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java – 拖放后移动组件
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内容图文
问题1：在删除图像后,如何在丢弃的面板内移动图像(使用鼠标指针). (图像的目的地,我想要在哪里释放鼠标.然后改变位置(使用鼠标会更好.或使用按钮 – 但使用鼠标更好)
问题2：如何在结束后更改位置？
p.s我想在这里图像到组件.
首先我拖放组件.然后使用鼠标指针更改位置(移动它).
这是代码：
import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.GridBagLayout;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.Transferable;
import java.awt.datatransfer.UnsupportedFlavorException;
import java.awt.dnd.DnDConstants;
import java.awt.dnd.DragGestureEvent;
import java.awt.dnd.DragGestureListener;
import java.awt.dnd.DragGestureRecognizer;
import java.awt.dnd.DragSource;
import java.awt.dnd.DragSourceDragEvent;
import java.awt.dnd.DragSourceDropEvent;
import java.awt.dnd.DragSourceEvent;
import java.awt.dnd.DragSourceListener;
import java.awt.dnd.DropTarget;
import java.awt.dnd.DropTargetDragEvent;
import java.awt.dnd.DropTargetDropEvent;
import java.awt.dnd.DropTargetEvent;
import java.awt.dnd.DropTargetListener;
import java.io.IOException;
import javax.swing.DefaultListModel;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class TestDnD {
public static void main(String[] args) {
new TestDnD();
}
public TestDnD() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException ex) {
} catch (InstantiationException ex) {
} catch (IllegalAccessException ex) {
} catch (UnsupportedLookAndFeelException ex) {
}
JFrame frame = new JFrame("Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
private JList list;
public TestPane() {
setLayout(new BorderLayout());
list = new JList();
DefaultListModel model = new DefaultListModel();
model.addElement(new User("Shaun"));
model.addElement(new User("Andy"));
model.addElement(new User("Luke"));
model.addElement(new User("Han"));
model.addElement(new User("Liea"));
model.addElement(new User("Yoda"));
list.setModel(model);
add(new JScrollPane(list), BorderLayout.WEST);
DragGestureRecognizer dgr = DragSource.getDefaultDragSource().createDefaultDragGestureRecognizer(
list,
DnDConstants.ACTION_COPY_OR_MOVE,
new DragGestureHandler(list));
JPanel panel = new JPanel(new GridBagLayout());
add(panel);
DropTarget dt = new DropTarget(
panel,
DnDConstants.ACTION_COPY_OR_MOVE,
new DropTargetHandler(panel),
true);
}
}
public static class User {
private String name;
public User(String name) {
this.name = name;
}
public String getName() {
return name;
}
@Override
public String toString() {
return name;
}
}
public static class UserTransferable implements Transferable {
public static final DataFlavor USER_DATA_FLAVOR = new DataFlavor(User.class, "User");
private User user;
public UserTransferable(User user) {
this.user = user;
}
@Override
public DataFlavor[] getTransferDataFlavors() {
return new DataFlavor[]{USER_DATA_FLAVOR};
}
@Override
public boolean isDataFlavorSupported(DataFlavor flavor) {
return USER_DATA_FLAVOR.equals(flavor);
}
@Override
public Object getTransferData(DataFlavor flavor) throws UnsupportedFlavorException, IOException {
Object value = null;
if (USER_DATA_FLAVOR.equals(flavor)) {
value = user;
} else {
throw new UnsupportedFlavorException(flavor);
}
return value;
}
}
protected class DragGestureHandler implements DragGestureListener {
private JList list;
public DragGestureHandler(JList list) {
this.list = list;
}
@Override
public void dragGestureRecognized(DragGestureEvent dge) {
Object selectedValue = list.getSelectedValue();
if (selectedValue instanceof User) {
User user = (User) selectedValue;
Transferable t = new UserTransferable(user);
DragSource ds = dge.getDragSource();
ds.startDrag(dge, null, t, new DragSourceHandler());
}
}
}
protected class DragSourceHandler implements DragSourceListener {
public void dragEnter(DragSourceDragEvent dsde) {
}
public void dragOver(DragSourceDragEvent dsde) {
}
public void dropActionChanged(DragSourceDragEvent dsde) {
}
public void dragExit(DragSourceEvent dse) {
}
public void dragDropEnd(DragSourceDropEvent dsde) {
System.out.println("Drag ended...");
}
}
protected class DropTargetHandler implements DropTargetListener {
private JPanel panel;
public DropTargetHandler(JPanel panel) {
this.panel = panel;
}
public void dragEnter(DropTargetDragEvent dtde) {
if (dtde.getTransferable().isDataFlavorSupported(UserTransferable.USER_DATA_FLAVOR)) {
System.out.println("Accept...");
dtde.acceptDrag(DnDConstants.ACTION_COPY_OR_MOVE);
} else {
System.out.println("Drag...");
dtde.rejectDrag();
}
}
public void dragOver(DropTargetDragEvent dtde) {
}
public void dropActionChanged(DropTargetDragEvent dtde) {
}
public void dragExit(DropTargetEvent dte) {
}
public void drop(DropTargetDropEvent dtde) {
System.out.println("Dropped...");
if (dtde.getTransferable().isDataFlavorSupported(UserTransferable.USER_DATA_FLAVOR)) {
Transferable t = dtde.getTransferable();
if (t.isDataFlavorSupported(UserTransferable.USER_DATA_FLAVOR)) {
try {
Object transferData = t.getTransferData(UserTransferable.USER_DATA_FLAVOR);
if (transferData instanceof User) {
User user = (User) transferData;
dtde.acceptDrop(DnDConstants.ACTION_COPY_OR_MOVE);
panel.add(new JLabel(user.getName()));
panel.revalidate();
panel.repaint();
} else {
dtde.rejectDrop();
}
} catch (UnsupportedFlavorException ex) {
ex.printStackTrace();
dtde.rejectDrop();
} catch (IOException ex) {
ex.printStackTrace();
dtde.rejectDrop();
}
} else {
dtde.rejectDrop();
}
}
}
}
}
解决方法:
这是在两个类似窗格之间拖动图像的实现.
如果您要放弃不允许组件移动的限制,那么您将不得不确保源和目标容器知道如何处理拖放(并呈现结果)
这花费了4个小时,所以在你敲定更新请求之前,请确保你已经努力理解代码并实现了自己的更改
该实现将Image包装在DragImage类中,该类维护有关图像在其容器内的位置的信息,这用于生成拖动图像…
import java.awt.AlphaComposite;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridLayout;
import java.awt.Image;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.Transferable;
import java.awt.datatransfer.UnsupportedFlavorException;
import java.awt.dnd.DnDConstants;
import java.awt.dnd.DragGestureEvent;
import java.awt.dnd.DragGestureListener;
import java.awt.dnd.DragGestureRecognizer;
import java.awt.dnd.DragSource;
import java.awt.dnd.DragSourceDragEvent;
import java.awt.dnd.DragSourceDropEvent;
import java.awt.dnd.DragSourceEvent;
import java.awt.dnd.DragSourceListener;
import java.awt.dnd.DropTarget;
import java.awt.dnd.DropTargetDragEvent;
import java.awt.dnd.DropTargetDropEvent;
import java.awt.dnd.DropTargetEvent;
import java.awt.dnd.DropTargetListener;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import javax.imageio.ImageIO;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.border.EmptyBorder;
import javax.swing.border.LineBorder;
public class TestDnD {
public static void main(String[] args) {
new TestDnD();
}
public TestDnD() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException ex) {
} catch (InstantiationException ex) {
} catch (IllegalAccessException ex) {
} catch (UnsupportedLookAndFeelException ex) {
}
JFrame frame = new JFrame("Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new GridLayout(0, 2, 10, 10));
((JComponent) frame.getContentPane()).setBorder(new EmptyBorder(10, 10, 10, 10));
BufferedImage img = ImageIO.read(new File("issue376.jpg"));
ImagePane imagePane = new ImagePane();
imagePane.addImage(img);
frame.add(imagePane);
frame.add(new ImagePane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
} catch (IOException ex) {
ex.printStackTrace();
System.exit(0);
}
}
});
}
public class ImagePane extends JPanel {
private List<DragImage> images;
private DragImages dropImages;
private Point dragPoint;
public ImagePane() {
setBorder(new LineBorder(Color.GRAY));
images = new ArrayList<>(25);
DragGestureRecognizer dgr = DragSource.getDefaultDragSource().createDefaultDragGestureRecognizer(
this,
DnDConstants.ACTION_COPY_OR_MOVE,
new DragGestureHandler(this));
DropTarget dt = new DropTarget(
this,
DnDConstants.ACTION_COPY_OR_MOVE,
new DropTargetHandler(this),
true);
}
@Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
public DragImage getImageAt(Point p) {
DragImage at = null;
for (DragImage di : images) {
if (di.contains(p)) {
at = di;
break;
}
}
return at;
}
protected boolean contains(Image image) {
boolean contains = false;
for (DragImage di : images) {
if (di.getImage() == image) {
contains = true;
break;
}
}
return contains;
}
public void addImage(Image image) {
if (image != null) {
if (!contains(image)) {
int x = (int) Math.round(Math.random() * getWidth());
int y = (int) Math.round(Math.random() * getHeight());
addImageAt(new Point(x, y), image);
}
}
}
public void addImageAt(Point p, Image image) {
if (p != null && image != null) {
if (!contains(image)) {
DragImage di = new DragImage(image, p);
images.add(di);
repaint();
}
}
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
for (DragImage di : images) {
g2d.drawImage(di.getImage(), di.getLocation().x, di.getLocation().y, this);
}
if (dropImages != null) {
g2d.setComposite(AlphaComposite.SrcOver.derive(0.5f));
Point offset = dropImages.getOffset();
for (DragImage di : dropImages.getImages()) {
Point pp = new Point(dragPoint);
pp.x -= offset.getX();
pp.y -= offset.getY();
g2d.drawImage(di.getImage(), pp.x, pp.y, this);
}
}
g2d.dispose();
}
public void removeImages(List list) {
if (list != null && list.size() > 0) {
for (Object obj : list) {
if (obj instanceof DragImage) {
removeImage((DragImage) obj);
}
}
}
}
public void removeImage(DragImage img) {
images.remove(img);
repaint();
}
protected void setDragImages(DragImages dragImages) {
this.dropImages = dragImages;
repaint();
}
public void addImagesAt(Point location, List images) {
if (images != null && images.size() > 0) {
for (Object obj : images) {
if (obj instanceof Image) {
Image img = (Image) obj;
addImageAt(location, img);
location.x += 10;
location.y += 10;
if (location.x >= getWidth()) {
location.x = 0;
}
if (location.y >= getHeight()) {
location.y = 0;
}
}
}
}
}
protected void addImages(DragImages dragImages) {
for (DragImage di : dragImages.getImages()) {
images.add(di);
}
repaint();
}
protected void addImagesAt(Point dropPoint, DragImages dragImages) {
Point offset = dragImages.getOffset();
for (DragImage di : dragImages.getImages()) {
Point p = di.getLocation();
p.x = dropPoint.x - offset.x;
p.y = dropPoint.y - offset.y;
images.add(di);
}
repaint();
}
protected void setDragPoint(Point location) {
dragPoint = location;
repaint();
}
}
public static class ImageTransferable implements Transferable {
public static final DataFlavor DRAG_IMAGE_DATA_FLAVOR = new DataFlavor(List.class, "Images");
private DragImages dragImages;
public ImageTransferable(DragImages dragImages) {
this.dragImages = dragImages;
}
@Override
public DataFlavor[] getTransferDataFlavors() {
return new DataFlavor[]{DRAG_IMAGE_DATA_FLAVOR};
}
@Override
public boolean isDataFlavorSupported(DataFlavor flavor) {
return DRAG_IMAGE_DATA_FLAVOR.equals(flavor);
}
@Override
public Object getTransferData(DataFlavor flavor) throws UnsupportedFlavorException, IOException {
return dragImages;
}
}
public class DragImage {
private Image image;
private Point p;
public DragImage(Image image, Point p) {
this.image = image;
this.p = p;
}
public Image getImage() {
return image;
}
public Point getLocation() {
return p;
}
public Dimension getSize() {
return new Dimension(image.getWidth(null), image.getHeight(null));
}
public boolean contains(Point p) {
return new Rectangle(getLocation(), getSize()).contains(p);
}
}
public class DragImages {
private Point offset;
private List<DragImage> images;
public DragImages(Point offset, DragImage... images) {
this.offset = offset;
this.images = Arrays.asList(images);
}
public Point getOffset() {
return offset;
}
public List<DragImage> getImages() {
return images;
}
}
protected class DragGestureHandler implements DragGestureListener {
private ImagePane imagePane;
public DragGestureHandler(ImagePane list) {
this.imagePane = list;
}
@Override
public void dragGestureRecognized(DragGestureEvent dge) {
DragImage di = imagePane.getImageAt(dge.getDragOrigin());
if (di != null) {
Point origin = dge.getDragOrigin();
Point p = new Point();
p.x = origin.x - di.getLocation().x;
p.y = origin.y - di.getLocation().y;
Transferable t = new ImageTransferable(new DragImages(p, di));
imagePane.removeImage(di);
DragSource ds = dge.getDragSource();
ds.startDrag(
dge,
null,
t,
new DragSourceHandler(imagePane));
}
}
}
protected class DragSourceHandler implements DragSourceListener {
private ImagePane pane;
public DragSourceHandler(ImagePane pane) {
this.pane = pane;
}
public void dragEnter(DragSourceDragEvent dsde) {
}
public void dragOver(DragSourceDragEvent dsde) {
pane.repaint();
}
public void dropActionChanged(DragSourceDragEvent dsde) {
}
public void dragExit(DragSourceEvent dse) {
}
public void dragDropEnd(DragSourceDropEvent dsde) {
if (!dsde.getDropSuccess()) {
Transferable t = dsde.getDragSourceContext().getTransferable();
if (t != null) {
try {
Object transferData = t.getTransferData(ImageTransferable.DRAG_IMAGE_DATA_FLAVOR);
if (transferData instanceof DragImages) {
DragImages di = (DragImages) transferData;
pane.addImages(di);
}
} catch (UnsupportedFlavorException | IOException ex) {
ex.printStackTrace();
}
}
}
}
}
protected class DropTargetHandler implements DropTargetListener {
private ImagePane panel;
public DropTargetHandler(ImagePane panel) {
this.panel = panel;
}
public void dragEnter(DropTargetDragEvent dtde) {
if (dtde.getTransferable().isDataFlavorSupported(ImageTransferable.DRAG_IMAGE_DATA_FLAVOR)) {
dtde.acceptDrag(DnDConstants.ACTION_COPY_OR_MOVE);
updateDragImages(dtde);
} else {
dtde.rejectDrag();
}
}
public void dragOver(DropTargetDragEvent dtde) {
updateDragImages(dtde);
panel.repaint();
}
public void dropActionChanged(DropTargetDragEvent dtde) {
}
public void dragExit(DropTargetEvent dte) {
panel.setDragImages(null);
}
public void drop(DropTargetDropEvent dtde) {
panel.setDragImages(null);
if (dtde.getTransferable().isDataFlavorSupported(ImageTransferable.DRAG_IMAGE_DATA_FLAVOR)) {
Transferable t = dtde.getTransferable();
if (t.isDataFlavorSupported(ImageTransferable.DRAG_IMAGE_DATA_FLAVOR)) {
try {
Object transferData = t.getTransferData(ImageTransferable.DRAG_IMAGE_DATA_FLAVOR);
if (transferData instanceof DragImages) {
DragImages images = (DragImages) transferData;
dtde.dropComplete(true);
dtde.acceptDrop(DnDConstants.ACTION_COPY_OR_MOVE);
panel.addImagesAt(dtde.getLocation(), images);
} else {
dtde.rejectDrop();
}
} catch (UnsupportedFlavorException ex) {
ex.printStackTrace();
dtde.rejectDrop();
} catch (IOException ex) {
ex.printStackTrace();
dtde.rejectDrop();
}
} else {
dtde.rejectDrop();
}
}
}
protected void updateDragImages(DropTargetDragEvent dtde) {
panel.setDragImages(null);
Transferable t = dtde.getTransferable();
if (t != null) {
try {
Object transferData = t.getTransferData(ImageTransferable.DRAG_IMAGE_DATA_FLAVOR);
if (transferData instanceof DragImages) {
panel.setDragPoint(dtde.getLocation());
panel.setDragImages((DragImages)transferData);
}
} catch (UnsupportedFlavorException | IOException ex) {
ex.printStackTrace();
}
}
}
}
}
内容总结
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