摆动鼠标听众被儿童组件拦截

Question

我有一个包含几个子组件的swing组件.如果鼠标位于任何组件之上,我想要做的是更改某些标签,如果鼠标移出所有组件,则将其更改为其他标签.我正试图找到一种更有效的方法来做到这一点.

目前,我对所有子组件都有鼠标监听器,它们看起来像:

class AMouseListener extends MouseAdapter {
    private boolean mouseOver;
    mouseEntered(MouseEvent e) { mouseOver = true; updateLabel(); }
    mouseExited(MouseEvent e) { mouseOver = false; updateLabel(); }

    void updateLabel() {
       String text = "not-over-any-components";
       // listeners are each of the listeners added to the child components
       for ( AMouseListener listener :listeners ) {
          if ( listener.mouseOver ) {
             text = "over-a-component";
             break;
          }
       }
    }
}

这是有效的,但我觉得应该有一个更好的方法来处理这个只通过处理父容器上的mouseEntered和mouseExited事件,但由于子组件拦截这些事件,我不知道如何去做(I不一定能控制子组件所以如果我愿意,我不能将鼠标事件转发给父事件.

Answer 1

例如

import java.awt.Component;
import java.awt.Dimension;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.*;

public class TestMouseListener {

    public static void main(String[] args) {
        final JComboBox combo = new JComboBox();
        combo.setEditable(true);
        for (int i = 0; i < 10; i++) {
            combo.addItem(i);
        }
        final JLabel tip = new JLabel();
        tip.setPreferredSize(new Dimension(300, 20));
        JPanel panel = new JPanel();
        panel.add(combo);
        panel.add(tip);
        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
        frame.add(panel);
        frame.pack();
        frame.setVisible(true);
        panel.addMouseListener(new MouseAdapter() {

            @Override
            public void mouseEntered(MouseEvent e) {
                tip.setText("Outside combobox");
            }

            @Override
            public void mouseExited(MouseEvent e) {
                Component c = SwingUtilities.getDeepestComponentAt(
                   e.getComponent(), e.getX(), e.getY());
                // doesn't work if you move your mouse into the combobox popup
                tip.setText(c != null && SwingUtilities.isDescendingFrom(
                   c, combo) ? "Inside combo box" : "Outside combobox");
            }
        });
    }

    private TestMouseListener() {
    }
}