java的拖放 [英] java drag and drop
本文介绍了java的拖放的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我试图让familar在Java拖放，但所有我发现教程中......（让我生气了）
I try to get familar with drag and drop in java but all the tutorials I found were... (getting me angry)
我要的是从一个JList，（包含在一个名为UserPanel一个自制的JPanel）拖动PublicUserLabel，并从JTabbedPanel inerited一个自制类删除它。
它拖动对象本身，是非常重要的不是它的stringre presentation！
All I want is to drag a "PublicUserLabel" from a JList (included in a selfmade JPanel called "UserPanel") and drop it in a selfmade class inerited from JTabbedPanel. It is very important to drag the object itself and not its stringrepresentation!!!
这是我到目前为止有：
PublicUserLabel
That is what I have so far: PublicUserLabel
public class PublicUserLabel extends JLabel implements DragSourceListener, DragGestureListener, Transferable
{
private DragSource ds;
private PublicUser user;
public PublicUserLabel(PublicUser user)
{
super(user.getName());
this.user = user;
ds = new DragSource();
ds.createDefaultDragGestureRecognizer(this, DnDConstants.ACTION_COPY_OR_MOVE, this);
}
@Override
public void dragGestureRecognized(DragGestureEvent e)
{
ds.startDrag(e, DragSource.DefaultCopyDrop, this, this);
}
@Override
public Object getTransferData(DataFlavor flavor) throws UnsupportedFlavorException, IOException
{
if (flavor.equals(PublicUserFlavor.publicUserFlavor))
{
return this;//TODO ?
}
throw new UnsupportedFlavorException(flavor);
}
@Override
public DataFlavor[] getTransferDataFlavors()
{
DataFlavor[] df = new DataFlavor[2];
df[0] = DataFlavor.stringFlavor;
df[1] = PublicUserFlavor.publicUserFlavor;
return df;
}
@Override
public boolean isDataFlavorSupported(DataFlavor flavor)
{
return flavor.equals(PublicUserFlavor.publicUserFlavor);
}
//some more methods
}
UserPanel：
UserPanel:
public class UserPanel extends JPanel
{
private JTextField search;
private List<PublicUser> allUser;
private JList<PublicUserLabel> list;
private JScrollPane scrollPane;
private DefaultListModel<PublicUserLabel> listModel;
public UserPanel()
{
allUser = new LinkedList<PublicUser>();
listModel = new DefaultListModel<PublicUserLabel>();
list = new JList<PublicUserLabel>(listModel);
list.setDragEnabled(true);
PublicUserFlavor：
PublicUserFlavor:
public class PublicUserFlavor extends DataFlavor
{
public static DataFlavor publicUserFlavor;
static
{
publicUserFlavor = new DataFlavor(PublicUser.class, "PublicUser");
}
}
的TabPanel：
TabPanel:
public class TabPanel extends JTabbedPane implements DropTargetListener
{
public TabPanel()
{
setTabPlacement(JTabbedPane.BOTTOM);
addNewTabComponent("bla");
addNewTabComponent("blub");
setDropTarget(new DropTarget(this, this));
}
@Override
public void drop(DropTargetDropEvent e)
{
Transferable transferable = e.getTransferable();
if (transferable.isDataFlavorSupported(PublicUserFlavor.publicUserFlavor))
{
e.acceptDrop(DnDConstants.ACTION_COPY_OR_MOVE);
try
{
Object o = transferable.getTransferData(PublicUserFlavor.publicUserFlavor);
System.out.println(o);
if (o instanceof PublicUserLabel)
{
PublicUserLabel l = (PublicUserLabel)o;
PublicUser u = l.getUser();
System.out.println(u);
}
}
catch (UnsupportedFlavorException e1)
{
// TODO Auto-generated catch block
e1.printStackTrace();
}
catch (IOException e1)
{
// TODO Auto-generated catch block
e1.printStackTrace();
}
e.getDropTargetContext().dropComplete(true);
}
}
在滴法是，如果用户是在面板DROP掉要执行的一些syso的。但是，这不是事实。我做得不对完全地？
感谢您帮助！
In the drop method are some syso's that shall be executed if a User is droped in the panel. But that is not the fact. Am I doing something completly wrong? Thank you for helping!
推荐答案
的主要问题，我可以看到的是你是混合两种不同的API。您同时使用水平低D'n'D API和新的组件D'n'DAPI。
The major issues I can see are you are mixing two different API's. You're using both the low level D'n'D API and the newer "component D'n'D" API.
就个人而言，较新的API让我很烦，所以我倾向于避免它。
Personally, the newer API annoys me, so I tend to avoid it.
我不明白为什么你需要转移的标签，当它会更好地转移标的 PublicUser 对象，不过这只是我的。
I can't see why you need to transfer the label, when it would be better to transfer the underlying PublicUser object, but that's just me.
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();
}
}
}
}
}
这篇关于java的拖放的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
查看全文
