如何在jlist中添加图像

Question

嗨我已经创建了aj列表,我想在该文本中的任何文本之前添加图像我怎么能这样做我试过但我无法实现我的目标我想在列表元素"Barmer"之前添加图像.

    public class ListDemo extends JPanel
                          implements ListSelectionListener {
        private JList list;
        private DefaultListModel listModel;


        public ListDemo() {
            super(new BorderLayout());

            listModel = new DefaultListModel();
            listModel.addElement("Barmer");
           //Create the list and put it in a scroll pane.
            list = new JList(listModel);
            list.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
            list.setSelectedIndex(0);
            list.addListSelectionListener(this);
            list.setVisibleRowCount(5);
            list.setBackground(new java.awt.Color(0,191,255));;
           list.setFont(new Font("Arial",Font.BOLD,35));
            list.setForeground( Color.white );
            list.setFixedCellHeight(60);
    list.setFixedCellWidth(50);
    list.setBorder(new EmptyBorder(10,20, 20, 20));


            JScrollPane listScrollPane = new JScrollPane(list);
            add(listScrollPane, BorderLayout.CENTER);

        }
         public void valueChanged(ListSelectionEvent e) {

        }

        private static void createAndShowGUI() {
            //Create and set up the window.
            JFrame frame = new JFrame("ListDemo");
            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

            //Create and set up the content pane.
            JComponent newContentPane = new ListDemo();
            newContentPane.setOpaque(true); //content panes must be opaque
            frame.setContentPane(newContentPane);
           frame.setExtendedState(JFrame.MAXIMIZED_BOTH); 
    frame.setUndecorated(true);

            //Display the window.
            frame.pack();
            frame.setVisible(true);
        }



          public static void main(String[] args) {

                    createAndShowGUI();

        }
    }

我该怎么做才能帮到我？

提前致谢

Answer 1

你想看起来像一个自定义ListCellRenderer.您可以查看Provding a Custom Renderer for JComboBox.对于a来说也一样JList.对于简单的场景,本教程过于复杂.如果你只想要基本的功能,那么你可以扩展JLabel并implements ListCellRender实现一些不必要的东西.

您可以改为extends或创建一个匿名DefaultListCellRender,只需获取JLabel渲染组件并添加到它,如设置Font和ImageIcon.像这样的东西

public class MarioListRenderer extends DefaultListCellRenderer {

    Font font = new Font("helvitica", Font.BOLD, 24);

    @Override
    public Component getListCellRendererComponent(
            JList list, Object value, int index,
            boolean isSelected, boolean cellHasFocus) {

        JLabel label = (JLabel) super.getListCellRendererComponent(
                list, value, index, isSelected, cellHasFocus);
        label.setIcon(imageMap.get((String) value));
        label.setHorizontalTextPosition(JLabel.RIGHT);
        label.setFont(font);
        return label;
    }
}

会发生什么是每个单元格使用此渲染器并调用该getListCellRendererComponent方法.在value你看到传递给方法是在每个单元格的值,在我的情况,在列表中的角色的名字之一.然后我将其映射到相应的ImageIcon并Icon在JLabel渲染器组件上设置.

import java.awt.Component;
import java.awt.Dimension;
import java.awt.Font;
import java.util.HashMap;
import java.util.Map;
import javax.swing.DefaultListCellRenderer;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JScrollPane;
import javax.swing.SwingUtilities;

public class MarioList {

    private final Map<String, ImageIcon> imageMap;

    public MarioList() {
        String[] nameList = {"Mario", "Luigi", "Bowser", "Koopa", "Princess"};
        imageMap = createImageMap(nameList);
        JList list = new JList(nameList);
        list.setCellRenderer(new MarioListRenderer());

        JScrollPane scroll = new JScrollPane(list);
        scroll.setPreferredSize(new Dimension(300, 400));

        JFrame frame = new JFrame();
        frame.add(scroll);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }

    public class MarioListRenderer extends DefaultListCellRenderer {

        Font font = new Font("helvitica", Font.BOLD, 24);

        @Override
        public Component getListCellRendererComponent(
                JList list, Object value, int index,
                boolean isSelected, boolean cellHasFocus) {

            JLabel label = (JLabel) super.getListCellRendererComponent(
                    list, value, index, isSelected, cellHasFocus);
            label.setIcon(imageMap.get((String) value));
            label.setHorizontalTextPosition(JLabel.RIGHT);
            label.setFont(font);
            return label;
        }
    }

    private Map<String, ImageIcon> createImageMap(String[] list) {
        Map<String, ImageIcon> map = new HashMap<>();
        for (String s : list) {
            map.put(s, new ImageIcon(
                    getClass().getResource("/marioscaled/" + s + ".png")));
        }
        return map;
    }

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

边注

• AndrewThompson对于首先检查教程是正确的.您可以轻松找到一个示例实现,然后尝试一下.Swing教程可以在这里找到.在使用Swing组件下查看如何使用不同的组件.

• Swing应用程序应该在Event Dispatch Thread(EDT)上运行.您可以通过包装你这样做creatAndShowGui()的SwinUtilities.invokeLater....在初始线程中查看更多信息

更新与互联网图像.

新规范

import java.awt.Component;
import java.awt.Dimension;
import java.awt.Font;
import java.net.URL;
import java.util.HashMap;
import java.util.Map;
import javax.swing.DefaultListCellRenderer;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JScrollPane;
import javax.swing.SwingUtilities;

public class MarioList {

    private final Map<String, ImageIcon> imageMap;

    public MarioList() {
        String[] nameList = {"Mario", "Luigi", "Bowser", "Koopa", "Princess"};
        imageMap = createImageMap(nameList);
        JList list = new JList(nameList);
        list.setCellRenderer(new MarioListRenderer());

        JScrollPane scroll = new JScrollPane(list);
        scroll.setPreferredSize(new Dimension(300, 400));

        JFrame frame = new JFrame();
        frame.add(scroll);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }

    public class MarioListRenderer extends DefaultListCellRenderer {

        Font font = new Font("helvitica", Font.BOLD, 24);

        @Override
        public Component getListCellRendererComponent(
                JList list, Object value, int index,
                boolean isSelected, boolean cellHasFocus) {

            JLabel label = (JLabel) super.getListCellRendererComponent(
                    list, value, index, isSelected, cellHasFocus);
            label.setIcon(imageMap.get((String) value));
            label.setHorizontalTextPosition(JLabel.RIGHT);
            label.setFont(font);
            return label;
        }
    }

    private Map<String, ImageIcon> createImageMap(String[] list) {
        Map<String, ImageIcon> map = new HashMap<>();
        try {
            map.put("Mario", new ImageIcon(new URL("http://i.stack.imgur.com/NCsHu.png")));
            map.put("Luigi", new ImageIcon(new URL("http://i.stack.imgur.com/UvHN4.png")));
            map.put("Bowser", new ImageIcon(new URL("http://i.stack.imgur.com/s89ON.png")));
            map.put("Koopa", new ImageIcon(new URL("http://i.stack.imgur.com/QEK2o.png")));
            map.put("Princess", new ImageIcon(new URL("http://i.stack.imgur.com/f4T4l.png")));
        } catch (Exception ex) {
            ex.printStackTrace();
        }
        return map;
    }

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