import java.awt.*;
import java.applet.*;
import java.awt.event.*;
public class MouseEvents extends Applet implements MouseListener, MouseMotionListener
{
String msg = ""; // I am not implementing those methods which
int mouseX = 0, mouseY = 0; // are not related to my question
public void init()
{
addMouseListener(this);
addMouseMotionListener(this);
}
public void mouseEntered(MouseEvent me)
{
mouseX = 0;
mouseY = 10;
msg = "Mouse Entered";
repaint();
}
public void mouseMoved(MouseEvent me)
{
mouseX = me.getX();
mouseY = me.getY();
showStatus("Moving mouse at "+mouseX+", "+mouseY);
}
public void paint(Graphics g)
{
g.drawString(msg, mouseX, mouseY);
}
}
我的小程序窗口的坐标:
Upper left corner - (0, 0)
Lower left corner - (0, 199)
Upper right corner - (349, 0)
Lower right corner - (349, 199)
我的期望:
当鼠标进入小程序窗口时,应在坐标
处显示消息(0, 10)
"Mouse Entered"
当鼠标移动时,状态窗口中应显示消息
“Moving mouse at mouseX, mouseY”
。其中mouseX
和mouseY
为鼠标当前坐标
实际发生了什么:
消息 “鼠标进入”
没有显示在坐标 (0, 10)
处,而是显示在鼠标进入的初始坐标处小程序窗口***
例如,鼠标从左下角
和右下角
之间进入小程序窗口,比如说(187, 199)
,然后消息 "Mouse Entered"
不是显示在 (0, 10)
,而是显示在 (187, 199)
/p>
我的问题
尽管在 mouseEntered()
中指定了 mouseX = 0
和 mouseY = 10
,为什么消息 “Mouse Entered “
显示在鼠标进入小程序窗口的坐标处,而不是坐标 (0, 10)
处?
最佳答案
当您将鼠标移到查看 Pane 上时,查看 Pane 会经常重绘。
您正在此处覆盖 mouseX
和 mouseY
的值:
public void mouseMoved(MouseEvent me)
{
mouseX = me.getX();
mouseY = me.getY();
showStatus("Moving mouse at "+mouseX+", "+mouseY);
}
这会导致在您移动鼠标时在这些坐标处进行重绘。如果您希望 mouseEntered
不移动,您可以使用局部变量,例如
public void mouseMoved(MouseEvent me)
{
int currentMouseX = me.getX();
int currentMouseY = me.getY();
showStatus("Moving mouse at "+currentMouseX+", "+currentMouseY);
}
关于java - mouseEntered() 和 mouseMoved() 之间的混淆,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/31391869/