint(); 
    } 
    public void draw(Graphics g) 
    { 
     if(!isStarted) 
     { 
       if(!isHovered) 
       g.setColor(Color.GRAY); 
       else 
       g.setColor(Color.GREEN); 
        g.fillRect(startgame.x, startgame.y, startgame.width, startgame.height); 
        g.setFont(new Font("Serif",Font.BOLD,24)); 
        g.setColor(Color.WHITE); 
        g.drawString("Start game", startgame.x+20, startgame.y+25); 
        g.drawString(String.format("hoverx: %d hovery: %d",mhx,mhy), 50,200); 
     } 
     else 
     { 
     } 
    } 
    public void run() 
    { 
    } } 

public class Game { 
    public static void main(String[] args) 
    { 
     Contents c = new Contents(); 
    } } 

Answer 1

只需使用Rectangle.contains(Point)檢查從MouseEvent點是Rectangle內。這裏是一個例子

import java.awt.Color; 
import java.awt.Dimension; 
import java.awt.Graphics; 
import java.awt.Graphics2D; 
import java.awt.Point; 
import java.awt.event.MouseEvent; 
import java.awt.event.MouseMotionAdapter; 
import java.awt.geom.Rectangle2D; 

import javax.swing.JFrame; 
import javax.swing.JPanel; 
import javax.swing.SwingUtilities; 

public class PaintedButton extends JPanel { 
    private static final Color HOVER_COLOR = Color.BLUE; 
    private static final Color NON_HOVER_COLOR = Color.GREEN; 
    private static final Rectangle2D RECTANGLE = new Rectangle2D.Double(50, 50, 
      200, 100); 

    private Color color = NON_HOVER_COLOR; 

    public PaintedButton() { 
     addMouseMotionListener(new MouseMotionAdapter() { 
      public void mouseMoved(MouseEvent e) { 
       Point p = e.getPoint(); 
       if (RECTANGLE.contains(p)) { 
        color = HOVER_COLOR; 
       } else { 
        color = NON_HOVER_COLOR; 
       } 
       repaint(); 
      } 
     }); 
    } 

    @Override 
    protected void paintComponent(Graphics g) { 
     super.paintComponent(g); 
     Graphics2D g2 = (Graphics2D) g; 
     g2.setPaint(color); 
     g2.fill(RECTANGLE); 

    } 

    @Override 
    public Dimension getPreferredSize() { 
     return new Dimension(300, 200); 
    } 

    public static void main(String[] args) { 
     SwingUtilities.invokeLater(new Runnable() { 
      public void run() { 
       JFrame frame = new JFrame(); 
       frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
       frame.add(new PaintedButton()); 
       frame.pack(); 
       frame.setLocationRelativeTo(null); 
       frame.setVisible(true); 
      } 
     }); 
    } 
}