下面是我在 JList 中显示图像的代码。我想编辑 JList 中显示的每个图像的描述。我不知道该怎么做并且需要帮助。谢谢...
import java.util.*;
import javax.imageio.ImageIO;
import javax.swing.*;
import javax.swing.border.Border;
import java.awt.*;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.Transferable;
import java.awt.datatransfer.UnsupportedFlavorException;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FilenameFilter;
import java.io.IOException;
import java.io.Serializable;
public class DesignPicture2 {
private static String imageName;
static ArrayList<String> imgName = new ArrayList<String>();
public static void main(String[] args) throws Exception {
DesignPicture2 mm = new DesignPicture2();
mm.getImageName("C:\\Images 2 display");
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
JFrame frame = new JFrame("Image panel");
frame.setSize(800, 500);
//frame.setLocationByPlatform(true);
frame.setLocation(600, 300);
JList imageList = createImageList();
frame.getContentPane().add(new JScrollPane(imageList));
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
private static JList createImageList() {
JList imageList = new JList(createModel("C:\\Images 2 display"));
imageList.setCellRenderer(new ImageCellRenderer());
imageList.setLayoutOrientation(JList.HORIZONTAL_WRAP);
imageList.setVisibleRowCount(0);
imageList.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
imageList.setFixedCellWidth(240);
imageList.setFixedCellHeight(120);
// imageList.setDragEnabled(false);
//imageList.setDropMode(DropMode.INSERT);
imageList.setTransferHandler(new ImageTransferHandler(imageList));
return imageList;
}
private static DefaultListModel createModel(String path) {
File folder = new File(path);
File[] listOfFiles = folder.listFiles();
DefaultListModel model = new DefaultListModel();
int count = 0;
for (int i = 0; i < listOfFiles.length - 1; i++) {
System.out.println("check path: " + listOfFiles[i]);
imageName = imgName.get(i).toString();
String name = listOfFiles[i].toString();
//load only JPEGS
if (name.endsWith("jpg")) {
try {
ImageIcon ii = new ImageIcon(ImageIO.read(listOfFiles[i]));
model.add(count, ii);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
return model;
}
static class ImageTransferHandler extends TransferHandler {
private static final DataFlavor DATA_FLAVOUR = new DataFlavor(ColorIcon.class, "Images");
private final JList previewList;
private boolean inDrag;
ImageTransferHandler(JList previewList) {
this.previewList = previewList;
}
public int getSourceActions(JComponent c) {
return TransferHandler.MOVE;
}
protected Transferable createTransferable(JComponent c) {
inDrag = true;
return new Transferable() {
public DataFlavor[] getTransferDataFlavors() {
return new DataFlavor[]{DATA_FLAVOUR};
}
public boolean isDataFlavorSupported(DataFlavor flavor) {
return flavor.equals(DATA_FLAVOUR);
}
public Object getTransferData(DataFlavor flavor) throws UnsupportedFlavorException, IOException {
return previewList.getSelectedValue();
}
};
}
public boolean canImport(TransferSupport support) {
if (!inDrag || !support.isDataFlavorSupported(DATA_FLAVOUR)) {
return false;
}
JList.DropLocation dl = (JList.DropLocation) support.getDropLocation();
if (dl.getIndex() == -1) {
return false;
} else {
return true;
}
}
public boolean importData(TransferSupport support) {
if (!canImport(support)) {
return false;
}
Transferable transferable = support.getTransferable();
try {
Object draggedImage = transferable.getTransferData(DATA_FLAVOUR);
JList.DropLocation dl = (JList.DropLocation) support.getDropLocation();
DefaultListModel model = (DefaultListModel) previewList.getModel();
int dropIndex = dl.getIndex();
if (model.indexOf(draggedImage) < dropIndex) {
dropIndex--;
}
model.removeElement(draggedImage);
model.add(dropIndex, draggedImage);
return true;
} catch (Exception e) {
e.printStackTrace();
return false;
}
}
protected void exportDone(JComponent source, Transferable data, int action) {
super.exportDone(source, data, action);
inDrag = false;
}
}
static class ImageCellRenderer extends JPanel implements ListCellRenderer {
int count = 0;
DefaultListCellRenderer defaultListCellRenderer = new DefaultListCellRenderer();
JLabel imageLabel = new JLabel();
JLabel descriptionLabel = new JLabel();
ImageCellRenderer() {
setLayout(new BorderLayout());
Border emptyBorder = BorderFactory.createEmptyBorder(5, 5, 5, 5);
imageLabel.setBorder(emptyBorder);
descriptionLabel.setBorder(emptyBorder);
add(imageLabel, BorderLayout.AFTER_LINE_ENDS);
add(descriptionLabel, BorderLayout.SOUTH);
// imageLabel.setText(imgName.get(0).toString());
}
public Component getListCellRendererComponent(JList list, Object value, int index, boolean isSelected, boolean cellHasFocus) {
defaultListCellRenderer.getListCellRendererComponent(list, value, index, isSelected, cellHasFocus);
setBorder(defaultListCellRenderer.getBorder());
setBackground(defaultListCellRenderer.getBackground());
imageLabel.setIcon((Icon) value);
if (count > imgName.size() - 1) {
count = 0;
} else {
descriptionLabel.setText(imgName.get(count).toString());
}
return this;
}
}
public void getImageName(String path) {
int c = 0;
final File dir = new File(path);
// array of supported extensions (use a List if you prefer)
final String[] EXTENSIONS = new String[]{
"jpg", "gif", "png", "bmp" // and other formats you need
// filter to identify images based on their extensions
};
final FilenameFilter IMAGE_FILTER = new FilenameFilter() {
@Override
public boolean accept(final File dir, final String name) {
for (final String ext : EXTENSIONS) {
if (name.endsWith("." + ext)) {
return (true);
}
}
return (false);
}
};
if (dir.isDirectory()) { // make sure it's a directory
for (final File f : dir.listFiles(IMAGE_FILTER)) {
BufferedImage img = null;
c++;
try {
img = ImageIO.read(f);
// you probably want something more involved here
// to display in your UI
System.out.println("image: " + f.getName());
imgName.add(f.getName().toString());
} catch (final IOException e) {
// handle errors here
System.out.println("Error!");
}
}
System.out.println("C: " + c);
} else {
System.out.println("Invalid Directory!");
}
}
static class ColorIcon implements Icon, Serializable {
private Color color;
ColorIcon(Color color) {
this.color = color;
}
public void paintIcon(Component c, Graphics g, int x, int y) {
g.setColor(color);
g.fillRect(x, y, getIconWidth(), getIconHeight());
}
public int getIconWidth() {
return 200;
}
public int getIconHeight() {
return 100;
}
public boolean equals(Object o) {
if (o == null || getClass() != o.getClass()) {
return false;
}
return color.equals(((ColorIcon) o).color);
}
}
}
当我运行上面的代码时，它以正确的方式显示图像，但是每个图像的描述是固定的，我不知道如何更改它。希望有人能帮助我。
最佳答案
我同意 trashgod(对他的建议 +1)，JTable 将是一个更简单的解决方案，原因如下...
JList 不支持可编辑性，因此您需要创建它...
因此，首先，我们需要某种 ListModel 来提供一些额外的功能，特别是在特定索引处设置值的能力...
import javax.swing.ListModel;
public interface MutableListModel<E> extends ListModel<E> {
public void setElementAt(E value, int index);
public boolean isCellEditable(int index);
}
接下来，我们需要某种编辑器，在这种情况下，遵循标准的 Swing API 约定，这需要某种基本接口(interface)
import java.awt.Component;
import javax.swing.CellEditor;
import javax.swing.JList;
public interface ListCellEditor<E> extends CellEditor {
public Component getListCellEditorComponent(
JList<E> list,
E value,
boolean isSelected,
int index);
public void applyEditorValue(E value);
}
现在，我们需要为自己创建一个自定义 JList，它能够实际执行编辑单元格值所需的所有功能...
诸如...
- 识别“开始编辑”事件
- 判断单元格是否可以编辑
- 管理编辑过程，准备和展示编辑器，了解编辑器何时停止或取消并适当清理...
- 在编辑过程中处理选择更改
- 处理组件焦点变化(我没有做过，因为这本身就很有趣......)
例如……
import java.awt.Component;
import java.awt.Rectangle;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import javax.swing.AbstractAction;
import javax.swing.ActionMap;
import javax.swing.InputMap;
import javax.swing.JList;
import javax.swing.KeyStroke;
import javax.swing.ListModel;
import javax.swing.event.CellEditorListener;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;
public class EditableList<E> extends JList<E> {
private ListCellEditor<E> editor;
private int editingCell = -1;
private Component editorComponent;
private CellEditorHandler handler;
public EditableList(MutableListModel<E> model) {
this();
setModel(model);
}
public EditableList() {
InputMap im = getInputMap(WHEN_ANCESTOR_OF_FOCUSED_COMPONENT);
im.put(KeyStroke.getKeyStroke(KeyEvent.VK_F2, 0), "editorCell");
ActionMap am = getActionMap();
am.put("editorCell", new AbstractAction() {
@Override
public void actionPerformed(ActionEvent e) {
System.out.println("Edit baby");
int cell = getSelectedIndex();
editCellAt(cell);
}
});
addListSelectionListener(new ListSelectionListener() {
@Override
public void valueChanged(ListSelectionEvent e) {
if (isEditing()) {
if (!stopCellEditing()) {
cancelCellEditing();
}
}
}
});
}
public boolean isEditing() {
return editorComponent != null;
}
public void cancelCellEditing() {
getEditor().cancelCellEditing();
}
public boolean stopCellEditing() {
return getEditor().stopCellEditing();
}
public CellEditorHandler getCellEditorHandler() {
if (handler == null) {
handler = new CellEditorHandler();
}
return handler;
}
public void setEditor(ListCellEditor<E> value) {
if (value != editor) {
ListCellEditor old = editor;
editor = value;
firePropertyChange("editor", old, editor);
}
}
public ListCellEditor<E> getEditor() {
return editor;
}
public boolean isCellEditable(int cell) {
boolean isEditable = false;
ListModel model = getModel();
if (model instanceof MutableListModel) {
MutableListModel mcm = (MutableListModel) model;
isEditable = mcm.isCellEditable(cell);
}
return isEditable;
}
protected void editCellAt(int index) {
if (isCellEditable(index)) {
ListCellEditor<E> editor = getEditor();
if (editor != null) {
Rectangle cellBounds = getCellBounds(index, index);
E value = getModel().getElementAt(index);
boolean selected = isSelectedIndex(index);
editingCell = index;
editor.addCellEditorListener(getCellEditorHandler());
editorComponent = editor.getListCellEditorComponent(this, value, selected, index);
editorComponent.setBounds(cellBounds);
ensureIndexIsVisible(index);
add(editorComponent);
revalidate();
}
}
}
public int getEditingCell() {
return editingCell;
}
protected void editingHasStopped(ListCellEditor editor) {
editingCell = -1;
if (editorComponent != null) {
remove(editorComponent);
}
if (editor != null) {
editor.removeCellEditorListener(getCellEditorHandler());
}
}
public class CellEditorHandler implements CellEditorListener {
@Override
public void editingStopped(ChangeEvent e) {
E value = getModel().getElementAt(getEditingCell());
getEditor().applyEditorValue(value);
((MutableListModel) getModel()).setElementAt(value, getEditingCell());
editingHasStopped((ListCellEditor)e.getSource());
}
@Override
public void editingCanceled(ChangeEvent e) {
editingHasStopped((ListCellEditor)e.getSource());
}
}
}
现在，完成所有这些后，您将需要更改构建程序的方式，而不是使用 List 和 ListModel 来管理描述和图像单独地，您可能应该将概念合并到一个单独的、可管理的对象中，例如...
public class ImagePreview {
private String name;
private ImageIcon image;
public ImagePreview(String name, ImageIcon image) {
this.name = name;
this.image = image;
}
public String getDescription() {
return name;
}
public ImageIcon getImage() {
return image;
}
protected void setDescription(String description) {
this.name = description;
}
}
即使您选择使用 JTable，您也会发现它更易于管理...
现在我们需要一些方法来渲染和编辑这些值，为此，我选择从一个可以显示图像和文本的基础组件开始......
public class ImagePreviewPane extends JPanel {
private JLabel imageLabel = new JLabel();
private JLabel descriptionLabel = new JLabel();
public ImagePreviewPane() {
setLayout(new BorderLayout());
Border emptyBorder = BorderFactory.createEmptyBorder(5, 5, 5, 5);
imageLabel.setBorder(emptyBorder);
descriptionLabel.setBorder(emptyBorder);
add(imageLabel, BorderLayout.CENTER);
add(descriptionLabel, BorderLayout.SOUTH);
}
protected JLabel getDescriptionLabel() {
return descriptionLabel;
}
protected JLabel getImageLabel() {
return imageLabel;
}
public void setImage(ImageIcon icon) {
imageLabel.setIcon(icon);
}
public void setDescription(String text) {
descriptionLabel.setText(text);
}
}
创建一个可以处理编辑的扩展版本...
public static class ImagePreviewEditorPane extends ImagePreviewPane {
private JTextField editor;
public ImagePreviewEditorPane() {
super();
editor = new JTextField();
remove(getDescriptionLabel());
add(editor, BorderLayout.SOUTH);
}
@Override
public void setDescription(String text) {
editor.setText(text);
}
public String getDescription() {
return editor.getText();
}
public void setImagePreview(ImagePreview preview) {
setImage(preview.getImage());
setDescription(preview.getDescription());
}
@Override
public void addNotify() {
super.addNotify();
editor.requestFocusInWindow();
}
}
这样做是为了让以后修改组件更容易......
接下来，一个ListCellRenderer
public class ImageCellRenderer extends ImagePreviewPane implements ListCellRenderer {
public ImageCellRenderer() {
}
@Override
public Component getListCellRendererComponent(JList list, Object value, int index, boolean isSelected, boolean cellHasFocus) {
Color bg = null;
Color fg = null;
JList.DropLocation dropLocation = list.getDropLocation();
if (dropLocation != null
&& !dropLocation.isInsert()
&& dropLocation.getIndex() == index) {
bg = DefaultLookup.getColor(this, getUI(), "List.dropCellBackground");
fg = DefaultLookup.getColor(this, getUI(), "List.dropCellForeground");
isSelected = true;
}
if (isSelected) {
setBackground(bg == null ? list.getSelectionBackground() : bg);
setForeground(fg == null ? list.getSelectionForeground() : fg);
} else {
setBackground(list.getBackground());
setForeground(list.getForeground());
}
if (value instanceof ImagePreview) {
ImagePreview ip = (ImagePreview) value;
setImage(ip.getImage());
setDescription(ip.getDescription());
} else {
setImage(null);
setDescription("??");
}
setEnabled(list.isEnabled());
setFont(list.getFont());
return this;
}
}
还有编辑器...
public class ImagePreviewListCellEditor extends AbstactListCellEditor<ImagePreview> {
private ImagePreviewEditorPane previewPane;
public ImagePreviewListCellEditor() {
previewPane = new ImagePreviewEditorPane();
InputMap im = previewPane.getInputMap(JComponent.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT);
im.put(KeyStroke.getKeyStroke(KeyEvent.VK_ENTER, 0), "accept");
im.put(KeyStroke.getKeyStroke(KeyEvent.VK_ESCAPE, 0), "cancel");
ActionMap am = previewPane.getActionMap();
am.put("accept", new AbstractAction() {
@Override
public void actionPerformed(ActionEvent e) {
stopCellEditing();
}
});
am.put("cancel", new AbstractAction() {
@Override
public void actionPerformed(ActionEvent e) {
cancelCellEditing();
}
});
}
public void applyEditorValue(ImagePreview preview) {
preview.setDescription(previewPane.getDescription());
}
@Override
public Component getListCellEditorComponent(JList<ImagePreview> list, ImagePreview value, boolean isSelected, int index) {
Color bg = null;
Color fg = null;
JList.DropLocation dropLocation = list.getDropLocation();
if (dropLocation != null
&& !dropLocation.isInsert()
&& dropLocation.getIndex() == index) {
bg = DefaultLookup.getColor(previewPane, previewPane.getUI(), "List.dropCellBackground");
fg = DefaultLookup.getColor(previewPane, previewPane.getUI(), "List.dropCellForeground");
isSelected = true;
}
if (isSelected) {
previewPane.setBackground(bg == null ? list.getSelectionBackground() : bg);
previewPane.setForeground(fg == null ? list.getSelectionForeground() : fg);
} else {
previewPane.setBackground(list.getBackground());
previewPane.setForeground(list.getForeground());
}
if (value instanceof ImagePreview) {
ImagePreview preview = (ImagePreview)value;
previewPane.setImagePreview(preview);
} else {
previewPane.setImagePreview(null);
}
return previewPane;
}
}
最后，把它放在一起......
public class DesignPicture2 {
public static void main(String[] args) throws Exception {
DesignPicture2 mm = new DesignPicture2();
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
JFrame frame = new JFrame("Image panel");
frame.setSize(800, 500);
frame.setLocation(600, 300);
JList imageList = createImageList();
frame.getContentPane().add(new JScrollPane(imageList));
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
private static JList createImageList() {
EditableList<ImagePreview> imageList = new EditableList(createModel("..."));
imageList.setEditor(new ImagePreviewListCellEditor());
imageList.setCellRenderer(new ImageCellRenderer());
imageList.setLayoutOrientation(JList.HORIZONTAL_WRAP);
imageList.setVisibleRowCount(0);
imageList.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
imageList.setFixedCellWidth(240);
imageList.setFixedCellHeight(120);
return imageList;
}
private static MutableListModel<ImagePreview> createModel(String path) {
File folder = new File(path);
File[] listOfFiles = folder.listFiles();
DefaultMutableListModel<ImagePreview> model = new DefaultMutableListModel<>();
int count = 0;
for (int i = 0; i < listOfFiles.length - 1; i++) {
System.out.println("check path: " + listOfFiles[i]);
String name = listOfFiles[i].toString();
if (name.endsWith("jpg")) {
try {
ImageIcon ii = new ImageIcon(ImageIO.read(listOfFiles[i]));
model.addElement(new ImagePreview(name, ii));
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
return model;
}
}
关于java - 如何更改JList java中的描述图像，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/23796471/