更改鼠標事件的背景顏色

Question

我想在矩形外部單擊鼠標時更改背景顏色。 我只是不知道如何使用 MouseEvent。

import java.applet.*;
import java.awt.*;
import java.awt.event.*;

public class AnAppletWithMouseEvents extends Applet implements MouseListener {
public void init()
{
    addMouseListener(this);
}
public void paint(Graphics g)
{

    g.setColor(Color.green);
    g.drawRect(10, 30, 150, 150);
}
public void mouseClicked(MouseEvent e)
{
    String clickDesc;
    if (e.getClickCount() == 2)
        clickDesc = "double";
    else
        clickDesc = "single";

    System.out.println("Mouse was " + clickDesc + "-clicked at location (" +
        e.getX() + ", " + e.getY() + ")");

}
public void mouseEntered(MouseEvent e) {}
public void mouseExited(MouseEvent e) {}
public void mousePressed(MouseEvent e) {}
public void mouseReleased(MouseEvent e) {}
}

Answer 1

import java.applet.*;
import java.awt.*;
import java.awt.event.*;

public class AnAppletWithMouseEvents extends Applet implements MouseListener {
Color color = Color.green;
public void init()
{
    addMouseListener(this);
}
public void paint(Graphics g)
{

    g.setColor(this.color);
    g.drawRect(10, 30, 150, 150);
}
public void mouseClicked(MouseEvent e)
{
    this.color = color.red;
    this.repaint();

}
public void mouseEntered(MouseEvent e) {}
public void mouseExited(MouseEvent e) {}
public void mousePressed(MouseEvent e) {}
public void mouseReleased(MouseEvent e) {}
}

現在您需要計算點擊是否超出矩形邊界。

Answer 2

在mouseClicked方法中，您應該測試e.getX()和e.getY()在矩形之外，然后調用setBackground() ：

this.setBackground(Color.red);

矩形邊框將保持綠色（這是您想要的嗎？）

HTH