为什么BufferedImage在JLabel中没有显示完整的图像？

Question

我从JFileChooser获取文件并通过阅读BufferedImage并放入JLabel来显示它们，但是有一个问题是我的图像没有完全显示在JLabel中。这是我的代码

public class ImagePreview
{
    JPanel PicHolder= new JPanel();
    public ImagePreview()
    {
        JButton GetImages = new JButton("Browse Images");
        GetImages.addMouseListener(new MouseAdapter() 
        {
            public void mouseClicked(MouseEvent evt) 
            {
                 CreatePreviews();
            };
        });
        PicHolder.add(GetImages);

        JFrame MainFrame = new JFrame("Image Preview");
        MainFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        MainFrame.getContentPane().add(PicHolder);
        MainFrame.pack();
        MainFrame.setVisible(true);
    }
    public void CreatePreviews()
    {
        JFileChooser chooser = new JFileChooser();
        chooser.setMultiSelectionEnabled(true);
        File[] selectedCarImages = chooser.getSelectedFiles();
        for(int a=0; a<selectedImages.length; a++)
        {
            try
            {
                BufferedImage myPicture = ImageIO.read(new File(selectedImages[a].getAbsolutePath()));
                JLabel picLabel = new JLabel(new ImageIcon(myPicture));
                PicHolder.add(picLabel);
            }
        }
    }

    public static void main(String[] args) 
    {
          java.awt.EventQueue.invokeLater(() -> {
                 new ImagePreview();
          });
    }
}

当我运行此代码时，它会显示用户选择的图像，但它们会自动显示在JLabel中并且不会完全显示。

这里有什么问题？为什么JLabel没有显示完整的图像？

Answer 1

您将所有组件和图片添加到具有默认FlowLayout的单个面板。相反，使用GridLayout作为图片标签，并将浏览按钮添加到框架的默认BorderLayout，如下所示。

经测试：

import java.awt.BorderLayout;
import java.awt.GridLayout;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;

public class ImagePreview {

    JFrame mainFrame = new JFrame("Image Preview");
    JPanel picHolder = new JPanel(new GridLayout(0, 1));

    public ImagePreview() {
        JButton getImages = new JButton("Browse Images");
        getImages.addMouseListener(new MouseAdapter() {
            @Override
            public void mouseClicked(MouseEvent evt) {
                CreatePreviews();
            }
        });
        mainFrame.add(getImages, BorderLayout.NORTH);
        mainFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        mainFrame.add(new JScrollPane(picHolder));
        mainFrame.pack();
        mainFrame.setLocationByPlatform(true);
        mainFrame.setVisible(true);
    }

    public void CreatePreviews() {
        JFileChooser chooser = new JFileChooser();
        chooser.setMultiSelectionEnabled(true);
        chooser.showOpenDialog(mainFrame);
        File[] selectedImages = chooser.getSelectedFiles();
        for (int a = 0; a < selectedImages.length; a++) {
            try {
                BufferedImage myPicture = ImageIO.read(new File(selectedImages[a].getAbsolutePath()));
                JLabel picLabel = new JLabel(new ImageIcon(myPicture));
                picHolder.add(picLabel);
                mainFrame.pack();
            } catch (IOException ex) {
                ex.printStackTrace();
            }
        }
    }

    public static void main(String[] args) {
        java.awt.EventQueue.invokeLater(() -> {
            new ImagePreview();
        });
    }
}