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所以我为我的应用程序编写了一个TransferHandler（沿着Oracle站点的示例），但是当我尝试移动数据时它并未移动。它所做的就是复制索引处的数据（n-1，即，如果我正在移动并且项目到n位置）来索引n。你能否请检查什么是错误的，虽然我尝试了很多选择，但没有一个为我工作。在JList中拖放不起作用
import javax.swing.TransferHandler;
import javax.swing.*;
import java.awt.datatransfer.*;
public class ListTransferHandler extends TransferHandler {
private int[] indices = null;
private int addIndex = -1; //Location where items were added
private int addCount = 0; //Number of items added.
public boolean canImport(TransferHandler.TransferSupport info) {
// Check for String flavor
if (!info.isDataFlavorSupported(DataFlavor.stringFlavor)) {
return false;
}
return true;
}
protected Transferable createTransferable(JComponent c) {
return new StringSelection(exportString(c));
}
public int getSourceActions(JComponent c) {
return TransferHandler.MOVE;
}
public boolean importData(TransferHandler.TransferSupport info) {
if (!info.isDrop()) {
return false;
}
JList list = (JList)info.getComponent();
DefaultListModel listModel = (DefaultListModel)list.getModel();
JList.DropLocation dl = (JList.DropLocation)info.getDropLocation();
int index = dl.getIndex();
boolean insert = dl.isInsert();
// Get the string that is being dropped.
Transferable t = info.getTransferable();
String data;
try {
data = (String)t.getTransferData(DataFlavor.stringFlavor);
}
catch (Exception e) { return false; }
// Perform the actual import.
if (insert) {
listModel.add(index, data);
} else {
listModel.set(index, data);
}
return true;
}
protected void exportDone(JComponent c, Transferable data, int action) {
cleanup(c, action == TransferHandler.MOVE);
}
//Bundle up the selected items in the list
//as a single string, for export.
protected String exportString(JComponent c) {
JList list = (JList)c;
indices = list.getSelectedIndices();
Object[] values = list.getSelectedValues();
StringBuffer buff = new StringBuffer();
for (int i = 0; i < values.length; i++) {
Object val = values[i];
buff.append(val == null ? "" : val.toString());
if (i != values.length - 1) {
buff.append("\n");
}
}
return buff.toString();
}
//Take the incoming string and wherever there is a
//newline, break it into a separate item in the list.
protected void importString(JComponent c, String str) {
JList target = (JList)c;
DefaultListModel listModel = (DefaultListModel)target.getModel();
int index = target.getSelectedIndex();
//Prevent the user from dropping data back on itself.
//For example, if the user is moving items #4,#5,#6 and #7 and
//attempts to insert the items after item #5, this would
//be problematic when removing the original items.
//So this is not allowed.
if (indices != null && index >= indices[0] - 1 &&
index <= indices[indices.length - 1]) {
indices = null;
return;
}
int max = listModel.getSize();
if (index < 0) {
index = max;
} else {
index++;
if (index > max) {
index = max;
}
}
addIndex = index;
String[] values = str.split("\n");
addCount = values.length;
for (int i = 0; i < values.length; i++) {
listModel.add(index++, values[i]);
}
}
//If the remove argument is true, the drop has been
//successful and it's time to remove the selected items
//from the list. If the remove argument is false, it
//was a Copy operation and the original list is left
//intact.
protected void cleanup(JComponent c, boolean remove) {
if (remove && indices != null) {
JList source = (JList)c;
DefaultListModel model = (DefaultListModel)source.getModel();
//If we are moving items around in the same list, we
//need to adjust the indices accordingly, since those
//after the insertion point have moved.
if (addCount > 0) {
for (int i = 0; i < indices.length; i++) {
if (indices[i] > addIndex) {
indices[i] += addCount;
}
}
}
for (int i = indices.length - 1; i >= 0; i--) {
model.remove(indices[i]);
}
}
indices = null;
addCount = 0;
addIndex = -1;
}
}