[英]how can I search an item by property in a JList
我有一个项目类,我将项目存储在 JList 中,我想通过项目名称在 JList 中查找项目。 我有一个名为 search 的 JButton,它实现了下一个代码,nameToSearch 变量获取写入 JTextfield 的字符串,
ArrayList<Item> backUp = new ArrayList<>();
ArrayList<Item> itemsFound = new ArrayList<>();
for (int i = 0; i < listModel.getSize(); i++) {
backUp.add(listModel.getElementAt(i));
if (listModel.getElementAt(i).getName().compareToIgnoreCase(nameToSearch) >= 0) {
Item foundItem = listModel.getElementAt(i);
itemsFound.add(foundItem);
}
}
//clear the listModel to display the found items
listModel.removeAllElements();
//add the found items to the listModel to be displayed
for (Item s: itemsFound) {
listModel.addElement(s);}
我的意思是让备份 arrayList 中的所有项目稍后显示所有项目,if 语句检查是 item.getName() 是用户正在寻找的内容,并将该元素添加到 itemfound ArrayList,它是应该在 arrayList 中找到项目,然后我从 defaultListModel listmodel 中删除所有元素,然后将找到的项目添加到 defaultListModel listModel 中,这样找到的项目是当时 JList 上唯一的项目。 但这不起作用,它什么也没做。 非常感谢有关如何做的任何建议
一个非常简单的解决方案可以是:
JList
使用DefaultListModel (以编程方式动态)。例如:
import java.awt.BorderLayout;
import java.util.Arrays;
import java.util.List;
import java.util.Objects;
import javax.swing.DefaultListModel;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextField;
public class Main {
//Assuming the class Item is similar to the following implementation:
public static class Item {
private final String name;
public Item(final String name) {
this.name = Objects.requireNonNull(name);
}
public String getName() {
return name;
}
//Overriding toString method, to avoid implementing a custom ListCellRenderer...
@Override
public String toString() {
return getName();
}
}
public static void main(final String[] args) {
//The following list contains all the initial Items lets say:
final List<Item> allItems = Arrays.asList(new Item("abc"), new Item("ABC"),
new Item("def"), new Item("DEF"));
//Create a DefaultListModelof Items (which is programmatically dynamic):
final DefaultListModel<Item> listModel = new DefaultListModel<>();
//Supply the model to the list on creation time (or later with setModel):
final JList<Item> list = new JList<>(listModel);
//Initialize the listModel to initially contain all items:
allItems.forEach(item -> listModel.addElement(item));
final JTextField searchField = new JTextField(10);
final JButton searchButton = new JButton("Search");
searchButton.addActionListener(e -> {
final String searchText = searchField.getText();
listModel.clear();
if (searchText.isEmpty()) //If the search text field is empty, lets say we want to display all values:
allItems.forEach(item -> listModel.addElement(item));
else
allItems.forEach(item -> {
if (item.getName().equalsIgnoreCase(searchText))
listModel.addElement(item);
});
});
final JPanel pageStart = new JPanel(); //FlowLayout
pageStart.add(searchField);
pageStart.add(searchButton);
final JPanel all = new JPanel(new BorderLayout());
all.add(pageStart, BorderLayout.PAGE_START);
all.add(new JScrollPane(list), BorderLayout.CENTER);
final JFrame frame = new JFrame("Searchable JList");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(all);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
}
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