A TransferHandler and JTextArea that will accept any drop at all
/*
Java Swing, 2nd Edition
By Marc Loy, Robert Eckstein, Dave Wood, James Elliott, Brian Cole
ISBN: 0-596-00408-7
Publisher: O'Reilly
*/
// UTest.java
//A test frame work for the UberHandler drop handler. This version has
//no fancy Unicode characters for ease of use. (Note that "ease of use"
//only applys to humans...the Java tools are quite happy with Unicode
//characters. Not all text editors are, though...)
//
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.Transferable;
import java.io.BufferedReader;
import java.io.Reader;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.TransferHandler;
public class UTest {
public static void main(String args[]) {
JFrame frame = new JFrame("Debugging Drop Zone");
frame.setSize(500, 300);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JTextArea jta = new JTextArea();
frame.getContentPane().add(new JScrollPane(jta));
UberHandler uh = new UberHandler();
uh.setOutput(jta);
jta.setTransferHandler(uh);
frame.setVisible(true);
}
}
//UberHandler.java
//A TransferHandler that will accept any drop at all. If a text area is
//registered, debugging information will be sent there. Otherwise, all
//debug information will be sent to stdout.
//
class UberHandler extends TransferHandler {
JTextArea output;
public void TransferHandler() {
}
public boolean canImport(JComponent dest, DataFlavor[] flavors) {
// you bet we can!
return true;
}
public boolean importData(JComponent src, Transferable transferable) {
// Ok, here's the tricky part...
println("Receiving data from " + src);
println("Transferable object is: " + transferable);
println("Valid data flavors: ");
DataFlavor[] flavors = transferable.getTransferDataFlavors();
DataFlavor listFlavor = null;
DataFlavor objectFlavor = null;
DataFlavor readerFlavor = null;
int lastFlavor = flavors.length - 1;
// Check the flavors and see if we find one we like.
// If we do, save it.
for (int f = 0; f <= lastFlavor; f++) {
println(" " + flavors[f]);
if (flavors[f].isFlavorJavaFileListType()) {
listFlavor = flavors[f];
}
if (flavors[f].isFlavorSerializedObjectType()) {
objectFlavor = flavors[f];
}
if (flavors[f].isRepresentationClassReader()) {
readerFlavor = flavors[f];
}
}
// Ok, now try to display the content of the drop.
try {
DataFlavor bestTextFlavor = DataFlavor
.selectBestTextFlavor(flavors);
BufferedReader br = null;
String line = null;
if (bestTextFlavor != null) {
println("Best text flavor: " + bestTextFlavor.getMimeType());
println("Content:");
Reader r = bestTextFlavor.getReaderForText(transferable);
br = new BufferedReader(r);
line = br.readLine();
while (line != null) {
println(line);
line = br.readLine();
}
br.close();
} else if (listFlavor != null) {
java.util.List list = (java.util.List) transferable
.getTransferData(listFlavor);
println(list);
} else if (objectFlavor != null) {
println("Data is a java object:\n"
+ transferable.getTransferData(objectFlavor));
} else if (readerFlavor != null) {
println("Data is an InputStream:");
br = new BufferedReader((Reader) transferable
.getTransferData(readerFlavor));
line = br.readLine();
while (line != null) {
println(line);
}
br.close();
} else {
// Don't know this flavor type yet...
println("No text representation to show.");
}
println("\n\n");
} catch (Exception e) {
println("Caught exception decoding transfer:");
println(e);
return false;
}
return true;
}
public void exportDone(JComponent source, Transferable data, int action) {
// Just let us know when it occurs...
System.err.println("Export Done.");
}
public void setOutput(JTextArea jta) {
output = jta;
}
protected void print(Object o) {
print(o.toString());
}
protected void print(String s) {
if (output != null) {
output.append(s);
} else {
System.out.println(s);
}
}
protected void println(Object o) {
println(o.toString());
}
protected void println(String s) {
if (output != null) {
output.append(s);
output.append("\n");
} else {
System.out.println(s);
}
}
protected void println() {
println("");
}
public static void main(String args[]) {
JFrame frame = new JFrame("Debugging Drop Zone");
frame.setSize(500, 300);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JTextArea jta = new JTextArea();
frame.getContentPane().add(new JScrollPane(jta));
UberHandler uh = new UberHandler();
uh.setOutput(jta);
jta.setTransferHandler(uh);
frame.setVisible(true);
}
}
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