JList - 選擇多個項目

Question

當我想在JList自動選擇多個值時，我在JList遇到了這個setSelectedValue()方法的問題，它仍然只選擇了一個。 有辦法嗎？

 String[] items = { "Item 1", "Item 2", "Item 3", "Item 4" };
      final JList theList = new JList(items);
      theList.setSelectedValue("Item 1",true);
      theList.setSelectedValue("Item 2",true);

此代碼僅顯示選定的Item 2 。

Answer 1

在調用JList.setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION)之后使用JList.setSelectedIndices(int[]) JList.setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION) 。

例如

import javax.swing.*;
import java.io.*;
import java.util.ArrayList;
class MultiSelectList {
    public static void main(String[] args) throws Exception {
        File f = new File("MultiSelectList.java");
        InputStream is = new FileInputStream(f);
        InputStreamReader isr = new InputStreamReader(is);
        BufferedReader br = new BufferedReader(isr);
        final ArrayList<String> lines = new ArrayList<String>();
        String line = br.readLine();
        while (line!=null) {
            lines.add(line);
            line = br.readLine();
        }
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                JList list = new JList(lines.toArray());
                list.setSelectionMode(
                    ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);
                int[] select = {19, 20, 22};
                list.setSelectedIndices(select);
                JOptionPane.showMessageDialog(null, new JScrollPane(list));
            }
        });
    }
}

屏幕截圖

Answer 2

list.getSelectionModel().setSelectionInterval(...);

或者如果選擇不連續，則需要使用多個

list.getSelectionModel().addSelectionInterval(...);

Answer 3

在使用NetBeans GUI編輯器時，您可以自定義為JList生成Post-Creation Code ，如下所示。

Answer 4

import javax.swing.*;
import java.io.*;
import java.util.ArrayList;

class MultiSelectList {
    public static void main(String[] args) throws Exception {
        File f = new File("MultiSelectList.java");
        InputStream is = new FileInputStream(f);
        InputStreamReader isr = new InputStreamReader(is);
        BufferedReader br = new BufferedReader(isr);
        final ArrayList<String> lines = new ArrayList<String>();
        String line = br.readLine();
        while (line!=null) {
            lines.add(line);
            line = br.readLine();
        }
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                JList list = new JList(lines.toArray());
                list.setSelectionMode(
                    ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);
                int[] select = {19, 20, 22};
                list.setSelectedIndices(select);
                JOptionPane.showMessageDialog(null, new JScrollPane(list));
            }
        });
    }
}