Java JList上Transferable和Transferhandler的自定义删除容器
在过去的一周里，我试图解决这个问题，但不知何故，我似乎找不到解决办法。关于这个主题的信息不多，因此很难找到示例或代码来查看 我这里有一个JList，它使用自定义TransferHandler创建自定义TransferHandler，以下是相关类的代码供参考： 可转让：Java JList上Transferable和Transferhandler的自定义删除容器,java,swing,jlist,transferable,Java,Swing,Jlist,Transferable,在过去的一周里，我试图解决这个问题，但不知何故，我似乎找不到解决办法。关于这个主题的信息不多，因此很难找到示例或代码来查看 我这里有一个JList，它使用自定义TransferHandler创建自定义TransferHandler，以下是相关类的代码供参考： 可转让： package org.dinhware.swing.special; import java.awt.datatransfer.DataFlavor; import java.awt.datatransfer.Transfer
package org.dinhware.swing.special;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.Transferable;
import java.awt.datatransfer.UnsupportedFlavorException;
import java.io.IOException;
/**
* Created by: Niklas
* Date: 20.10.2017
* Alias: Dinh
* Time: 20:03
*/
public class GenericTransferable<T> implements Transferable {
static DataFlavor FLAVOR;
private T object;
GenericTransferable(T object) {
GenericTransferable.FLAVOR = new DataFlavor(object.getClass(), object.getClass().getCanonicalName());
this.object = object;
}
@Override
public DataFlavor[] getTransferDataFlavors() {
return new DataFlavor[]{FLAVOR};
}
@Override
public boolean isDataFlavorSupported(DataFlavor flavor) {
return flavor.equals(FLAVOR);
}
@Override
public Object getTransferData(DataFlavor flavor) throws UnsupportedFlavorException, IOException {
return object;
}
}
bin=info.getComponent（）实例，我认为这应该可以工作。但这一领域始终是错误的。我继续，并为它添加了一个日志
System.out.println("IMPORT");
if (info.getComponent() instanceof HBin) {
System.out.println("bin");
return bin = true;
}
它最终打印了导入，然后是bin。在调用importData exportData之后，我在其中记录了bin的值，无论出于何种原因，该值现在再次为false。同时，moveAllowed字段似乎发生了变化
这是我的完全修改的TransferHandler
package org.dinhware.swing.special;
import org.dinhware.swing.child.HBin;
import javax.swing.*;
import java.awt.datatransfer.Transferable;
import java.awt.datatransfer.UnsupportedFlavorException;
import java.io.IOException;
/**
* Created by: Niklas Date: 19.10.2017 Alias: Dinh Time: 18:54
*/
@SuppressWarnings("unchecked")
public class HListItemTransferHandler<T> extends TransferHandler {
@Override
protected Transferable createTransferable(JComponent component) {
System.out.println("CREATE");
JList<T> list = (JList<T>) component;
index = list.getSelectedIndex();
T transferredObject = list.getSelectedValue();
return new GenericTransferable<>(transferredObject);
}
@Override
public boolean canImport(TransferSupport info) {
return info.isDataFlavorSupported(GenericTransferable.FLAVOR);
}
@Override
public int getSourceActions(JComponent c) {
System.out.println("ACTION");
return MOVE;
}
@Override
public boolean importData(TransferSupport info) {
System.out.println("IMPORT");
if (!canImport(info)) {
return false;
}
if (info.getComponent() instanceof HBin) {
System.out.println("bin");
return bin = true;
}
JList<Object> target = (JList<Object>) info.getComponent();
JList.DropLocation dl = (JList.DropLocation) info.getDropLocation();
DefaultListModel<Object> listModel = (DefaultListModel<Object>) target.getModel();
int index = dl.getIndex();
int max = listModel.getSize();
if (index < 0 || index > max)
index = max;
addIndex = index;
try {
Object object = info.getTransferable().getTransferData(GenericTransferable.FLAVOR);
listModel.add(index, object);
target.addSelectionInterval(index, index);
return moveAllowed = true;
} catch (UnsupportedFlavorException | IOException e) {
e.printStackTrace();
}
return false;
}
@Override
protected void exportDone(JComponent c, Transferable data, int action) {
System.out.println("EXPORT " + moveAllowed + "/" + bin);
if (moveAllowed)
cleanup(c, action == MOVE, false);
else
cleanup(c, true, true);
}
private void cleanup(JComponent component, boolean remove, boolean bin) {
System.out.println("CLEAN");
if (remove && index != -1) {
JList<T> source = (JList<T>) component;
DefaultListModel<T> model = (DefaultListModel<T>) source.getModel();
int removeAt = index > addIndex ? index + 1 : index;
model.remove(bin ? removeAt - 1 : removeAt);
}
index = -1;
addIndex = -1;
moveAllowed = false;
}
private int index = -1;
private int addIndex = -1;
private boolean moveAllowed = false, bin = false;
}
但是当落在HBin集装箱上时，我无法解释发生了什么（打印）
我确信这应该是假的/真的
现在我被卡住了，无法使容器仅在掉落到HBin上时消失，同时也对字段值没有改变感到困惑，因为它清楚地记录到它已设置为true
请。。帮助…拖放操作很复杂，至少有两种方法可以做到这一点
D'n'D围绕着将一个对象“包装”在一个“可转移”的包中的想法展开，该包可以通过多种不同的方式“导入”（即DataFlavor
s）
因此，在本例中，我只关注从JList
中删除项目，为此，我创建了一个Trash
对象，它实际上维护了对要删除项目的引用（我还创建了一个ListTrash
对象，以演示至少一种传递更多信息的方法）
当在JList
拥有Trash
对象的主要原因是，它允许标准化DataFlavor
。“垃圾桶”只关心垃圾
对象，其他什么都不关心。如果有更多的TransferHandler执行更多操作，这一点尤其重要
我做的另一件事是创建两个TransferHandler
s。一个用于“垃圾桶”，另一个用于JList
，其主要原因是它隔离了每个处理程序想要执行的功能，并降低了复杂性，因为您不需要确定哪个对象正在尝试执行哪个操作
该示例还有另一个组件，它根本做不了什么，因此它可以拒绝删除操作
如果您有另一个组件使用TransferHandler
s，那么这些组件需要拒绝TrashTransferable.FLAVOR
import java.awt.Dimension;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.Transferable;
import java.awt.datatransfer.UnsupportedFlavorException;
import java.awt.dnd.DnDConstants;
import java.io.IOException;
import javax.swing.DefaultListModel;
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.SwingUtilities;
import javax.swing.TransferHandler;
import javax.swing.TransferHandler.TransferSupport;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
JFrame frame = new JFrame("Test");
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
public TestPane() {
setLayout(new GridBagLayout());
DefaultListModel<String> model = new DefaultListModel<>();
model.addElement("Cooks_Assistant");
model.addElement("Romeo_and_Juliet");
model.addElement("Sheep_Shearer");
JList list = new JList(model);
list.setTransferHandler(new HListItemTransferHandler());
list.setDragEnabled(true);
JLabel noDrop = new JLabel("No drop here", JLabel.CENTER);
JLabel trash = new JLabel("All your trash belong to us", JLabel.CENTER);
trash.setTransferHandler(new BinTransferHandler());
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridx = 0;
gbc.gridy = 0;
gbc.weightx = 0.5;
gbc.weighty = 1;
gbc.fill = GridBagConstraints.BOTH;
gbc.insets = new Insets(4, 4, 4, 4);
add(new JScrollPane(list), gbc);
gbc.gridx++;
add(noDrop, gbc);
gbc.gridx = 0;
gbc.gridy++;
gbc.gridwidth = GridBagConstraints.REMAINDER;
add(trash, gbc);
}
@Override
public Dimension getPreferredSize() {
return new Dimension(300, 300);
}
}
public class BinTransferHandler extends TransferHandler {
@Override
public boolean canImport(TransferSupport info) {
return info.isDataFlavorSupported(TrashTransferable.FLAVOR);
}
@Override
public int getSourceActions(JComponent c) {
System.out.println("ACTION");
return DnDConstants.ACTION_MOVE;
}
@Override
public boolean importData(TransferSupport support) {
if (!canImport(support)) {
return false;
}
// Check target component
Transferable transferable = support.getTransferable();
try {
Trash trash = (Trash) transferable.getTransferData(TrashTransferable.FLAVOR);
Object item = trash.getItem();
System.out.println(">> Trash " + item);
return true;
} catch (UnsupportedFlavorException | IOException ex) {
ex.printStackTrace();
}
return false;
}
}
public class HListItemTransferHandler<T> extends TransferHandler {
@Override
protected Transferable createTransferable(JComponent component) {
System.out.println("createTransferable");
JList<T> list = (JList<T>) component;
int index = list.getSelectedIndex();
T transferredObject = list.getSelectedValue();
return new TrashTransferable(new ListTrash<>(list, index, transferredObject));
}
@Override
public boolean canImport(TransferSupport info) {
return info.isDataFlavorSupported(TrashTransferable.FLAVOR);
}
@Override
public int getSourceActions(JComponent c) {
return DnDConstants.ACTION_MOVE;
}
@Override
public boolean importData(TransferSupport info) {
JList<Object> target = (JList<Object>) info.getComponent();
JList.DropLocation dl = (JList.DropLocation) info.getDropLocation();
DefaultListModel<Object> listModel = (DefaultListModel<Object>) target.getModel();
int index = dl.getIndex();
int max = listModel.getSize();
if (index < 0 || index > max) {
index = max;
}
try {
Object object = info.getTransferable().getTransferData(DataFlavor.stringFlavor);
listModel.add(index, object);
target.addSelectionInterval(index, index);
return true;
} catch (UnsupportedFlavorException | IOException e) {
e.printStackTrace();
}
return false;
}
@Override
protected void exportDone(JComponent c, Transferable data, int action) {
System.out.println("Export data");
try {
if (action != MOVE) {
return;
}
if (!(c instanceof JList)) {
return;
}
JList list = (JList) c;
if (!(list.getModel() instanceof DefaultListModel)) {
return;
}
DefaultListModel model = (DefaultListModel) list.getModel();
if (!(data instanceof TrashTransferable)) {
return;
}
Object transferData = data.getTransferData(TrashTransferable.FLAVOR);
if (transferData == null || !(transferData instanceof Trash)) {
return;
}
Trash trash = (Trash) transferData;
Object item = trash.item;
int index = model.indexOf(item);
if (index == -1) {
return;
}
model.remove(index);
} catch (UnsupportedFlavorException | IOException ex) {
ex.printStackTrace();
}
}
}
public static class ListTrash<T> extends Trash<T> {
private JList list;
private int index;
public ListTrash(JList list, int index, T item) {
super(item);
this.list = list;
this.index = index;
}
public JList getList() {
return list;
}
public int getIndex() {
return index;
}
}
public static class Trash<T> {
private T item;
public Trash(T item) {
this.item = item;
}
public T getItem() {
return item;
}
}
public static class TrashTransferable<T> implements Transferable {
public static final DataFlavor FLAVOR = new DataFlavor(Trash.class, "Trash");
private Trash<T> trash;
TrashTransferable(Trash<T> object) {
trash = object;
}
@Override
public DataFlavor[] getTransferDataFlavors() {
return new DataFlavor[]{FLAVOR};
}
@Override
public boolean isDataFlavorSupported(DataFlavor flavor) {
return flavor.equals(flavor);
}
@Override
public Object getTransferData(DataFlavor flavor) throws UnsupportedFlavorException, IOException {
return trash;
}
}
}
导入java.awt.Dimension；
导入java.awt.GridBagConstraints；
导入java.awt.GridBagLayout；
导入java.awt.Insets；
导入java.awt.datatransfer.DataFlavor；
导入java.awt.datatransfer.transfer；
导入java.awt.datatransfer.UnsupportedFlavorException；
导入java.awt.dnd.DnDConstants；
导入java.io.IOException；
导入javax.swing.DefaultListModel；
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.SwingUtilities；
导入javax.swing.TransferHandler；
导入javax.swing.TransferHandler.TransferSupport；
公开课考试{
公共静态void main（字符串[]args）{
新测试（）；
}
公开考试（）{
SwingUtilities.invokeLater（新的Runnable（）{
@凌驾
公开募捐{
JFrame=新JFrame（“测试”）；
frame.add（newtestpane（））；
frame.pack（）；
frame.setLocationRelativeTo（空）；
frame.setVisible（true）；
}
});
}
公共类TestPane扩展了JPanel{
公共测试窗格（）{
setLayout（新的GridBagLayout（））；
DefaultListModel=新的DefaultListModel（）；
模型.附录（“厨师助理”）；
模型补遗（“罗密欧与朱丽叶”）；
型号.附加件（“剪羊毛机”）；
JList列表=新的JList（型号）；
setTransferHandler（新的HListItemTransferHandler（））；
list.setDragEnabled（true）；
JLabel noDrop=新的JLabel（“此处无下降”，JLabel.CENTER）；
JLabel trash=新JLabel（“您所有的垃圾都属于我们”，JLabel.CENTER）；
setTransferHandler（新的BinTransferHandler（））；
GridBagConstraints gbc=新的GridBagConstraints（）；
gbc.gridx=0；
gbc.gridy=0；
gbc.weightx=0.5；
gbc.weighty=1；
gbc.fill=GridBagConstraints.BOTH；
gbc.插图=新插图（4,4,4,4）；
添加（新的JScrollPane（列表），gbc）；
gbc.gridx++；
添加（noDrop，gbc）；
gbc.gridx=0；
gbc.gridy++；
gbc.gridwidth=GridBagConstraints.rements；
添加（垃圾，gbc）；
}
@凌驾
公共维度getPreferredSize（）{
返回新维度（300300）；
}
}
公共类BinTransferHandler扩展了TransferHandler{
@凌驾
公共布尔ca
System.out.println("IMPORT");
if (info.getComponent() instanceof HBin) {
System.out.println("bin");
return bin = true;
}
package org.dinhware.swing.special;
import org.dinhware.swing.child.HBin;
import javax.swing.*;
import java.awt.datatransfer.Transferable;
import java.awt.datatransfer.UnsupportedFlavorException;
import java.io.IOException;
/**
* Created by: Niklas Date: 19.10.2017 Alias: Dinh Time: 18:54
*/
@SuppressWarnings("unchecked")
public class HListItemTransferHandler<T> extends TransferHandler {
@Override
protected Transferable createTransferable(JComponent component) {
System.out.println("CREATE");
JList<T> list = (JList<T>) component;
index = list.getSelectedIndex();
T transferredObject = list.getSelectedValue();
return new GenericTransferable<>(transferredObject);
}
@Override
public boolean canImport(TransferSupport info) {
return info.isDataFlavorSupported(GenericTransferable.FLAVOR);
}
@Override
public int getSourceActions(JComponent c) {
System.out.println("ACTION");
return MOVE;
}
@Override
public boolean importData(TransferSupport info) {
System.out.println("IMPORT");
if (!canImport(info)) {
return false;
}
if (info.getComponent() instanceof HBin) {
System.out.println("bin");
return bin = true;
}
JList<Object> target = (JList<Object>) info.getComponent();
JList.DropLocation dl = (JList.DropLocation) info.getDropLocation();
DefaultListModel<Object> listModel = (DefaultListModel<Object>) target.getModel();
int index = dl.getIndex();
int max = listModel.getSize();
if (index < 0 || index > max)
index = max;
addIndex = index;
try {
Object object = info.getTransferable().getTransferData(GenericTransferable.FLAVOR);
listModel.add(index, object);
target.addSelectionInterval(index, index);
return moveAllowed = true;
} catch (UnsupportedFlavorException | IOException e) {
e.printStackTrace();
}
return false;
}
@Override
protected void exportDone(JComponent c, Transferable data, int action) {
System.out.println("EXPORT " + moveAllowed + "/" + bin);
if (moveAllowed)
cleanup(c, action == MOVE, false);
else
cleanup(c, true, true);
}
private void cleanup(JComponent component, boolean remove, boolean bin) {
System.out.println("CLEAN");
if (remove && index != -1) {
JList<T> source = (JList<T>) component;
DefaultListModel<T> model = (DefaultListModel<T>) source.getModel();
int removeAt = index > addIndex ? index + 1 : index;
model.remove(bin ? removeAt - 1 : removeAt);
}
index = -1;
addIndex = -1;
moveAllowed = false;
}
private int index = -1;
private int addIndex = -1;
private boolean moveAllowed = false, bin = false;
}
ACTION
CREATE
IMPORT
EXPORT true/false
CLEAN
ACTION
CREATE
IMPORT
bin
EXPORT false/false
import java.awt.Dimension;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.Transferable;
import java.awt.datatransfer.UnsupportedFlavorException;
import java.awt.dnd.DnDConstants;
import java.io.IOException;
import javax.swing.DefaultListModel;
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.SwingUtilities;
import javax.swing.TransferHandler;
import javax.swing.TransferHandler.TransferSupport;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
JFrame frame = new JFrame("Test");
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
public TestPane() {
setLayout(new GridBagLayout());
DefaultListModel<String> model = new DefaultListModel<>();
model.addElement("Cooks_Assistant");
model.addElement("Romeo_and_Juliet");
model.addElement("Sheep_Shearer");
JList list = new JList(model);
list.setTransferHandler(new HListItemTransferHandler());
list.setDragEnabled(true);
JLabel noDrop = new JLabel("No drop here", JLabel.CENTER);
JLabel trash = new JLabel("All your trash belong to us", JLabel.CENTER);
trash.setTransferHandler(new BinTransferHandler());
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridx = 0;
gbc.gridy = 0;
gbc.weightx = 0.5;
gbc.weighty = 1;
gbc.fill = GridBagConstraints.BOTH;
gbc.insets = new Insets(4, 4, 4, 4);
add(new JScrollPane(list), gbc);
gbc.gridx++;
add(noDrop, gbc);
gbc.gridx = 0;
gbc.gridy++;
gbc.gridwidth = GridBagConstraints.REMAINDER;
add(trash, gbc);
}
@Override
public Dimension getPreferredSize() {
return new Dimension(300, 300);
}
}
public class BinTransferHandler extends TransferHandler {
@Override
public boolean canImport(TransferSupport info) {
return info.isDataFlavorSupported(TrashTransferable.FLAVOR);
}
@Override
public int getSourceActions(JComponent c) {
System.out.println("ACTION");
return DnDConstants.ACTION_MOVE;
}
@Override
public boolean importData(TransferSupport support) {
if (!canImport(support)) {
return false;
}
// Check target component
Transferable transferable = support.getTransferable();
try {
Trash trash = (Trash) transferable.getTransferData(TrashTransferable.FLAVOR);
Object item = trash.getItem();
System.out.println(">> Trash " + item);
return true;
} catch (UnsupportedFlavorException | IOException ex) {
ex.printStackTrace();
}
return false;
}
}
public class HListItemTransferHandler<T> extends TransferHandler {
@Override
protected Transferable createTransferable(JComponent component) {
System.out.println("createTransferable");
JList<T> list = (JList<T>) component;
int index = list.getSelectedIndex();
T transferredObject = list.getSelectedValue();
return new TrashTransferable(new ListTrash<>(list, index, transferredObject));
}
@Override
public boolean canImport(TransferSupport info) {
return info.isDataFlavorSupported(TrashTransferable.FLAVOR);
}
@Override
public int getSourceActions(JComponent c) {
return DnDConstants.ACTION_MOVE;
}
@Override
public boolean importData(TransferSupport info) {
JList<Object> target = (JList<Object>) info.getComponent();
JList.DropLocation dl = (JList.DropLocation) info.getDropLocation();
DefaultListModel<Object> listModel = (DefaultListModel<Object>) target.getModel();
int index = dl.getIndex();
int max = listModel.getSize();
if (index < 0 || index > max) {
index = max;
}
try {
Object object = info.getTransferable().getTransferData(DataFlavor.stringFlavor);
listModel.add(index, object);
target.addSelectionInterval(index, index);
return true;
} catch (UnsupportedFlavorException | IOException e) {
e.printStackTrace();
}
return false;
}
@Override
protected void exportDone(JComponent c, Transferable data, int action) {
System.out.println("Export data");
try {
if (action != MOVE) {
return;
}
if (!(c instanceof JList)) {
return;
}
JList list = (JList) c;
if (!(list.getModel() instanceof DefaultListModel)) {
return;
}
DefaultListModel model = (DefaultListModel) list.getModel();
if (!(data instanceof TrashTransferable)) {
return;
}
Object transferData = data.getTransferData(TrashTransferable.FLAVOR);
if (transferData == null || !(transferData instanceof Trash)) {
return;
}
Trash trash = (Trash) transferData;
Object item = trash.item;
int index = model.indexOf(item);
if (index == -1) {
return;
}
model.remove(index);
} catch (UnsupportedFlavorException | IOException ex) {
ex.printStackTrace();
}
}
}
public static class ListTrash<T> extends Trash<T> {
private JList list;
private int index;
public ListTrash(JList list, int index, T item) {
super(item);
this.list = list;
this.index = index;
}
public JList getList() {
return list;
}
public int getIndex() {
return index;
}
}
public static class Trash<T> {
private T item;
public Trash(T item) {
this.item = item;
}
public T getItem() {
return item;
}
}
public static class TrashTransferable<T> implements Transferable {
public static final DataFlavor FLAVOR = new DataFlavor(Trash.class, "Trash");
private Trash<T> trash;
TrashTransferable(Trash<T> object) {
trash = object;
}
@Override
public DataFlavor[] getTransferDataFlavors() {
return new DataFlavor[]{FLAVOR};
}
@Override
public boolean isDataFlavorSupported(DataFlavor flavor) {
return flavor.equals(flavor);
}
@Override
public Object getTransferData(DataFlavor flavor) throws UnsupportedFlavorException, IOException {
return trash;
}
}
}