【发布时间】：2015-11-12 13:39:59
【问题描述】：
每个人。我正在实现拖放 GUI。 我现在想要做的是禁用或启用我的 GUI 上的按钮取决于 Jlist 的组件数量。
这是我的代码
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.UnsupportedFlavorException;
import java.io.File;
import java.io.IOException;
import java.util.List;
import javax.swing.*;
import javax.swing.GroupLayout.Alignment;
import javax.swing.LayoutStyle.ComponentPlacement;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
@SuppressWarnings("serial")
public class FileDragDemo extends JPanel {
private JList list = new JList();
public FileDragDemo() {
list.setDragEnabled(true);
list.setTransferHandler(new FileListTransferHandler(list));
JScrollPane scrollPane = new JScrollPane(list);
JButton btnCompare = new JButton("Compare");
btnCompare.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
}
});
JButton btnAnalyze = new JButton("Analyze");
btnAnalyze.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
}
});
JButton btnRefresh = new JButton("Refresh");
btnRefresh.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
DefaultListModel listModel = (DefaultListModel) list.getModel();
listModel.removeAllElements();
}
});
if (list.getModel().getSize() > 1){
btnAnalyze.setEnabled( false );
}
// if (listModel.getSize() > 1){
// btnAnalyze.setEnabled( false );
// }
GroupLayout groupLayout = new GroupLayout(this);
groupLayout.setHorizontalGroup(
groupLayout.createParallelGroup(Alignment.LEADING)
.addGroup(groupLayout.createSequentialGroup()
.addComponent(scrollPane, GroupLayout.PREFERRED_SIZE, 316, GroupLayout.PREFERRED_SIZE)
.addPreferredGap(ComponentPlacement.RELATED)
.addGroup(groupLayout.createParallelGroup(Alignment.LEADING, false)
.addComponent(btnRefresh, GroupLayout.DEFAULT_SIZE, GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(btnAnalyze, GroupLayout.DEFAULT_SIZE, GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(btnCompare, GroupLayout.DEFAULT_SIZE, GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
.addContainerGap())
);
groupLayout.setVerticalGroup(
groupLayout.createParallelGroup(Alignment.LEADING)
.addComponent(scrollPane, GroupLayout.PREFERRED_SIZE, 144, GroupLayout.PREFERRED_SIZE)
.addGroup(groupLayout.createSequentialGroup()
.addContainerGap()
.addComponent(btnCompare)
.addPreferredGap(ComponentPlacement.RELATED)
.addComponent(btnAnalyze)
.addPreferredGap(ComponentPlacement.RELATED)
.addComponent(btnRefresh))
);
setLayout(groupLayout);
}
private static void createAndShowGui() {
FileDragDemo mainPanel = new FileDragDemo();
JFrame frame = new JFrame("FileDragDemo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
@SuppressWarnings("serial")
class FileListTransferHandler extends TransferHandler {
private JList list;
public FileListTransferHandler(JList list) {
this.list = list;
}
public int getSourceActions(JComponent c) {
return COPY_OR_MOVE;
}
public boolean canImport(TransferSupport ts) {
return ts.isDataFlavorSupported(DataFlavor.javaFileListFlavor);
}
public boolean importData(TransferSupport ts) {
try {
@SuppressWarnings("rawtypes")
List data = (List) ts.getTransferable().getTransferData(
DataFlavor.javaFileListFlavor);
if (data.size() < 1) {
return false;
}
DefaultListModel listModel = new DefaultListModel();
for (Object item : data) {
File file = (File) item;
listModel.addElement(file);
}
list.setModel(listModel);
return true;
} catch (UnsupportedFlavorException e) {
return false;
} catch (IOException e) {
return false;
}
}
}
当Jlist中的拖放元素大于1时，我想禁用btnAnalyze。 此外，当 Jlist 中的拖放元素为 1 时，我想禁用 btnCompare。
请帮帮我。谢谢
【问题讨论】：
-
您能否澄清一下，当只有一个条目并且与比较相同时，您想禁用 btnAnalyze 吗？这很容易做到，只需要更多细节。
-
很抱歉。我想在有 2 个条目启用 btnCompare 时禁用 btnAnalyze，并且我想在有一个条目启用 btnAnalyze 时禁用 btnCompare
标签： java drag-and-drop jbutton jlist