侦听未在Swing中按下鼠标的组件上的鼠标释放事件 [英] Listen for mouse released event on component on which the mouse was not pressed in Swing

问题描述

是否可以在未按下组件的组件上监听鼠标释放事件?

Is it possible to listen for mouse released event on the component on which it was not pressed?

我知道，释放鼠标时，即使光标位于其他组件上方，也会在该组件的侦听器上为该组件的侦听器调用MouseListener.mouseReleased().

I know that when mouse is released MouseListener.mouseReleased()is invoked on the listeners for that component when mouse press originated even if the cursor is above other component.

如何通知组件或其侦听器鼠标在组件上方并被释放?

How to inform a component or its listeners that the mouse was over it and it was released?

推荐答案

如果将MouseListener添加到保存您感兴趣的组件的容器中，则可以找出在按下或拖动时鼠标悬停在哪个组件上.例如，在下面的代码中，我已将MouseAdapter(MouseListener，MouseMotionListener和MouseWheelListener的组合)添加到包含的JPanel中，并且在获取了鼠标事件在容器上的位置之后，我在容器上调用getComponentAt(Point p)来获取鼠标悬停的子组件:

If you add your MouseListener to the container that holds your components of interest, you can find out which component the mouse is over on press or drag. For instance in the code below, I've added my MouseAdapter (a combination MouseListener, MouseMotionListener, and MouseWheelListener) to the containing JPanel, and after getting the location of the mouse event on the container, I call getComponentAt(Point p) on my container to get the child component that the mouse was over:

import java.awt.Component;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;

import javax.swing.*;

@SuppressWarnings("serial")
public class TestMouseRelease extends JPanel {
   private String[] panelNames = { "Panel A", "Panel B" };

   public TestMouseRelease() {
      setLayout(new GridLayout(1, 0));
      MouseAdapter mAdapter = new MyMouseAdapter();

      addMouseListener(mAdapter);
      addMouseMotionListener(mAdapter);

      for (String panelName : panelNames) {
         JPanel panel = new JPanel();
         panel.setName(panelName);
         // panel.addMouseListener(mAdapter);
         // panel.addMouseMotionListener(mAdapter);
         panel.setBorder(BorderFactory.createTitledBorder(panelName));
         panel.add(Box.createRigidArea(new Dimension(300, 300)));
         add(panel);
      }
   }

   private class MyMouseAdapter extends MouseAdapter {
      @Override
      public void mousePressed(MouseEvent e) {
         displayInfo(e, "mousePressed");
      }

      @Override
      public void mouseReleased(MouseEvent e) {
         displayInfo(e, "mouseReleased");
      }

      @Override
      public void mouseDragged(MouseEvent e) {
         displayInfo(e, "mouseDragged");
      }

      private void displayInfo(MouseEvent e, String info) {
         JComponent comp = (JComponent) e.getSource();
         Component childComp = comp.getComponentAt(e.getPoint());
         if (childComp != null) {
            String name = childComp.getName();
            System.out.println(name + ": " + info);
         }
      }
   }

   private static void createAndShowGui() {
      JFrame frame = new JFrame("TestMouseRelease");
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.getContentPane().add(new TestMouseRelease());
      frame.pack();
      frame.setLocationRelativeTo(null);
      frame.setVisible(true);
   }

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

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