【Java】JList笔记

 

 

Table of Contents

• 1 JList
• 2 构造函数
• 3 ListMode
  • 3.1 DefaultListMode
    • 3.1.1 addElement(E element)
    • 3.1.2 add(int index, E element)
• 4 JList 几个函数
  • 4.1 getSelectedValues()
  • 4.2 getSelectedIndices()
• 5 addListSelectionListener(ListSelectionListener)
  • 5.1 ListSelectionListener
  • 5.2 valueChanged(ListSelectionEvent e)
• 6 程序示例

1 JList

与ComboBox不同的是JList把所有的可选项都可见，而ComboBox把所有Item隐藏等待用户下拉后才看见。
原型是JList<E>，是个容器，

2 构造函数

 

JList()
Constructs a JList with an empty, read-only, model.
JList(E[] listData)
Constructs a JList that displays the elements in the specified array.
JList(ListModel<E> dataModel)
Constructs a JList that displays elements from the specified, non-null, model.
JList(Vector<? extends E> listData)
Constructs a JList that displays the elements in the specified Vector.

3 ListMode

This interface defines the methods components like JList use to get the value of each cell in a list and the length of the list. Logically the model is a vector, indices vary from 0 to ListDataModel.getSize() - 1.

3.1 DefaultListMode

 

3.1.1 addElement(E element)

添加元素

3.1.2 add(int index, E element)

在指定位置插入指定元素。

4 JList 几个函数

 

4.1 getSelectedValues()

获取所选元素的值

4.2 getSelectedIndices()

获取所选元素的索引

5 addListSelectionListener(ListSelectionListener)

 

5.1 ListSelectionListener

有Item选中时发生事件

5.2 valueChanged(ListSelectionEvent e)

 

6 程序示例

 

package xjtu.vf.swing;
import java.awt.Color;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.BorderFactory;
import javax.swing.DefaultListModel;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JList;
import javax.swing.JTextArea;
import javax.swing.border.Border;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;
public class List extends JFrame {
    private String[] flavors = { "A", "B", "C", "D", "E", "F" };
    private DefaultListModel lItems = new DefaultListModel();
    private JList lst = new JList(lItems);
    private JTextArea t = new JTextArea(flavors.length, 20);
    private JButton b = new JButton("Add Item");
    private ActionListener bl = new ActionListener() {
        public void actionPerformed(ActionEvent e) {
            if (count < flavors.length)
                lItems.add(0, flavors[count++]);
            else
                b.setEnabled(false);
        }
    };
    private ListSelectionListener lsl = new ListSelectionListener() {
        @SuppressWarnings("deprecation")
        public void valueChanged(ListSelectionEvent e) {
            if (e.getValueIsAdjusting())
                return;
            t.setText("");
            for (Object item : lst.getSelectedValues())
                t.append(item + "\n");
        }
    };
    private int count = 0;
    public List() {
        t.setEditable(true);
        setLayout(new FlowLayout());
        Border brd = BorderFactory.createMatteBorder(1, 1, 2, 2, Color.black);
        lst.setBorder(brd);
        t.setBorder(brd);
        for (int i = 0; i < 4; i++)
            lItems.addElement(flavors[count++]);
        add(t);
        add(lst);
        add(b);
        b.addActionListener(bl);
        lst.addListSelectionListener(lsl);
    }
    public static void main(String[] args) {
        SwingConsole.run(new List(), 250, 375);
    }
}

Author: visaya fan <visayafan[AT]gmail.com>

Date: 2011-11-20 23:49:33

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