java - GlassPane 行为怪异

Question

我创建了一个 JPanel我在里面放了一个 JCheckBox和两个按钮:

选中复选框时，面板上方会显示一个透明色 (alpha = 100) 的玻璃 Pane ，并包含一个显示 String 的标签“正在加载...”，问题是当显示 glassPane 时复选框的位置发生变化:

当我改变框架的大小时，glassPane 变得不透明，所有在 glasspane 下可见的组件都变得不可见。

当我将尺寸更改为更小尺寸时，glassPane 的背景发生变化并变暗，标签字符串“Loading”变得模糊

这是我的代码，灵感来自关于 GlassPane 的 Oracle 教程 GlassPane Tutorial

package com.training.test;

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.FlowLayout;
import java.awt.Point;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;

import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;

class Training extends JFrame
{
    JCheckBox changeGlass;
    JButton button1, button2;

    public Training()
    {
        setBounds(100, 100, 400, 200);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setTitle("Test Glass Pane");
        getContentPane().setLayout(new FlowLayout(FlowLayout.LEFT));

        JPanel glass = (JPanel) getGlassPane();
        glass.setOpaque(true);
        glass.setBackground(new Color(120, 120, 120, 100));
        glass.setLayout(new BorderLayout());
        glass.add(new JLabel("Loading ..."));

        changeGlass = new JCheckBox("Show Glass Pane", false);

        changeGlass.addItemListener(new ItemListener()
        {
            public void itemStateChanged(ItemEvent e)
            {
                glass.setVisible(e.getStateChange() == ItemEvent.SELECTED);
            }
        });

        button1 = new JButton("Select");
        button2 = new JButton("Change");

        getContentPane().add(changeGlass);
        getContentPane().add(button1);
        getContentPane().add(button2);

        glass.addMouseListener(new MouseListener()
        {
            public void mouseReleased(MouseEvent e)
            {
                redispatchEvent(e, (JPanel) getContentPane(), glass);
            }

            public void mousePressed(MouseEvent e)
            {
                redispatchEvent(e, (JPanel) getContentPane(), glass);
            }

            public void mouseExited(MouseEvent e)
            {
                redispatchEvent(e, (JPanel) getContentPane(), glass);
            }

            public void mouseEntered(MouseEvent e)
            {
                redispatchEvent(e, (JPanel) getContentPane(), glass);
            }

            public void mouseClicked(MouseEvent e)
            {
                redispatchEvent(e, (JPanel) getContentPane(), glass);
            }
        });
    }

    public void redispatchEvent(MouseEvent e, JPanel panel, JPanel glass)
    {
        Point panelPoint = SwingUtilities.convertPoint(glass, e.getPoint(), panel);
        Component c = SwingUtilities.getDeepestComponentAt(panel, (int) panelPoint.getX(), (int) panelPoint.getY());

        Point componentPoint = SwingUtilities.convertPoint(panel, panelPoint, c);

        if (c != null && c.equals(changeGlass))
        {
            c.dispatchEvent(new MouseEvent(c, e.getID(), e.getWhen(), e.getModifiers(), (int) componentPoint.getX(), (int) componentPoint.getY(), e.getClickCount(), e
                    .isPopupTrigger()));
        }
        else
        {
            e.consume();
        }
    }
}

谁能纠正我做错了什么？

Answer 1

查看 Backgrounds With Transparency对于问题的可能原因和一些解决方案。基本上，因为您使用的是透明背景，所以您需要确保自己绘制玻璃 Pane 的背景。

所以我会创建一个自定义面板用作您的玻璃面板，这样您就可以管理背景的绘制。然后将此面板设置为框架的玻璃面板。