[英]JList DefaultListModel ListSelectionListener
我在JSplitPane中有2個DefaultListModels。 JSplitPane的左側具有RssChannel標題。 當選擇了RssChannel標題時,RssItem標題應該顯示在JSplitPane的右側。
選擇初始時間RssChannel標題后,將顯示正確的RssItem標題。 但是,當我在RssChannel標題之間來回切換時,不會觸發正確的RssItem標題。
如何修復我的偵聽器,以便始終從各自的RssChannel觸發正確的RssItem標題?
感謝您的任何建議
import javax.swing.*;
import javax.swing.event.*;
import java.awt.*;
import java.awt.event.*;
import java.util.List;
import java.util.ArrayList;
import java.io.*;
public class GuiDriver extends JFrame{
JList channelTitleList, itemTitleList;
DefaultListModel cModel, iModel;
List<RssReader> feedList = new ArrayList<RssReader>();
int nextFeed=0;
public GuiDriver(){
}
public void addFeed(RssReader feed){
feedList.add(feed);
}
public JToolBar createToolBar(){
JToolBar bar = new JToolBar();
Action newToolBarButton = new AddAction("New");
Action deleteToolBarButton = new RemoveAction("Delete");
Action clearToolBarButton = new ClearAction("Clear");
bar.add(newToolBarButton);
bar.add(deleteToolBarButton);
bar.add(clearToolBarButton);
bar.setFloatable(false);
return bar;
}
public JSplitPane createJSplitPane(){
JSplitPane hSplitPane = new JSpli tPane(JSplitPane.HORIZONTAL_SPLIT,createChannelJScrollPane(), createItemJScrollPane());
hSplitPane.setDividerLocation(500);
return hSplitPane;
}
public JScrollPane createChannelJScrollPane(){
cModel = new DefaultListModel();
channelTitleList = new JList(cModel);
JScrollPane channelJScrollPane = new JScrollPane(channelTitleList);
channelTitleList.setVisibleRowCount(20);
channelTitleList.getSelectionModel.addListSelectionListener(new ChannelListListener());
return channelJScrollPane;
}
public JScrollPane createItemJScrollPane(){
iModel = new DefaultListModel();
itemTitleList = new JList(iModel);
JScrollPane itemJScrollPane = new JScrollPane(itemTitleList);
return itemJScrollPane;
}
public class AddAction extends AbstractAction{
public AddAction(String name){
super(name);
}
public void actionPerformed(ActionEvent e){
System.out.println(getValue(Action.NAME)+" selected.");
JOptionPane message = new JOptionPane();
String firstInput = message.showInputDialog(null, "Enter URL");
try{
DumpStockPage.readXml(firstInput);
File f = new File("RSSFeed.xml");
addFeed(new RssReader(f));
cModel.addElement(feedList.get(nextFeed).rssChannel.getTitle());
nextFeed++;
iModel.clear();
}
catch (IOException ee){
System.err.println(ee);
}
}
}
public class RemoveAction extends AbstractAction{
public RemoveAction(String name){
super(name);
}
public void actionPerformed(ActionEvent e){
cModel.removeElement(channelTitleList.getSelectedValue());
feedList.remove(e);
iModel.clear();
}
}
public class ClearAction extends AbstractAction{
public ClearAction(String name){
super(name);
}
public void actionPerformed(ActionEvent e){
iModel.clear();
}
}
private class ChannelListListener implements ListSelectionListener {
public void valueChanged (ListSelectionEvent e) {
boolean adjust = e.getValueIsAdjusting();
if (!adjust) {
int i = e.getLastIndex();
for (int j=0; j<feedList.get(i).rssChannel.getItems().size(); j++)
iModel.addElement(feedList.get(i).rssChannel.items.get(j).getTitle());
}
}
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
GuiDriver frame = new GuiDriver();
frame.setTitle("RSS Reader");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(frame.createJSplitPane(), BorderLayout.NORTH);
frame.add(frame.createToolBar(), BorderLayout.SOUTH);
frame.setVisible(true);
frame.setSize(800,400);
}
});
}
}
我不確定RssReader的實現,但是您的ChannelListListener
會不斷向您的項目列表添加數據。 您需要的是channelTitleList
所選項目的標題列表。 使用JList
getSelectedIndex()
獲取選定的索引。 接下來,根據所選的提要,構建itemTitleList
的內容,例如以字符串列表的形式。 這是ChannelListListener
入門的示例:
public void valueChanged (ListSelectionEvent e) {
boolean adjust = e.getValueIsAdjusting();
if (!adjust) {
List<String> titles = new ArrayList<String>();
int i = channelTitleList.getSelectedIndex(); //the index of the selected item in the left list
//Change RssFeed to the appropriate class for these 'items'
for(RssFeed feed: feedList.get(i).rssChannel.items) {
titles.add(feed.getTitle()); //build a list of titles, to be shown in the right list
}
itemTitleList.setListData(titles.toArray()); //change the content of the right list
}
}
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