(DnD を使用して) 並べ替える機能を備えたサムネイルを表示する必要があるサムネイル ビューアーのアプリケーションがあります。
サムネイルはカスタム コンポーネント ( JLayeredPane ) です。
より良いアイデアを得るために、アプリケーションのワイヤーフレームを次に示します。
達成するための指示/ポインター、または並べ替え機能を実行できる既存のコンポーネントは、非常に役立ちます。
各要素をサムネイルとして JList を使用できますか?
注: ここにコードがあるとは思っていません。
私は基本的にこれをウェブから盗み、少し修正しました...
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.Transferable;
import java.awt.datatransfer.UnsupportedFlavorException;
import java.io.IOException;
import java.util.ArrayList;
import javax.swing.BorderFactory;
import javax.swing.DefaultListModel;
import javax.swing.DropMode;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.ListSelectionModel;
import javax.swing.TransferHandler;
public class TestListReorder extends JPanel {
ArrayListTransferHandler arrayListHandler;
public TestListReorder() {
arrayListHandler = new ArrayListTransferHandler();
JList list1, list2;
DefaultListModel list1Model = new DefaultListModel();
list1Model.addElement("0 (list 1)");
list1Model.addElement("1 (list 1)");
list1Model.addElement("2 (list 1)");
list1Model.addElement("3 (list 1)");
list1Model.addElement("4 (list 1)");
list1Model.addElement("5 (list 1)");
list1Model.addElement("6 (list 1)");
list1 = new JList(list1Model);
list1.setDropMode(DropMode.USE_SELECTION);
list1.setSelectionMode(ListSelectionModel.SINGLE_INTERVAL_SELECTION);
list1.setTransferHandler(arrayListHandler);
list1.setDragEnabled(true);
JScrollPane list1View = new JScrollPane(list1);
list1View.setPreferredSize(new Dimension(200, 100));
JPanel panel1 = new JPanel();
panel1.setLayout(new BorderLayout());
panel1.add(list1View, BorderLayout.CENTER);
panel1.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
setLayout(new BorderLayout());
add(panel1, BorderLayout.LINE_START);
setBorder(BorderFactory.createEmptyBorder(20, 20, 20, 20));
}
/**
* Create the GUI and show it. For thread safety, this method should be
* invoked from the event-dispatching thread.
*/
private static void createAndShowGUI() {
//Make sure we have nice window decorations.
JFrame.setDefaultLookAndFeelDecorated(true);
//Create and set up the window.
JFrame frame = new JFrame("DragListDemo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//Create and set up the content pane.
TestListReorder demo = new TestListReorder();
frame.setContentPane(demo);
//Display the window.
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
//Schedule a job for the event-dispatching thread:
//creating and showing this application's GUI.
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
}
/*
* ArrayListTransferHandler.java is used by the 1.4 DragListDemo.java example.
*/
class ArrayListTransferHandler extends TransferHandler {
DataFlavor localArrayListFlavor, serialArrayListFlavor;
String localArrayListType = DataFlavor.javaJVMLocalObjectMimeType
+ ";class=java.util.ArrayList";
JList source = null;
int[] indices = null;
int addIndex = -1; //Location where items were added
int addCount = 0; //Number of items added
public ArrayListTransferHandler() {
try {
localArrayListFlavor = new DataFlavor(localArrayListType);
} catch (ClassNotFoundException e) {
System.out
.println("ArrayListTransferHandler: unable to create data flavor");
}
serialArrayListFlavor = new DataFlavor(ArrayList.class, "ArrayList");
}
public boolean importData(JComponent c, Transferable t) {
JList target = null;
ArrayList alist = null;
if (!canImport(c, t.getTransferDataFlavors())) {
return false;
}
try {
target = (JList) c;
if (hasLocalArrayListFlavor(t.getTransferDataFlavors())) {
alist = (ArrayList) t.getTransferData(localArrayListFlavor);
} else if (hasSerialArrayListFlavor(t.getTransferDataFlavors())) {
alist = (ArrayList) t.getTransferData(serialArrayListFlavor);
} else {
return false;
}
} catch (UnsupportedFlavorException ufe) {
System.out.println("importData: unsupported data flavor");
return false;
} catch (IOException ioe) {
System.out.println("importData: I/O exception");
return false;
}
//At this point we use the same code to retrieve the data
//locally or serially.
//We'll drop at the current selected index.
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.
//This is interpreted as dropping the same data on itself
//and has no effect.
if (source.equals(target)) {
if (indices != null && index >= indices[0] - 1
&& index <= indices[indices.length - 1]) {
indices = null;
return true;
}
}
DefaultListModel listModel = (DefaultListModel) target.getModel();
int max = listModel.getSize();
if (index < 0) {
index = max;
} else {
index++;
if (index > max) {
index = max;
}
}
addIndex = index;
addCount = alist.size();
for (int i = 0; i < alist.size(); i++) {
listModel.add(index++, alist.get(i));
}
return true;
}
protected void exportDone(JComponent c, Transferable data, int action) {
if ((action == MOVE) && (indices != null)) {
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;
addIndex = -1;
addCount = 0;
}
private boolean hasLocalArrayListFlavor(DataFlavor[] flavors) {
if (localArrayListFlavor == null) {
return false;
}
for (int i = 0; i < flavors.length; i++) {
if (flavors[i].equals(localArrayListFlavor)) {
return true;
}
}
return false;
}
private boolean hasSerialArrayListFlavor(DataFlavor[] flavors) {
if (serialArrayListFlavor == null) {
return false;
}
for (int i = 0; i < flavors.length; i++) {
if (flavors[i].equals(serialArrayListFlavor)) {
return true;
}
}
return false;
}
public boolean canImport(JComponent c, DataFlavor[] flavors) {
if (hasLocalArrayListFlavor(flavors)) {
return true;
}
if (hasSerialArrayListFlavor(flavors)) {
return true;
}
return false;
}
protected Transferable createTransferable(JComponent c) {
if (c instanceof JList) {
source = (JList) c;
indices = source.getSelectedIndices();
Object[] values = source.getSelectedValues();
if (values == null || values.length == 0) {
return null;
}
ArrayList alist = new ArrayList(values.length);
for (int i = 0; i < values.length; i++) {
Object o = values[i];
String str = o.toString();
if (str == null) {
str = "";
}
alist.add(str);
}
return new ArrayListTransferable(alist);
}
return null;
}
public int getSourceActions(JComponent c) {
return COPY_OR_MOVE;
}
public class ArrayListTransferable implements Transferable {
ArrayList data;
public ArrayListTransferable(ArrayList alist) {
data = alist;
}
public Object getTransferData(DataFlavor flavor)
throws UnsupportedFlavorException {
if (!isDataFlavorSupported(flavor)) {
throw new UnsupportedFlavorException(flavor);
}
return data;
}
public DataFlavor[] getTransferDataFlavors() {
return new DataFlavor[]{localArrayListFlavor,
serialArrayListFlavor};
}
public boolean isDataFlavorSupported(DataFlavor flavor) {
if (localArrayListFlavor.equals(flavor)) {
return true;
}
if (serialArrayListFlavor.equals(flavor)) {
return true;
}
return false;
}
}
}
元の投稿はこちらでご覧いただけます。
個人的には、新しい「コンポーネント」のドラッグ アンド ドロップ API は好きではありませんが、あなたのケースでは、実装するのが最も簡単で最速かもしれません...
これはかなりうまく機能しますが、元のコードにはバグが含まれているため、エラー メッセージを表示せずに複数のアイテムを一度に移動することはできません。
protected void exportDone(JComponent c, Transferable data, int action) {
if ((action == MOVE) && (indices != null)) {
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.
for (int i = indices.length - 1; i >= 0; i--)
model.remove(indices[i]);
}
if (addCount > 0) {
for (int i = 0; i < indices.length; i++) {
if (indices[i] > addIndex) {
indices[i] += addCount;
}
}
}
indices = null;
addIndex = -1;
addCount = 0;
}