我必须与JLists合作完成一个项目,我不得不尝试做一些事情。 这是我的清单:
JList<String> BooksList = new JList<String>(booksList);
books.add(BooksList, BorderLayout.CENTER);
BooksList.setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);
JList cartList = new JList();
cart.add(cartList, BorderLayout.CENTER);
cartList.setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);
在BooksList中有以下项目:
I Did It Your Way;11.95
The History of Scotland;14.50
Learn Calculus in One Day;29.95
Feel the Stress;18.50
Great Poems;12.95
Europe on a Shoestring;10.95
The Life of Mozart;14.50
1。)将项目从BooksList移动到cartList,具体来说我需要它来附加新添加的项目,但如果我尝试一次添加一个项目,那么它将用新项目替换cartList中已有的项目。这是我的代码:
//Adding To Cart
JButton AddToCart = new JButton("Add To Cart");
AddToCart.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
ArrayList<String> selectionList = (ArrayList<String>) BooksList.getSelectedValuesList();
Object[] selections = selectionList.toArray();
cartList.setListData(selections);
}
});
AddToCart.setToolTipText("Alt + A For Auto Add");
AddToCart.setBounds(264, 178, 117, 25);
AddToCart.setMnemonic(KeyEvent.VK_A);
frame.getContentPane().add(AddToCart);
2。)清除购物车清单完全由于某种原因,点击后没有任何反应。这是代码:
//This Will Clear The Whole Cart List
JMenuItem Clear = new JMenuItem("Clear Alt + C");
cartMenu.add(Clear);
Clear.setMnemonic(KeyEvent.VK_C);
Clear.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent arg0) {
DefaultListModel tempModel = (DefaultListModel)cartList.getModel();
tempModel.removeAllElements();
}
});
3。)删除所选项目,与2相同,它不做任何事情。我有以下代码:
//Remove A Selected Item From The List
JMenuItem RemoveSelected = new JMenuItem("Remove Selected Alt + R");
cartMenu.add(RemoveSelected);
RemoveSelected.setMnemonic(KeyEvent.VK_R);
RemoveSelected.addActionListener(new ActionListener (){
public void actionPerformed(ActionEvent e) {
DefaultListModel tempModel = (DefaultListModel)cartList.getModel();
int selected = cartList.getSelectedIndex();
if(selected != -1)
{
tempModel.remove(selected);
}
}
});
答案 0 :(得分:4)
当您添加到JList
时,您希望将其添加到ListModel
而非直接添加:
DefaultListModel tempModel = (DefaultListModel) cartList.getModel();
for (String s: BooksList.getSelectedValuesList())
tempModel.addElement(s);
我还没有机会对此进行测试,但这是正确的做法。目前,您正在调用.setListData()
,这会清除其中的内容并替换它。这将为其添加一些内容。
您可能会发现this question有帮助。