我有一个 JList,并希望用户能够使用拖放功能对列表中的元素重新排序(使用我自己的 ListModel 和 ListCellRenderer,如果这有什么不同的话)。我需要创建哪些对象,以及如何处理该操作?
修改后的 Jan Taccis 答案:
public class DndTest extends JFrame {
JList<String> myList;
DefaultListModel<String> myListModel;
public DndTest() {
myListModel = createStringListModel();
myList = new JList<String>(myListModel);
MyMouseAdaptor myMouseAdaptor = new MyMouseAdaptor();
myList.addMouseListener(myMouseAdaptor);
myList.addMouseMotionListener(myMouseAdaptor);
JPanel content = new JPanel();
content.add(myList);
this.add(content);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.pack();
this.setVisible(true);
}
private class MyMouseAdaptor extends MouseInputAdapter {
private boolean mouseDragging = false;
private int dragSourceIndex;
@Override
public void mousePressed(MouseEvent e) {
if (SwingUtilities.isLeftMouseButton(e)) {
dragSourceIndex = myList.getSelectedIndex();
mouseDragging = true;
}
}
@Override
public void mouseReleased(MouseEvent e) {
mouseDragging = false;
}
@Override
public void mouseDragged(MouseEvent e) {
if (mouseDragging) {
int currentIndex = myList.locationToIndex(e.getPoint());
if (currentIndex != dragSourceIndex) {
int dragTargetIndex = myList.getSelectedIndex();
String dragElement = myListModel.get(dragSourceIndex);
myListModel.remove(dragSourceIndex);
myListModel.add(dragTargetIndex, dragElement);
dragSourceIndex = currentIndex;
}
}
}
}
private DefaultListModel<String> createStringListModel() {
final String[] listElements = new String[] { "Cat", "Dog", "Cow", "Horse", "Pig", "Monkey" };
DefaultListModel<String> listModel = new DefaultListModel<String>();
for (String element : listElements) {
listModel.addElement(element);
}
return listModel;
}
public static void main(String[] args) {
new DndTest();
}
}
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