只有在Java中按下鼠标时，如何使mouseEntered执行 [英] How to have mouseEntered execute only if mouse is pressed down in Java

问题描述

我想执行mouseEntered只有当鼠标当前被按下，基本上是：

I Want to execute the mouseEntered only IF the mouse is currently pressed down, basically this:

    @Override
    public void mouseEntered(MouseEvent e) {
       if(e.mouseDown()){
         //Do stuff
        }
    }

我可以这样做，还是需要一个鼠标移动监听器或什么？

can I do it like this, or do I need a mouse motion listener or what?

谢谢！

编辑：抱歉应该使这个更清楚，但是我需要鼠标按下在进入组件之前，它像按住鼠标并悬停在组件激活侦听器

Sorry should have made this more clear, but I need the mouse to be press down Before it enters the component, its like holding down the mouse and hovering over the component activates the listener

推荐答案

您可能需要评估MouseEvent API以查看可用的方法，因为我认为您将找到您的解决方案：

You might want to evaluate the MouseEvent API to see what methods are available, as I think that you will find your solution there:

  myComponent.addMouseListener(new MouseAdapter() {

     @Override
     public void mouseEntered(MouseEvent mEvt) {
        System.out.println("mouse entered");

        if (mEvt.getModifiers() == MouseEvent.BUTTON1_MASK) {
           System.out.println("Mouse dragging as entered");
        }

     }

  });

例如：

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class MouseEnteredPressed extends JPanel {
   private static final int SIDE = 500;

   public MouseEnteredPressed() {
      setLayout(new GridBagLayout());
      JLabel label = new JLabel("Hovercraft Rules The World!");
      label.setFont(label.getFont().deriveFont(Font.BOLD, 24));
      label.setBorder(BorderFactory.createLineBorder(Color.LIGHT_GRAY));
      add(label);

      label.addMouseListener(new MouseAdapter() {
         @Override
         public void mouseEntered(MouseEvent mEvt) {
            System.out.println("mouse entered");

            if (mEvt.getModifiers() == MouseEvent.BUTTON1_MASK) {
               System.out.println("Mouse dragging as entered");
            }
         }
      });

   }

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

   private static void createAndShowGui() {
      MouseEnteredPressed mainPanel = new MouseEnteredPressed();

      JFrame frame = new JFrame("MouseEnteredPressed");
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.getContentPane().add(mainPanel);
      frame.pack();
      frame.setLocationByPlatform(true);
      frame.setVisible(true);
   }

   public static void main(String[] args) {
      SwingUtilities.invokeLater(new Runnable() {
         public void run() {
            createAndShowGui();
         }
      });
   }
}

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