我想遍历 TreeMap 以将对象添加到 DefaultListModel，然后添加到 JList。但是，列表中只显示键值，而不显示对象。我该如何纠正？
见下面的代码：
public class ViewInventoryInterface extends JFrame {
private Inventory theInventory; // reference to back end
private InventoryUPCIterator iter;
private DefaultListModel dlm;
private JList list;
private JScrollPane scroll;
public ViewInventoryInterface(Inventory theInventory) {
this.theInventory = theInventory;
iter = theInventory.inventoryUPCIterator(); //returns an iterator for the inventory
dlm = new DefaultListModel();
while (iter.hasNext()) {
dlm.addElement(iter.next());
}
list = new JList(dlm);
scroll = new JScrollPane(list);
setTitle("Inventory");
add(scroll);
setSize(400, 400);
setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
setLocationRelativeTo(null);
setVisible(true);
}
}
这是创建迭代器的类
公共类 InventoryUPCIterator {
private Set<String> keys;
private Iterator<String> iter;
public InventoryUPCIterator(HashMap<String, ItemIndex> inventory) {
TreeMap<String, ItemIndex> values = new TreeMap<String, ItemIndex>(
inventory);
// sorts the index according to the natural ordering of String values
keys = values.keySet();// returns set of sorted keys
iter = keys.iterator();
}
public boolean hasNext() {
return iter.hasNext();
}
public String next() {
return iter.next();
}
public void reset() {
iter = keys.iterator();// start again from the beginning
}
}