如果 MouseListener 已经在运行，如何触发事件方法

Question

在我的代码中我有：

具有普通 JPanel 的 JFrame，其中包含一些 JComponent 对象。 这些 JComponent 具有： - JTextFields 列表。 - 一个监听器，它在 mouseEntered 触发时突出显示其边框，并在 mouseExited 触发时隐藏它。 由于当光标越过嵌套在 JComponent 中的 jtextField 时也会触发 mouseExited 方法，因此 mouseExited 方法的实现会在隐藏边框之前检查事件的光标位置是否在 JComponentArea 之外：

问题是：

如果您缓慢移动鼠标，代码似乎可以正常工作，但如果您在组件之间快速移动鼠标，有时 JComponent 的边框不会隐藏。 我认为这可能是因为当光标越过嵌套的 textField 时触发了 mouseExited，然后当光标在 JComponent 之外时再次触发，但我不确定真正的问题是什么。 提前感谢您的任何提示或帮助！

守则：

已针对上述问题编写代码。这里是 Jcomponent 类（MyContainer）和包含 Main 的类（MyClass）：

import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.FlowLayout;

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;


public class MyClass {

    public static void main(String[] args)  {       
        SwingUtilities.invokeLater(new Runnable() {
            public void run(){   
                int i=0;
                //mainWindow
                    JFrame mainWindow = new JFrame("MyFrame");
                    mainWindow.setLayout(new BorderLayout());
                    mainWindow.setMinimumSize(new Dimension(300,300));

                    JPanel viewPort = new JPanel();
                    viewPort.setLayout(new FlowLayout(FlowLayout.LEFT));

                    MyContainer one = new MyContainer();
                    MyContainer two = new MyContainer();
                    MyContainer three = new MyContainer();

                    viewPort.add(one);
                    viewPort.add(two);
                    viewPort.add(three);
                    mainWindow.add(viewPort,BorderLayout.CENTER);
                    mainWindow.setVisible(true);
            }
        });
    }

}





import java.awt.Color;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;

import javax.swing.BorderFactory;
import javax.swing.JComponent;
import javax.swing.JTextField;

    @SuppressWarnings("serial")
    public  class MyContainer extends JComponent {
            JTextField text1 ;
            JTextField text2 ;
            JTextField text3 ;

            public MyContainer(){
                super.setLayout(new FlowLayout(FlowLayout.LEFT));
                super.setPreferredSize(new Dimension(200,50));
                super.setBorder(BorderFactory.createEmptyBorder(1, 1, 1, 1));
                super.setBackground(Color.green);

                text1 = new JTextField("LABEL_1");
                text1.setPreferredSize(new Dimension(60,30));
                text1.setEditable(false);
                this.add(text1);

                text2 = new JTextField("LABEL_2");
                text2.setPreferredSize(new Dimension(60,30));
                text2.setEditable(false);
                this.add(text2);

                text3 = new JTextField("LABEL_3");
                text3.setPreferredSize(new Dimension(60,30));
                text3.setEditable(false);
                this.add(text3);

                addListener();
            }

            private void addListener() {
                this.addMouseListener(new MouseListener() {
                    @Override
                    public void mouseEntered(MouseEvent e) {
                        MyContainer.this.setBorder(BorderFactory.createLineBorder(Color.BLUE));
                    }

                    @Override
                    public void mouseExited(MouseEvent e) {
                        Rectangle r = e.getComponent().getBounds();
                        Point p = e.getPoint();
                        if( p.x < 0 || p.y < 0 || p.x >= r.width || p.y >= r.height)
                            MyContainer.this.setBorder(BorderFactory.createEmptyBorder(1, 1, 1, 1));
                    }

                    @Override public void mouseClicked(MouseEvent e) { /*NOTHING*/ }
                    @Override public void mouseReleased(MouseEvent e) { /*NOTHING*/ }
                    @Override public void mousePressed(MouseEvent e) { /*NOTHING*/ }
                });         
            }
        }

Answer 1

这是使用MyContainer.this.dispatchEvent(SwingUtilities.convertMouseEvent(JTextField, e, MyContainer.this)); 的一种可能实现方式：

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

public class MyClass2 {
  public static void main(String[] args)  {
    SwingUtilities.invokeLater(new Runnable() {
      public void run() {
        int i = 0;
        //mainWindow
        JFrame mainWindow = new JFrame("MyFrame");
        mainWindow.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        mainWindow.setMinimumSize(new Dimension(300, 300));

        JPanel viewPort = new JPanel();
        viewPort.setLayout(new FlowLayout(FlowLayout.LEFT));

        MyContainer one = new MyContainer();
        MyContainer two = new MyContainer(true);
        viewPort.add(makeTitledPanel(one, "move it fast: NG?"));
        viewPort.add(makeTitledPanel(two, "move it fast: OK?"));
        mainWindow.add(viewPort, BorderLayout.CENTER);
        mainWindow.setVisible(true);
      }
    });
  }
  private static JComponent makeTitledPanel(JComponent c, String title) {
    JPanel p = new JPanel(new BorderLayout());
    p.setBorder(BorderFactory.createTitledBorder(title));
    p.add(c);
    return p;
  }
}

class MyContainer extends JComponent {
  JTextField text1 ;
  JTextField text2 ;
  JTextField text3 ;
  private final boolean flag;
  public MyContainer() {
    this(false);
  }
  public MyContainer(boolean flag) {
    super();
    this.flag = flag;

    super.setLayout(new FlowLayout(FlowLayout.LEFT));
    super.setPreferredSize(new Dimension(200, 50));
    super.setBorder(BorderFactory.createEmptyBorder(1, 1, 1, 1));
    super.setBackground(Color.green);

    text1 = new JTextField("LABEL_1");
    text2 = new JTextField("LABEL_2");
    text3 = new JTextField("LABEL_3");

    MouseListener l = new MouseEventConverter();
    for (JTextField f : Arrays.asList(text1, text2, text3)) {
      f.setPreferredSize(new Dimension(60, 30));
      f.setEditable(false);
      if (flag) {
        f.addMouseListener(l);
      }
      this.add(f);
    }
    this.addMouseListener(new MouseAdapter() {
      @Override
      public void mouseEntered(MouseEvent e) {
        MyContainer.this.setBorder(BorderFactory.createLineBorder(Color.BLUE));
      }
      @Override
      public void mouseExited(MouseEvent e) {
        Rectangle r = e.getComponent().getBounds();
        Point p = e.getPoint();
        if (p.x < 0 || p.y < 0 || p.x >= r.width || p.y >= r.height) {
          MyContainer.this.setBorder(BorderFactory.createEmptyBorder(1, 1, 1, 1));
        }
      }
    });
  }
}

class MouseEventConverter extends MouseAdapter {
  @Override public void mouseEntered(MouseEvent e) {
    dispatchMouseEvent(e);
  }
  @Override public void mouseExited(MouseEvent e) {
    dispatchMouseEvent(e);
  }
  private void dispatchMouseEvent(MouseEvent e) {
    Component c = e.getComponent();
    Component p = SwingUtilities.getUnwrappedParent(c);
    p.dispatchEvent(SwingUtilities.convertMouseEvent(c, e, p));
  }
}

Answer 2

我建议不要使用静态方法，尽管我不确定按照您的方式进行操作会产生什么实际影响。我会推荐

public void mouseEntered(MouseEvent e) {
    ((MyContainer) e.getSource()).setBorder(...)
}

// and so forth

此外，问题可能出在您的 mouseExited 方法上。而不是使用.getBounds()，我建议使用instanceof

if(e.getSource() instanceof MyContainer) {
    // do the stuff
} else {
    // do nothing
}

或者：

if(!(e.getSource() instanceof JTextField)) {
    // do the stuff
} else {
    // do nothing
}

else 语句甚至没有必要；我只是为了完整性而包含它。