Java by API/java.awt.datatransfer/Transferable
Содержание
implements Transferable
<source lang="java">
import java.awt.BorderLayout; import java.awt.Image; import java.awt.datatransfer.DataFlavor; import java.awt.datatransfer.Transferable; import java.awt.datatransfer.UnsupportedFlavorException; import java.awt.event.MouseAdapter; import java.awt.event.MouseEvent; import java.awt.event.MouseListener; import java.io.IOException; import javax.swing.AbstractButton; import javax.swing.Icon; import javax.swing.ImageIcon; import javax.swing.JComponent; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JScrollPane; import javax.swing.TransferHandler; public class MainClass {
public static void main(String args[]) {
JFrame frame = new JFrame("Drag Image");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Icon icon = new ImageIcon("image.jpg");
JLabel label = new JLabel(icon);
label.setTransferHandler(new ImageSelection());
MouseListener listener = new MouseAdapter() {
public void mousePressed(MouseEvent me) {
JComponent comp = (JComponent) me.getSource();
TransferHandler handler = comp.getTransferHandler();
handler.exportAsDrag(comp, me, TransferHandler.COPY);
}
};
label.addMouseListener(listener);
frame.add(new JScrollPane(label), BorderLayout.CENTER);
frame.setSize(300, 150);
frame.setVisible(true);
}
} class ImageSelection extends TransferHandler implements Transferable {
private static final DataFlavor flavors[] = { DataFlavor.imageFlavor };
private Image image;
public int getSourceActions(JComponent c) {
return TransferHandler.COPY;
}
public boolean canImport(JComponent comp, DataFlavor flavor[]) {
if (!(comp instanceof JLabel) && !(comp instanceof AbstractButton)) {
return false;
}
for (int i = 0, n = flavor.length; i < n; i++) {
for (int j = 0, m = flavors.length; j < m; j++) {
if (flavor[i].equals(flavors[j])) {
return true;
}
}
}
return false;
}
public Transferable createTransferable(JComponent comp) {
image = null;
if (comp instanceof JLabel) {
JLabel label = (JLabel) comp;
Icon icon = label.getIcon();
if (icon instanceof ImageIcon) {
image = ((ImageIcon) icon).getImage();
return this;
}
} else if (comp instanceof AbstractButton) {
AbstractButton button = (AbstractButton) comp;
Icon icon = button.getIcon();
if (icon instanceof ImageIcon) {
image = ((ImageIcon) icon).getImage();
return this;
}
}
return null;
}
public boolean importData(JComponent comp, Transferable t) {
if (comp instanceof JLabel) {
JLabel label = (JLabel) comp;
if (t.isDataFlavorSupported(flavors[0])) {
try {
image = (Image) t.getTransferData(flavors[0]);
ImageIcon icon = new ImageIcon(image);
label.setIcon(icon);
return true;
} catch (UnsupportedFlavorException ignored) {
} catch (IOException ignored) {
}
}
} else if (comp instanceof AbstractButton) {
AbstractButton button = (AbstractButton) comp;
if (t.isDataFlavorSupported(flavors[0])) {
try {
image = (Image) t.getTransferData(flavors[0]);
ImageIcon icon = new ImageIcon(image);
button.setIcon(icon);
return true;
} catch (UnsupportedFlavorException ignored) {
} catch (IOException ignored) {
}
}
}
return false;
}
public Object getTransferData(DataFlavor flavor) {
if (isDataFlavorSupported(flavor)) {
return image;
}
return null;
}
public DataFlavor[] getTransferDataFlavors() {
return flavors;
}
public boolean isDataFlavorSupported(DataFlavor flavor) {
return flavors[0].equals(flavor);
}
}
</source>
Transferable: getTransferData(DataFlavor flavor)
<source lang="java">
import java.awt.BorderLayout; import java.awt.Color; import java.awt.datatransfer.DataFlavor; import java.awt.datatransfer.StringSelection; 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.DragSource; import java.awt.dnd.DragSourceContext; 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.dnd.InvalidDnDOperationException; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JLabel; public class MainClass extends JFrame implements ActionListener, DropTargetListener {
DragLabel source = new DragLabel("Drag and drop me to the following JButton", JLabel.CENTER);
JButton target = new JButton();
MainClass(String title) {
super(title);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
source.setForeground(Color.red);
getContentPane().add(source, BorderLayout.NORTH);
target.addActionListener(this);
getContentPane().add(target, BorderLayout.SOUTH);
new DropTarget(target, DnDConstants.ACTION_COPY_OR_MOVE, this);
setSize(205, 100);
setVisible(true);
}
public void actionPerformed(ActionEvent e) {
JButton b = (JButton) e.getSource();
b.setText("");
source.setText("Drag and drop me to the following JButton");
}
public void dragEnter(DropTargetDragEvent e) {
System.out.println("Entering drop target #1");
}
public void dragExit(DropTargetEvent e) {
System.out.println("Exiting drop target #1");
}
public void dragOver(DropTargetDragEvent e) {
System.out.println("Dragging over drop target #1");
}
public void drop(DropTargetDropEvent e) {
System.out.println("Dropping");
try {
Transferable t = e.getTransferable();
if (e.isDataFlavorSupported(DataFlavor.stringFlavor)) {
e.acceptDrop(e.getDropAction());
String s;
s = (String) t.getTransferData(DataFlavor.stringFlavor);
target.setText(s);
e.dropComplete(true);
} else
e.rejectDrop();
} catch (java.io.IOException e2) {
} catch (UnsupportedFlavorException e2) {
}
}
public void dropActionChanged(DropTargetDragEvent e) {
System.out.println("Drop action changed #1");
}
public static void main(String[] args) {
new MainClass("Drag and Drop Demo");
}
} class DragLabel extends JLabel implements DragGestureListener, DragSourceListener {
private DragSource ds = DragSource.getDefaultDragSource();
public DragLabel(String s, int alignment) {
super(s, alignment);
int action = DnDConstants.ACTION_COPY_OR_MOVE;
ds.createDefaultDragGestureRecognizer(this, action, this);
}
public void dragGestureRecognized(DragGestureEvent e) {
try {
Transferable t = new StringSelection(getText());
e.startDrag(DragSource.DefaultCopyNoDrop, t, this);
} catch (InvalidDnDOperationException e2) {
System.out.println(e2);
}
}
public void dragDropEnd(DragSourceDropEvent e) {
System.out.println("Drag and drop end");
if (e.getDropSuccess() == false) {
System.out.println("unsuccessful");
return;
}
int action = e.getDropAction();
if ((action & DnDConstants.ACTION_MOVE) != 0)
setText("");
}
public void dragEnter(DragSourceDragEvent e) {
System.out.println("Entering drop target #2");
DragSourceContext ctx = e.getDragSourceContext();
int action = e.getDropAction();
if ((action & DnDConstants.ACTION_COPY) != 0)
ctx.setCursor(DragSource.DefaultCopyDrop);
else
ctx.setCursor(DragSource.DefaultCopyNoDrop);
}
public void dragExit(DragSourceEvent e) {
System.out.println("Exiting drop target #2");
}
public void dragOver(DragSourceDragEvent e) {
System.out.println("Dragging over drop target #2");
}
public void dropActionChanged(DragSourceDragEvent e) {
System.out.println("Drop action changed #2");
}
}
</source>
Transferable: getTransferDataFlavors()
<source lang="java">
import java.awt.Toolkit; import java.awt.datatransfer.DataFlavor; import java.awt.datatransfer.Transferable; import java.awt.datatransfer.UnsupportedFlavorException; import java.io.File; import java.io.IOException; import java.net.MalformedURLException; import java.net.URL; import java.util.Iterator; import java.util.List; import javax.swing.JComponent; import javax.swing.JFrame; import javax.swing.TransferHandler; public class MainClass extends JFrame {
public MainClass() {
super("Drop Target");
JComponent cp = (JComponent) getContentPane();
cp.setTransferHandler(new MyFileTransferHandler()); // see below
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setSize(150, 150);
}
public static void main(String[] args) {
new MainClass().setVisible(true);
}
} class MyFileTransferHandler extends TransferHandler {
public boolean canImport(JComponent com, DataFlavor[] dataFlavors) {
for (int i = 0; i < dataFlavors.length; i++) {
DataFlavor flavor = dataFlavors[i];
if (flavor.equals(DataFlavor.javaFileListFlavor)) {
System.out.println("canImport: JavaFileList FLAVOR: " + flavor);
return true;
}
if (flavor.equals(DataFlavor.stringFlavor)) {
System.out.println("canImport: String FLAVOR: " + flavor);
return true;
}
System.err.println("canImport: Rejected Flavor: " + flavor);
}
return false;
}
public boolean importData(JComponent comp, Transferable t) {
DataFlavor[] flavors = t.getTransferDataFlavors();
System.out.println("Trying to import:" + t);
for (int i = 0; i < flavors.length; i++) {
DataFlavor flavor = flavors[i];
try {
if (flavor.equals(DataFlavor.javaFileListFlavor)) {
System.out.println("importData: FileListFlavor");
List l = (List) t.getTransferData(DataFlavor.javaFileListFlavor);
Iterator iter = l.iterator();
while (iter.hasNext()) {
File file = (File) iter.next();
System.out.println("GOT FILE: " + file.getCanonicalPath());
}
return true;
} else if (flavor.equals(DataFlavor.stringFlavor)) {
System.out.println("importData: String Flavor");
String fileOrURL = (String) t.getTransferData(flavor);
System.out.println("GOT STRING: " + fileOrURL);
try {
URL url = new URL(fileOrURL);
System.out.println("Valid URL: " + url.toString());
return true;
} catch (MalformedURLException ex) {
System.err.println("Not a valid URL");
return false;
}
} else {
System.out.println("importData rejected: " + flavor);
}
} catch (IOException ex) {
System.err.println("IOError getting data: " + ex);
} catch (UnsupportedFlavorException e) {
System.err.println("Unsupported Flavor: " + e);
}
}
return false;
}
}
</source>
Transferable: isDataFlavorSupported(DataFlavor flavor)
<source lang="java">
import java.awt.Toolkit; import java.awt.datatransfer.Clipboard; import java.awt.datatransfer.DataFlavor; import java.awt.datatransfer.StringSelection; import java.awt.datatransfer.Transferable; import java.awt.datatransfer.UnsupportedFlavorException; import java.io.IOException; public class Main {
public static void main(String args[]) {
String toClipboard = "Hello from Java!";
StringSelection ss = new StringSelection(toClipboard);
Clipboard clip = Toolkit.getDefaultToolkit().getSystemClipboard();
clip.setContents(ss, ss);
clip = Toolkit.getDefaultToolkit().getSystemClipboard();
Transferable contents = clip.getContents(new Main().getClass());
if (contents == null) {
System.out.println("The clipboard is empty.");
return;
}
if (contents.isDataFlavorSupported(DataFlavor.stringFlavor)) {
try {
String data = (String) contents.getTransferData(DataFlavor.stringFlavor);
System.out.println(data);
} catch (IOException ex) {
System.out.println("IOException");
} catch (UnsupportedFlavorException ex) {
System.out.println("UnsupportedFlavorException");
}
} else{
System.out.println("Wrong flavor.");
}
}
}
</source>
