JScrollPane中的透明JList都在一个类中 [英] Transparent JList in JScrollPane all in one class

问题描述

我有一个JFrame我已经淹没了背景：

I have a JFrame in which I have drown a background:

 class ImagePanel extends JComponent {
        private Image image;
        public ImagePanel(Image image) {
            this.image = image;
        }
        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            g.drawImage(image, 0, 0, this);
        }
    }

现在我必须列出一些对象，所以我添加了一个JScrollPane中的JList（不确定是否足够）。

Now I have to list some objects so I added a JList in a JScrollPane(not sure if that is adequate).

问题是：有没有办法制作项目区域的背景（JList和JScrollPane）透明，只显示项目列表？

我尝试了setOpaque的所有变体（false）;让viewPort没有得到它等...

I tried all variations of setOpaque(false); getting the viewPort not getting it and etc...

P.S。我看到了一个类似的问题，但是有一些类分离。我在一个类中有所有窗口组件。

P.S. I saw a similar question but there the were some kind of class separation.I have all the window components in one class.

推荐答案

你需要制作 JList ， JScrollPane 和 JScrollPane 的 JViewport 全透明，例如...

You need to make the JList, JScrollPane AND the JScrollPane's JViewport all transparent, for example...

list.setOpaque(false);
JScrollPane sp = new JScrollPane(list);
sp.setOpaque(false);
sp.getViewport().setOpaque(false);

哦，还有最后一招，你需要替换 JList 的单元格渲染器，如果未选中它将使其透明，例如

Oh, and one last trick, you need to replace the JList's cell renderer with one which will make it transparent when it's not selected, for example

public class TransparentListCellRenderer extends DefaultListCellRenderer {

    @Override
    public Component getListCellRendererComponent(JList<?> list, Object value, int index, boolean isSelected, boolean cellHasFocus) {
        super.getListCellRendererComponent(list, value, index, isSelected, cellHasFocus);
        setOpaque(isSelected);
        return this;
    }

}

package javaapplication1.pkg295;

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.DefaultListCellRenderer;
import javax.swing.DefaultListModel;
import javax.swing.JFrame;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class Test {

    public static void main(String[] args) {
        new Test();
    }

    public Test() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                    ex.printStackTrace();
                }

                JFrame frame = new JFrame("Testing");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setContentPane(new TestPane());

                DefaultListModel model = new DefaultListModel();
                model.addElement("Apple");
                model.addElement("Banana");
                model.addElement("Pear");
                model.addElement("Peach");
                model.addElement("Grap");
                JList list = new JList(model);
                list.setCellRenderer(new TransparentListCellRenderer());
                list.setOpaque(false);
                JScrollPane sp = new JScrollPane(list);
                sp.setOpaque(false);
                sp.getViewport().setOpaque(false);

                frame.add(sp);

                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public class TransparentListCellRenderer extends DefaultListCellRenderer {

        @Override
        public Component getListCellRendererComponent(JList<?> list, Object value, int index, boolean isSelected, boolean cellHasFocus) {
            super.getListCellRendererComponent(list, value, index, isSelected, cellHasFocus);
            setForeground(Color.WHITE);
            setOpaque(isSelected);
            return this;
        }

    }

    public class TestPane extends JPanel {

        private BufferedImage bgImg;

        public TestPane() {
            setLayout(new BorderLayout());
            try {
                bgImg = ImageIO.read(new File("C:\\Users\\shane\\Dropbox\\MegaTokyo\\Aqua\\200x200\\aria_manga_wallpaper-5541.jpg"));
            } catch (IOException ex) {
                ex.printStackTrace();
            }
        }

        @Override
        public Dimension getPreferredSize() {
            return bgImg == null ? new Dimension(200, 200) : new Dimension(bgImg.getWidth(), bgImg.getHeight());
        }

        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            if (bgImg != null) {
                Graphics2D g2d = (Graphics2D) g.create();
                int x = (getWidth() - bgImg.getWidth()) / 2;
                int y = (getHeight() - bgImg.getHeight()) / 2;
                g2d.drawImage(bgImg, x, y, this);
                g2d.dispose();
            }
        }

    }

}

这篇关于JScrollPane中的透明JList都在一个类中的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！