Java 通过拖放重新排序JList
我遇到了一个关于使用拖放对JList中的元素重新排序的问题。下面的代码是对代码的修改,您可以将元素从一个JList拖到另一个JList(仅以一种方式工作)。我试图使它只对一个JList可用,但这些元素甚至无法从列表中拖出。所以我想这是不可能的。你知道我做错了什么或没有考虑到什么吗 我们的想法是让它为带有缩略图的Jlist工作,但由于我甚至不能让它只使用字符串工作。。。我已经看了好几本D'n'D教程,但还是没法让它发挥作用。 感谢您的帮助Java 通过拖放重新排序JList,java,swing,drag-and-drop,java-7,jlist,Java,Swing,Drag And Drop,Java 7,Jlist,我遇到了一个关于使用拖放对JList中的元素重新排序的问题。下面的代码是对代码的修改,您可以将元素从一个JList拖到另一个JList(仅以一种方式工作)。我试图使它只对一个JList可用,但这些元素甚至无法从列表中拖出。所以我想这是不可能的。你知道我做错了什么或没有考虑到什么吗 我们的想法是让它为带有缩略图的Jlist工作,但由于我甚至不能让它只使用字符串工作。。。我已经看了好几本D'n'D教程,但还是没法让它发挥作用。 感谢您的帮助 import javax.swing.*; import
import javax.swing.*;
import javax.swing.border.*;
import java.awt.*;
import java.awt.datatransfer.*;
import java.io.IOException;
public class DragAndDrop extends JFrame {
DefaultListModel<String> transport = new DefaultListModel<String>();
JList<String> transportList = new JList<String>(transport);
public DragAndDrop() {
setLayout(new FlowLayout());
transport.addElement("Bike");
transport.addElement("Car");
transport.addElement("Truck");
transport.addElement("Boat");
JScrollPane transportScroll = new JScrollPane(transportList);
transportScroll.setBorder(new TitledBorder("Transportation"));
add(transportScroll);
transportList.setDragEnabled(true);
transportList.setTransferHandler(new TransferHandler() {
int index;
@Override
public int getSourceActions(JComponent comp) {
return COPY_OR_MOVE;
}
@Override
public Transferable createTransferable(JComponent comp) {
index = transportList.getSelectedIndex();
return new StringSelection(transportList.getSelectedValue());
}
@Override
public void exportDone( JComponent comp, Transferable trans, int action ) {
if (action==MOVE) {
transport.remove(index);
}
}
});
transportList.setDropMode(DropMode.ON);
transportList.setTransferHandler(new TransferHandler() {
@Override
public boolean canImport(TransferHandler.TransferSupport support) {
// data of type string?
return support.isDataFlavorSupported(DataFlavor.stringFlavor);
}
@Override
public boolean importData(TransferHandler.TransferSupport support) {
try {
// convert data to string
String s = (String)support.getTransferable().getTransferData(DataFlavor.stringFlavor);
JList.DropLocation dl = (JList.DropLocation)support.getDropLocation();
transport.add(dl.getIndex(),s);
return true;
}
catch (UnsupportedFlavorException e) {}
catch (IOException e) {}
return false;
}
});
pack();
setDefaultCloseOperation(EXIT_ON_CLOSE);
setVisible(true);
}
public static void main(String[] args) {
new DragAndDrop();
}
}
import javax.swing.*;
导入javax.swing.border.*;
导入java.awt.*;
导入java.awt.datatransfer.*;
导入java.io.IOException;
公共类DragAndDrop扩展JFrame{
DefaultListModel传输=新建DefaultListModel();
JList transportList=新的JList(传输);
公共DragAndDrop(){
setLayout(新的FlowLayout());
运输.补充(“自行车”);
运输附录(“汽车”);
运输.补充(“卡车”);
运输附录(“船”);
JScrollPane transportScroll=新的JScrollPane(transportList);
运输订单(新标题边界(“运输”);
添加(滚动);
transportList.setDragEnabled(true);
setTransferHandler(新的TransferHandler(){
整数指数;
@凌驾
public int getSourceActions(JComponent comp){
返回拷贝或移动;
}
@凌驾
公共可转让或可转让(JComponent comp){
index=transportList.getSelectedIndex();
返回新的StringSelection(transportList.getSelectedValue());
}
@凌驾
公共无效导出已完成(JComponent comp、可转移的trans、int action){
如果(动作==移动){
运输。移除(索引);
}
}
});
transportList.setDropMode(DropMode.ON);
setTransferHandler(新的TransferHandler(){
@凌驾
公共布尔值canImport(TransferHandler.TransferSupport){
//字符串类型的数据?
返回support.isDataFlavorSupported(DataFlavor.stringFlavor);
}
@凌驾
公共布尔输入数据(TransferHandler.TransferSupport){
试一试{
//将数据转换为字符串
字符串s=(字符串)support.getTransferable().getTransferData(DataFlavor.stringFlavor);
JList.DropLocation dl=(JList.DropLocation)support.getDropLocation();
transport.add(dl.getIndex(),s);
返回true;
}
捕获(无支持的Lavore异常){}
捕获(IOE){}
返回false;
}
});
包装();
setDefaultCloseOperation(关闭时退出);
setVisible(真);
}
公共静态void main(字符串[]args){
新DragAndDrop();
}
}
请注意,如果这是一个重新发布,请道歉
编辑
我想我已经把它修好了:必须使用不同的TransferHandler-应该只有一个,并且包含第二个中的所有方法。请参阅DnD上Swing教程中的,以获取将放在同一个JList或另一个JList上的示例。
import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.EventQueue;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.Transferable;
import java.awt.datatransfer.UnsupportedFlavorException;
import java.awt.dnd.DragSource;
import java.io.IOException;
import java.io.Serializable;
import java.util.Arrays;
import java.util.Objects;
// import javax.activation.ActivationDataFlavor;
// import javax.activation.DataHandler;
import javax.swing.BorderFactory;
import javax.swing.DefaultListModel;
import javax.swing.DropMode;
import javax.swing.Icon;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.ListCellRenderer;
import javax.swing.ListSelectionModel;
import javax.swing.TransferHandler;
import javax.swing.UIManager;
import javax.swing.WindowConstants;
public class DragAndDropTest {
public JComponent makeUI() {
DefaultListModel<Thumbnail> m = new DefaultListModel<>();
for (String s : Arrays.asList("error", "information", "question", "warning")) {
m.addElement(new Thumbnail(s));
}
JList<Thumbnail> list = new JList<>(m);
list.getSelectionModel().setSelectionMode(
ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);
list.setTransferHandler(new ListItemTransferHandler());
list.setDropMode(DropMode.INSERT);
list.setDragEnabled(true);
// https://java-swing-tips.blogspot.com/2008/10/rubber-band-selection-drag-and-drop.html
list.setLayoutOrientation(JList.HORIZONTAL_WRAP);
list.setVisibleRowCount(0);
list.setFixedCellWidth(80);
list.setFixedCellHeight(80);
list.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));
list.setCellRenderer(new ListCellRenderer<Thumbnail>() {
private final JPanel p = new JPanel(new BorderLayout());
private final JLabel icon = new JLabel((Icon)null, JLabel.CENTER);
private final JLabel label = new JLabel("", JLabel.CENTER);
@Override
public Component getListCellRendererComponent(
JList<? extends Thumbnail> list, Thumbnail value, int index,
boolean isSelected, boolean cellHasFocus) {
icon.setIcon(value.icon);
label.setText(value.name);
label.setForeground(isSelected ? list.getSelectionForeground()
: list.getForeground());
p.add(icon);
p.add(label, BorderLayout.SOUTH);
p.setBackground(isSelected ? list.getSelectionBackground()
: list.getBackground());
return p;
}
});
return new JScrollPane(list);
}
public static void main(String[] args) {
EventQueue.invokeLater(() -> createAndShowGUI());
}
public static void createAndShowGUI() {
JFrame f = new JFrame();
f.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
f.getContentPane().add(new DragAndDropTest().makeUI());
f.setSize(320, 240);
f.setLocationRelativeTo(null);
f.setVisible(true);
}
}
class Thumbnail implements Serializable {
public final String name;
public final Icon icon;
public Thumbnail(String name) {
this.name = name;
this.icon = UIManager.getIcon("OptionPane." + name + "Icon");
}
}
// @camickr already suggested above.
// https://docs.oracle.com/javase/tutorial/uiswing/dnd/dropmodedemo.html
@SuppressWarnings("serial")
class ListItemTransferHandler extends TransferHandler {
protected final DataFlavor localObjectFlavor;
protected int[] indices;
protected int addIndex = -1; // Location where items were added
protected int addCount; // Number of items added.
public ListItemTransferHandler() {
super();
// localObjectFlavor = new ActivationDataFlavor(
// Object[].class, DataFlavor.javaJVMLocalObjectMimeType, "Array of items");
localObjectFlavor = new DataFlavor(Object[].class, "Array of items");
}
@Override
protected Transferable createTransferable(JComponent c) {
JList<?> source = (JList<?>) c;
c.getRootPane().getGlassPane().setVisible(true);
indices = source.getSelectedIndices();
Object[] transferedObjects = source.getSelectedValuesList().toArray(new Object[0]);
// return new DataHandler(transferedObjects, localObjectFlavor.getMimeType());
return new Transferable() {
@Override public DataFlavor[] getTransferDataFlavors() {
return new DataFlavor[] {localObjectFlavor};
}
@Override public boolean isDataFlavorSupported(DataFlavor flavor) {
return Objects.equals(localObjectFlavor, flavor);
}
@Override public Object getTransferData(DataFlavor flavor)
throws UnsupportedFlavorException, IOException {
if (isDataFlavorSupported(flavor)) {
return transferedObjects;
} else {
throw new UnsupportedFlavorException(flavor);
}
}
};
}
@Override
public boolean canImport(TransferSupport info) {
return info.isDrop() && info.isDataFlavorSupported(localObjectFlavor);
}
@Override
public int getSourceActions(JComponent c) {
Component glassPane = c.getRootPane().getGlassPane();
glassPane.setCursor(DragSource.DefaultMoveDrop);
return MOVE; // COPY_OR_MOVE;
}
@SuppressWarnings("unchecked")
@Override
public boolean importData(TransferSupport info) {
TransferHandler.DropLocation tdl = info.getDropLocation();
if (!canImport(info) || !(tdl instanceof JList.DropLocation)) {
return false;
}
JList.DropLocation dl = (JList.DropLocation) tdl;
JList target = (JList) info.getComponent();
DefaultListModel listModel = (DefaultListModel) target.getModel();
int max = listModel.getSize();
int index = dl.getIndex();
index = index < 0 ? max : index; // If it is out of range, it is appended to the end
index = Math.min(index, max);
addIndex = index;
try {
Object[] values = (Object[]) info.getTransferable().getTransferData(localObjectFlavor);
for (int i = 0; i < values.length; i++) {
int idx = index++;
listModel.add(idx, values[i]);
target.addSelectionInterval(idx, idx);
}
addCount = values.length;
return true;
} catch (UnsupportedFlavorException | IOException ex) {
ex.printStackTrace();
}
return false;
}
@Override
protected void exportDone(JComponent c, Transferable data, int action) {
c.getRootPane().getGlassPane().setVisible(false);
cleanup(c, action == MOVE);
}
private void cleanup(JComponent c, boolean remove) {
if (remove && Objects.nonNull(indices)) {
if (addCount > 0) {
// https://github.com/aterai/java-swing-tips/blob/master/DragSelectDropReordering/src/java/example/MainPanel.java
for (int i = 0; i < indices.length; i++) {
if (indices[i] >= addIndex) {
indices[i] += addCount;
}
}
}
JList source = (JList) c;
DefaultListModel model = (DefaultListModel) source.getModel();
for (int i = indices.length - 1; i >= 0; i--) {
model.remove(indices[i]);
}
}
indices = null;
addCount = 0;
addIndex = -1;
}
}
导入java.awt.BorderLayout;
导入java.awt.Component;
导入java.awt.EventQueue;
导入java.awt.datatransfer.DataFlavor;
导入java.awt.datatransfer.transfer;
导入java.awt.datatransfer.UnsupportedFlavorException;
导入java.awt.dnd.DragSource;
导入java.io.IOException;
导入java.io.Serializable;
导入java.util.array;
导入java.util.Objects;
//导入javax.activation.ActivationDataFlavor;
//导入javax.activation.DataHandler;
导入javax.swing.BorderFactory;
导入javax.swing.DefaultListModel;
导入javax.swing.DropMode;
导入javax.swing.Icon;
导入javax.swing.JComponent;
导入javax.swing.JFrame;
导入javax.swing.JLabel;
导入javax.swing.JList;
导入javax.swing.JPanel;
导入javax.swing.JScrollPane;
导入javax.swing.ListCellRenderer;
导入javax.swing.ListSelectionModel;
导入javax.swing.TransferHandler;
导入javax.swing.UIManager;
导入javax.swing.WindowConstants;
公共类DragAndDropTest{
公共JComponent makeUI(){
DefaultListModel m=新的DefaultListModel();
对于(字符串s:Arrays.asList(“错误”、“信息”、“问题”、“警告”)){
m、 添加元素(新缩略图);
}
JList列表=新JList(m);
list.getSelectionModel().setSelectionMode(
ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);
setTransferHandler(新的ListItemTransferHandler());
list.setDropMode(DropMode.INSERT);
list.setDragEnabled(true);
// https://java-swing-tips.blogspot.com/2008/10/rubber-band-selection-drag-and-drop.html
list.setLayoutOrientation(JList.HORIZONTAL_WRAP);
list.setVisibleRowCount(0);
列表。设置固定单元格宽度(80);
列表。设置固定单元高度(80);
list.setboorder(BorderFactory.createEmptyBorder(10,10,10,10));
setCellRenderer(新的ListCellRenderer(){
private final JPanel p=new JPanel(new BorderLayout());
私有最终JLabel图标=新JLabel((图标)null,JLabel.CENTER);
专用最终JLabel标签=新的JLabel(“,JLabel.CENTER);
@凌驾
公共组件GetListCellRenderComponent(
JList正如OP在对原始问题的编辑中所指出的,给出的示例中的问题是有两个传输处理程序,并且正如他们在回答中正确指出的,Java教程中有一个示例可以工作
Java教程中的示例的问题是,当使用DropMode.INSERT
并将当前JList
中的项目移动到所选索引之前时,该项目是重复的。这将删除JList
中的项目,并将该项目的副本放在所选位置
import java.awt.EventQueue;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.StringSelection;
import java.awt.datatransfer.Transferable;
import java.awt.datatransfer.UnsupportedFlavorException;
import java.io.IOException;
import javax.swing.DefaultListModel;
import javax.swing.DropMode;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JList;
import javax.swing.JScrollPane;
import javax.swing.ListSelectionModel;
import javax.swing.TransferHandler;
@SuppressWarnings("serial")
public class GUI extends JFrame {
protected GUI() {
super("Simple Rearrangeable List");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
createPanel();
setBounds(10, 10, 350, 500);
setVisible(true);
}
private void createPanel() {
DefaultListModel<String> strings = new DefaultListModel<String>();
for(int i = 1; i <= 100; i++) {
strings.addElement("Item " + i);
}
JList<String> dndList = new JList<String>(strings);
dndList.setDragEnabled(true);
dndList.setDropMode(DropMode.INSERT);
dndList.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
dndList.setTransferHandler(new TransferHandler() {
private int index;
private boolean beforeIndex = false; //Start with `false` therefore if it is removed from or added to the list it still works
@Override
public int getSourceActions(JComponent comp) {
return MOVE;
}
@Override
public Transferable createTransferable(JComponent comp) {
index = dndList.getSelectedIndex();
return new StringSelection(dndList.getSelectedValue());
}
@Override
public void exportDone(JComponent comp, Transferable trans, int action) {
if (action == MOVE) {
if(beforeIndex)
strings.remove(index + 1);
else
strings.remove(index);
}
}
@Override
public boolean canImport(TransferHandler.TransferSupport support) {
return support.isDataFlavorSupported(DataFlavor.stringFlavor);
}
@Override
public boolean importData(TransferHandler.TransferSupport support) {
try {
String s = (String) support.getTransferable().getTransferData(DataFlavor.stringFlavor);
JList.DropLocation dl = (JList.DropLocation) support.getDropLocation();
strings.add(dl.getIndex(), s);
beforeIndex = dl.getIndex() < index ? true : false;
return true;
} catch (UnsupportedFlavorException | IOException e) {
e.printStackTrace();
}
return false;
}
});
JScrollPane scrollPane = new JScrollPane(dndList);
getContentPane().add(scrollPane);
}
public static void main(String[] args) {
EventQueue.invokeLater(() -> new GUI());
}
}