java – ActionListener调用阻止MouseClick事件

我有一个带有MenuItem“maddbound3”的窗口,其中包含以下ActionListener：

maddbound3.addActionListener
(
    new ActionListener()
    {
        public void actionPerformed(ActionEvent e)
        { 
            menu_addbound3();
        } 
    }
);

单击菜单时,此侦听器调用下面的menu_addbound3()：

void menu_addbound3()
{
    while(getEditMode() != EditMode.NONE)
    {
        System.out.println("!... " + getEditMode());

        synchronized(this)
        {
            try
            {
                wait();
            }
            catch(InterruptedException e)
            {
                e.printStackTrace();
            }
        }
    }
}

MouseClicked事件改变编辑模式的值并发出notifyAll(),以便while循环退出.但是,测试表明,当系统通过while循环运行时,单击鼠标时不会发生MouseClicked事件.

ActionListener是否阻止了MouseClicked事件？我该如何解决这个问题？

谢谢

解决方法:

在Swing事件线程上没有while(true),同样不在Swing事件线程上调用wait() – 你将冻结整个GUI,使其完全没有响应.您需要了解主Swing事件线程或“事件派发线程”负责所有Swing绘图和用户交互,因此如果您将其与长时间运行或冻结的代码绑定,则会锁定整个GUI.

相反,更改程序的状态 – 可能通过设置一个或两个变量,并使程序的行为依赖于此状态.如果您需要更具体的建议,请告诉我们您正在尝试实现的行为,我们或许可以为您提供更好的方法.

有关Swing事件线程的更多信息,请阅读：Lesson: Concurrency in Swing

编辑
你说：

When the user clicks the menu item I want to obtain information via a series of “discrete” mouse clicks from the window. Hence, on clicking the menu, the user would be prompted to “select a point in the window”. So, what I need is for my ActionListener function (menu_addbound3) to then wait for a mouse click. Hence the wait/notify setup. A mouse click changes the edit_mode and notifyAll() causes the wait in the while loop to exit which then causes the while loop to exit and I can then prompt for my next bit of information within the menu_addbound3 function, repeating this as as I need to.

感谢您的澄清,现在我可以肯定地告诉您,您做错了,您绝对不想使用while循环或等待或通知.有很多方法可以解决这个问题,一个可能是使用一些布尔值或枚举变量来给程序一个状态,然后根据状态改变它的行为.你可以在MouseListener中使用你的EditMode枚举让它知道它是活动的,然后你也可以给MouseListener类一个布尔变量windowPointSelected,设置为false,然后只在第一次点击后设置为true.

编辑2
例如：

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Point;
import java.awt.event.ActionEvent;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;

import javax.swing.*;

@SuppressWarnings("serial")
public class ProgState extends JPanel {
   private static final int PREF_W = 400;
   private static final int PREF_H = PREF_W;
   private static final Color EDIT_COLOR = Color.red;
   private EditMode editMode = EditMode.NONE;
   private boolean firstPointSelected = false;
   private JMenuBar jMenuBar = new JMenuBar();
   private JTextField firstPointField = new JTextField(15);
   private JTextField secondPointField = new JTextField(15);

   public ProgState() {
      add(firstPointField);
      add(secondPointField);

      JMenu menu = new JMenu("Menu");
      menu.add(new JMenuItem(new AbstractAction("Edit") {

         @Override
         public void actionPerformed(ActionEvent arg0) {
            setEditMode(EditMode.EDITING);
            setFirstPointSelected(false);
         }
      }));
      jMenuBar.add(menu);

      addMouseListener(new MouseAdapter() {

         @Override
         public void mousePressed(MouseEvent mEvt) {
            if (getEditMode() == EditMode.EDITING) {
               Point p = mEvt.getPoint();
               String pStr = String.format("[%d, %d]", p.x, p.y);
               if (!isFirstPointSelected()) {
                  firstPointField.setText(pStr);
                  setFirstPointSelected(true);
               } else {
                  secondPointField.setText(pStr);
                  setEditMode(EditMode.NONE);
               }
            }
         }

      });
   }

   public void setEditMode(EditMode editMode) {
      this.editMode = editMode;

      Color c = editMode == EditMode.NONE ? null : EDIT_COLOR;
      setBackground(c);
   }

   public EditMode getEditMode() {
      return editMode;
   }

   public void setFirstPointSelected(boolean firstPointSelected) {
      this.firstPointSelected = firstPointSelected;
   }

   public boolean isFirstPointSelected() {
      return firstPointSelected;
   }

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

   public JMenuBar getJMenuBar() {
      return jMenuBar;
   }

   private static void createAndShowGui() {
      ProgState progState = new ProgState();

      JFrame frame = new JFrame("EditMode");
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.getContentPane().add(progState);
      frame.setJMenuBar(progState.getJMenuBar());
      frame.pack();
      frame.setLocationRelativeTo(null);
      frame.setVisible(true);
   }

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

enum EditMode {
   NONE, EDITING
}

标签：actionlistener,mouseclick-event,java,swing
来源： https://codeday.me/bug/20190725/1538518.html