将一些图像从站点保存到ArrayList后我尝试创建一个jpanel，它将在带有滚动窗格的单独jpanel中显示所有这些图像，以便我可以向每个图像添加动作事件。然后，用户可以选择带有相关图片的jpanel，然后单击“复制”按钮将该图像保存到剪贴板。
以下代码可以正常添加一张图片：
picHolder = new JPanel();
picHolder.setSize(50,450);
picHolder.setBackground(Color.white);
Icon testicon = new ImageIcon(imageList.get(0));
JPanel test = new JPanel();
JLabel testLabel = new JLabel();
testLabel.setIcon(testicon);
test.add(testLabel);
picHolder.add(test);
然而，当我尝试使用以下循环在面板中创建面板时：
panelArray = new JPanel[imageList.size()];
labelArray = new JLabel[imageList.size()];
imageArray = new ImageIcon[imageList.size()];
for (int x=0; x>imageList.size(); x++) {
imageArray[x] = new ImageIcon(imageList.get(x));
panelArray[x] = new JPanel();
panelArray[x].setBackground(Color.red);
labelArray[x] = new JLabel();
labelArray[x].setIcon(imageArray[x]);
panelArray[x].setLayout(new FlowLayout());
panelArray[x].add(labelArray[x]);
picHolder.add(panelArray[x]);
picHolder.validate();
picHolder.repaint();
}
我只得到一个空白的屏幕。我试过移动各种元素然而我看不出我做错了什么。如果有人有任何建议或者可能是实现我的目标的另一种方式，我们将不胜感激。
修改
SSCCE
package scrollbartester;
import org.jsoup.Jsoup;
import org.jsoup.helper.Validate;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.jsoup.select.Elements;
import org.jsoup.select.Selector;
import java.net.*;
import javax.imageio.*;
import java.util.ArrayList;
import java.awt.*;
import java.awt.Event;
import javax.swing.*;
public class ScrollBarTester {
ArrayList<Image> imageList = new ArrayList<Image>() ;
URL url;
public ArrayList ripPics() {
String fullST = "http://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Dstripbooks&field-keywords=fish&x=0&y=0";
try {
Document doc = Jsoup.connect(fullST).timeout(10*1000).get();
Elements jpgs = doc.select("img[src$=.jpg]");
Element pictest = jpgs.get((jpgs.size()-1));
System.out.println(pictest);
for (int countPics = 0; countPics < jpgs.size(); countPics++) {
Element currentPic = jpgs.get(countPics);
String currentPicString = currentPic.toString();
System.out.println(currentPicString);
int startofAddress = currentPicString.indexOf("http:");
int endofAddress = (currentPicString.indexOf(".jpg") + 4);
String urlOfImage = currentPicString.substring(startofAddress, endofAddress);
url = new URL(urlOfImage);
Image currentImage = ImageIO.read(url);
imageList.add(currentImage);
}
}catch (MalformedURLException e) {
} catch (Exception e) {
e.printStackTrace();
}
return imageList;
}
public static void main(String[] args) {
PicRipper ripper = new PicRipper();
ArrayList<Image> imageList = ripper.ripPics();
System.out.println(imageList.size());
JScrollPane scrollPane;
JFrame main = new JFrame();
main.setSize(50, 500);
main.setDefaultCloseOperation(main.EXIT_ON_CLOSE);
JPanel picHolder = new JPanel();
picHolder.setSize(450,450);
picHolder.setBackground(Color.white);
//Icon testicon = new ImageIcon(imageList.get(0));
//JPanel test = new JPanel();
//JLabel testLabel = new JLabel();
//testLabel.setIcon(testicon);
//test.add(testLabel);
//picHolder.add(test);
JPanel [] panelArray = new JPanel[imageList.size()];
JLabel [] labelArray = new JLabel[imageList.size()];
ImageIcon [] imageArray = new ImageIcon[imageList.size()];
for (int x=0; x>imageList.size(); x++) {
imageArray[x] = new ImageIcon(imageList.get(x));
panelArray[x] = new JPanel();
panelArray[x].setBackground(Color.red);
labelArray[x] = new JLabel();
labelArray[x].setIcon(imageArray[x]);
panelArray[x].setLayout(new FlowLayout());
panelArray[x].add(labelArray[x]);
picHolder.add(panelArray[x]);
picHolder.validate();
picHolder.repaint();
}
scrollPane = new JScrollPane(picHolder);
main.getContentPane().add(BorderLayout.CENTER, scrollPane);
main.setVisible(true);
}
}
答案 0 :(得分：4)
例如，使用JList的SSCCE - 可以容纳ImageIcons：
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.Window;
import java.awt.image.BufferedImage;
import java.net.URL;
import java.util.concurrent.ExecutionException;
import javax.imageio.ImageIO;
import javax.swing.*;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;
public class PicStrip extends JPanel {
public static final String[] IMAGE_URLS = {
"http://upload.wikimedia.org/wikipedia/commons/6/63/Lagavulin_-_entrance.JPG",
"http://upload.wikimedia.org/wikipedia/commons/1/1d/Parliament-Ottawa_edit1.jpg",
"http://upload.wikimedia.org/wikipedia/commons/b/b0/100OLYMP1.jpg",
"http://upload.wikimedia.org/wikipedia/commons/1/17/Arpino_panorama.jpg",
"http://upload.wikimedia.org/wikipedia/commons/a/ad/Cegonha_alsaciana.jpg",
"http://upload.wikimedia.org/wikipedia/commons/1/18/Eau_transparente_naturelle.JPG",
"http://upload.wikimedia.org/wikipedia/commons/4/4d/FA-18F_Breaking_SoundBarrier.jpg",
"http://upload.wikimedia.org/wikipedia/commons/5/58/PuntadelEste.jpg",
"http://upload.wikimedia.org/wikipedia/commons/3/3c/Punta_Gorda_Belize-gm.jpg",
"http://upload.wikimedia.org/wikipedia/commons/6/64/Yungangshiku.JPG",
"http://upload.wikimedia.org/wikipedia/commons/e/e2/Wheel_of_Konark%2C_Orissa%2C_India.JPG",
"http://upload.wikimedia.org/wikipedia/commons/1/16/Muretto_a_secco.jpg",
"http://upload.wikimedia.org/wikipedia/commons/3/31/Mercedes_AMG_CLS_55_-_Demonstration_of_drifting_1a_1280x960.jpg",
"http://upload.wikimedia.org/wikipedia/commons/d/d3/Cascade_carieul_1280x960.jpg",
"http://upload.wikimedia.org/wikipedia/commons/1/17/Bobbahn_ep.jpg"
};
private ImageIcon[] icons = new ImageIcon[IMAGE_URLS.length];
private DefaultListModel iconListModel = new DefaultListModel();
private JList iconList = new JList(iconListModel);
private ImagePanel imagePanel = new ImagePanel();
public PicStrip() {
setLayout(new BorderLayout());
add(new JScrollPane(iconList), BorderLayout.LINE_START);
add(imagePanel, BorderLayout.CENTER);
new SwingWorker<Void, ImageIcon>() {
@Override
protected Void doInBackground() throws Exception {
for (String imageUrl : IMAGE_URLS) {
BufferedImage img = ImageIO.read(new URL(imageUrl));
img = ImageUtil.createScaledImage(img);
ImageIcon icon = new ImageIcon(img, imageUrl);
publish(icon);
}
return null;
}
protected void process(java.util.List<ImageIcon> chunks) {
for (ImageIcon icon : chunks) {
iconListModel.addElement(icon);
}
};
protected void done() {
Window win = SwingUtilities.getWindowAncestor(PicStrip.this);
win.pack();
};
}.execute();
iconList.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
iconList.addListSelectionListener(new ListSelectionListener() {
public void valueChanged(ListSelectionEvent e) {
ImageIcon icon = (ImageIcon)iconList.getSelectedValue();
final String imageUrl = icon.getDescription();
new SwingWorker<BufferedImage, Void>() {
protected BufferedImage doInBackground() throws Exception {
return ImageIO.read(new URL(imageUrl));
};
@Override
protected void done() {
try {
imagePanel.setImage(get());
} catch (InterruptedException e) {
e.printStackTrace();
} catch (ExecutionException e) {
e.printStackTrace();
}
}
}.execute();
}
});
}
private static void createAndShowGui() {
PicStrip mainPanel = new PicStrip();
JFrame frame = new JFrame("PicStrip");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
class ImagePanel extends JPanel {
private static final int PREF_W = (3 * 1280) / 4;
private static final int PREF_H = (3 * 960) / 4;
private BufferedImage img = null;
public void setImage(BufferedImage img) {
this.img = img;
repaint();
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (img == null) {
return;
}
Graphics2D g2 = (Graphics2D)g;
g2.setRenderingHint(RenderingHints.KEY_INTERPOLATION,
RenderingHints.VALUE_INTERPOLATION_BILINEAR);
g2.drawImage(img, 0, 0, PREF_W, PREF_H, null);
}
@Override
public Dimension getPreferredSize() {
return new Dimension(PREF_W, PREF_H);
}
}
class ImageUtil {
public static final int DEST_WIDTH = 100;
public static final int DEST_HEIGHT = 75;
public static final double ASPECT_RATIO = (double) DEST_WIDTH / DEST_HEIGHT;
public static BufferedImage createScaledImage(BufferedImage original) {
double origAspectRatio = (double) original.getWidth()
/ original.getHeight();
double scale = origAspectRatio > ASPECT_RATIO ?
(double) DEST_WIDTH / original.getWidth() :
(double) DEST_HEIGHT / original.getHeight();
int newW = (int) (original.getWidth() * scale);
int newH = (int) (original.getHeight() * scale);
BufferedImage img = new BufferedImage(DEST_WIDTH, DEST_HEIGHT,
BufferedImage.TYPE_INT_ARGB);
Graphics2D g2 = img.createGraphics();
g2.setRenderingHint(RenderingHints.KEY_INTERPOLATION,
RenderingHints.VALUE_INTERPOLATION_BILINEAR);
g2.drawImage(original, 0, 0, newW, newH, null);
g2.dispose();
return img;
}
}
编辑1
我已经检查了你的SSCCE - 感谢发布它，我发现的一个问题是错误的for循环。尝试更改此内容：
for (int x = 0; x > imageList.size(); x++) {
imageArray[x] = new ImageIcon(imageList.get(x));
//....
}
到此：
for (int x = 0; x < imageList.size(); x++) {
imageArray[x] = new ImageIcon(imageList.get(x));
//....
}
我不确定这是否是您实际程序中的错误，或者它只是SSCCE中的错误，但它很重要。