Java可选JLabel

Question

我制作了一个带有图库面板的GUI，其中显示了JLabels中保存的图像。我需要使JLabel可突出显示，然后在用户单击删除时将其删除。有办法还是应该改变我的做法？

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.File;

import javax.imageio.ImageIO;
import javax.swing.BoxLayout;
import javax.swing.DefaultListModel;
import javax.swing.ImageIcon;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.ListSelectionModel;
import javax.swing.border.LineBorder;
import javax.swing.border.TitledBorder;

public class GalleryPanel extends JPanel 
{

    private static final long serialVersionUID = 1L;
    private int currentImage;
    private JLabel[] images;
    private final int MAX_IMAGES = 12;
    private JScrollPane scrollPane;
    private JList<JLabel> imageGallery;
    private DefaultListModel<JLabel> listModel;
    private JPanel imageHolder;

public void init()
{   
    setLayout(new BorderLayout());

    imageHolder = new JPanel();
    imageHolder.setLayout(new BoxLayout(imageHolder, BoxLayout.PAGE_AXIS));
    imageHolder.setSize(getWidth(), getHeight());

    images = new JLabel[MAX_IMAGES];

    listModel = new DefaultListModel<JLabel>();
    listModel.addElement(new JLabel(new ImageIcon("Untitled.png")));


    imageGallery = new JList<JLabel>(listModel);
    imageGallery.setBackground(Color.GRAY);
    imageGallery.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
    imageGallery.setLayoutOrientation(JList.VERTICAL);
    imageGallery.setFixedCellHeight(50);
    imageGallery.setFixedCellWidth(100);

    scrollPane = new JScrollPane(imageHolder);
    scrollPane.setBackground(Color.RED);
    add(scrollPane, BorderLayout.CENTER);
}


public void addImageToGallery(File file)
{
    if ( currentImage <= images.length - 1)
    {   
        BufferedImage bufImage = null;

        try
        {
            bufImage = ImageIO.read(file);  //tries to load the image
        }
        catch (Exception e)
        {
            System.out.println("Unable to load file " + file.toString());
        }

        Image resizedImage = bufImage.getScaledInstance(bufImage.getWidth()/5, bufImage.getHeight()/5, Image.SCALE_SMOOTH);
        ImageIcon icon = new ImageIcon(resizedImage);

        images[currentImage] = new JLabel(icon, JLabel.CENTER);
        //images[currentImage].setSize(resized);
        //images[currentImage
        images[currentImage].setBorder(new TitledBorder(new LineBorder(Color.GRAY,5), file.toString()));


        imageHolder.add(images[currentImage]);

        revalidate();
        repaint();


        currentImage++;
    }
    else
    {
        throw new ArrayIndexOutOfBoundsException("The gallery is full");
    }
}


public final int getMaxImages()
{
    return MAX_IMAGES;
}


public Dimension getPreferredSize() 
{
    return new Dimension(300, 700);
}

}

Answer 1

所以你第一次打电话应该是tutorals

• How to use Lists
• Selecting items in a list
• Adding items to and removing items from a list

这将为您提供进行所需的基本信息。

根据您的可用代码，您不应该向JLabel添加ListModel，您不应该向数据模型添加组件，因为通常情况下，Swing组件有自己的概念他们将如何呈现它们。

在您的情况下，您真的很幸运，因为默认ListCellRenderer基于JLabel并会自动呈现Icon，例如

import javax.swing.DefaultListModel;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JList;
import javax.swing.JScrollPane;
import javax.swing.SwingUtilities;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;

public class Test {

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

    public Test() {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {

                DefaultListModel model = new DefaultListModel();
                model.addElement(new ImageIcon("mt01.jpg"));
                model.addElement(new ImageIcon("mt02.jpg"));
                model.addElement(new ImageIcon("mt03.jpg"));

                JList list = new JList(model);
                list.setVisibleRowCount(3);
                list.addListSelectionListener(new ListSelectionListener() {
                    @Override
                    public void valueChanged(ListSelectionEvent e) {
                        if (!e.getValueIsAdjusting()) {
                            System.out.println(list.getSelectedIndex());
                        }
                    }
                });

                JFrame frame = new JFrame("Test");
                frame.add(new JScrollPane(list));
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

}