如何在jlist中添加圖像

Question

嗨我已經創建了aj列表，我想在該文本中的任何文本之前添加圖像我怎么能這樣做我試過但我無法實現我的目標我想在列表元素“Barmer”之前添加圖像。

    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();

        }
    }

我該怎么做才能幫到我？

提前致謝

Answer 1

您希望將其視為自定義ListCellRenderer 。 您可以查看為JComboBox 提供自定義渲染器 。 JList 。 對於簡單的場景，本教程過於復雜。 他們擴展了JLabel並implements ListCellRender ，如果你只想要基本的功能，那么你需要實現一些不必要的東西。

你可以改為extends或創建一個匿名的DefaultListCellRender ，只需獲取JLabel渲染組件並添加它，就像設置Font和ImageIcon 。 像這樣的東西

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;
    }
}

會發生什么是每個單元格使用此渲染器並調用getListCellRendererComponent方法。 該value你看到傳遞給方法是在每個單元格的值，在我的情況，在列表中的角色的名字之一。 然后，我將其映射到相應的ImageIcon並在JLabel渲染器組件上設置Icon 。

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();
            }
        });
    }
}

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邊注

• AndrewThompson對於首先檢查教程是正確的。 您可以輕松找到一個示例實現，然后嘗試一下。 Swing教程可以在這里找到。 在使用Swing組件下查看如何使用不同的組件。

• Swing應用程序應該在Event Dispatch Thread（EDT）上運行。 您可以通過將您的creatAndShowGui()包裝在creatAndShowGui()中來SwinUtilities.invokeLater... 。 在初始線程中查看更多信息

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新規范

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();
            }
        });
    }
}