圖形界面（簡(jiǎn)稱GUI）是指采用圖形方式顯示的計(jì)算機(jī)操作用戶界面。與早期計(jì)算機(jī)使用的命令行界面相比，圖形界面對(duì)于用戶來(lái)說(shuō)在視覺(jué)上更易于接受，本篇精講Java語(yǔ)言中關(guān)于圖形用戶界面的列表框JList

列表框JList

JList常用方法

方法	作用
public JList(ListModel dataModel)	根據(jù)ListModel構(gòu)造JList
public JList(Object[] listData)	根據(jù)對(duì)象數(shù)組構(gòu)造JList
public JList(Vector<?> listData)	根據(jù)一個(gè)Vector構(gòu)造JList
public void setSelectionMode(int selectionMode)	設(shè)置選擇模式，是多選還是單選
public ListModel getModel()	返回列表框的列表模型
public int[] getSelectedIndices()	返回所選擇的全部數(shù)組

可以通過(guò)ListSelectionModel接口完成列表框是多選還是單選

ListSelectionModel定義的常量

常量	作用
static final int MULTIPLE_INTERVAL_SELECTION	一次選擇一個(gè)或多個(gè)連續(xù)的索引范圍
static final int SINGLE_INTERVAL_SELECTION	一次選擇一個(gè)連續(xù)范圍的值
static final int SINGLE_SELECTION	一次選擇一個(gè)值

import javax.swing.*;
import java.awt.*;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.util.Vector;

class MyList{
    private JFrame frame = new JFrame("一");
    private Container cont = frame.getContentPane();
    private JList list1 = null;
    private JList list2 = null;
    public MyList(){
        this.frame.setLayout(new GridLayout(1,3));
        String n[] = {"A","B","C","D","E","F"};
        Vector<String> v = new Vector<String>();
        v.add("A");
        v.add("B");
        v.add("C");
        this.list1 = new JList(n);
        this.list2 = new JList(v);
        list1.setBorder(BorderFactory.createTitledBorder("請(qǐng)選擇"));
        list2.setBorder(BorderFactory.createTitledBorder("請(qǐng)選擇"));
        list1.setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);
        list2.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
        cont.add(this.list1);
        cont.add(this.list2);
        this.frame.setSize(300,200);
        this.frame.setVisible(true);
        this.frame.addWindowListener(new WindowAdapter() {
            @Override
            public void windowClosing(WindowEvent e) {
                super.windowClosing(e);
                System.exit(1);
            }
        });
    }
}
public class Hello {
    public static void main(String[] args) {
        new MyList();
    }
}

第一個(gè)JList通過(guò)字符串?dāng)?shù)組設(shè)置列表的內(nèi)容，并通過(guò)setSelectionMode()方法設(shè)置一次性可以選擇多個(gè)選項(xiàng)

第二個(gè)JList通過(guò)Vector設(shè)置列表的內(nèi)容，并通過(guò)setSelectionMode()方法將其設(shè)置成每次只能選擇一個(gè)選項(xiàng)

使用ListModel構(gòu)造JList

ListModel是一個(gè)專門用于創(chuàng)建JList列表內(nèi)容操作的接口

方法	作用
void addListDataListener(ListDataListener l)	加入數(shù)據(jù)改變事件的監(jiān)聽(tīng)
void removeListDataListener(ListDataListener l)	加入數(shù)據(jù)刪除時(shí)的監(jiān)聽(tīng)
Object getElementAt(int index)	返回指定索引處的內(nèi)容
int getSize()	返回列表長(zhǎng)度

import javax.swing.*;
import java.awt.*;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

class MyListModel extends AbstractListModel{
    private String n[]={"A","B","C","D"};

    @Override
    public int getSize() {
        return this.n.length;
    }

    public Object getElementAt(int ind){
        if(ind<this.n.length){
            return this.n[ind];
        }else {
            return null;
        }
    }
}
class MyList{
    private JFrame frame = new JFrame("一");
    private Container cont = frame.getContentPane();
    private JList list1 =null;
    public MyList(){
        this.list1 = new JList(new MyListModel());
        list1.setBorder(BorderFactory.createTitledBorder("請(qǐng)選擇"));
        list1.setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);
        cont.add(this.list1);
        this.frame.setSize(300,200);
        this.frame.setVisible(true);
        this.frame.addWindowListener(new WindowAdapter() {
            @Override
            public void windowClosing(WindowEvent e) {
                super.windowClosing(e);
                System.exit(1);
            }
        });
    }
}
public class Hello {
    public static void main(String[] args) {
        new MyList();
    }
}

JList事件處理

使用ListSelectionListener的監(jiān)聽(tīng)接口實(shí)現(xiàn)對(duì)JList中所選項(xiàng)的監(jiān)聽(tīng)

ListSelectionListener接口定義的方法

方法	作用
void valueChanged(ListSelectionEvent e)	當(dāng)值發(fā)生改變時(shí)調(diào)用

ListSelectionEvent的常用方法

方法	作用
public int getFirsIndex()	返回選擇的第1個(gè)選項(xiàng)的索引值
public int getLastIndex()	返回選擇的最后1個(gè)選項(xiàng)的索引值

對(duì)JList進(jìn)行監(jiān)聽(tīng)

import javax.swing.*;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;
import java.awt.*;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

class MyListModel extends AbstractListModel{
    private String n[]={"A","B","C","D"};

    @Override
    public int getSize() {
        return this.n.length;
    }

    public Object getElementAt(int ind){
        if(ind<this.n.length){
            return this.n[ind];
        }else {
            return null;
        }
    }
}
class MyList implements ListSelectionListener {
    private JFrame frame = new JFrame("一");
    private Container cont = frame.getContentPane();
    private JList list1 =null;
    public MyList(){
        this.list1 = new JList(new MyListModel());
        list1.setBorder(BorderFactory.createTitledBorder("請(qǐng)選擇"));
        list1.setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);
        list1.addListSelectionListener(this);
        cont.add(this.list1);
        this.frame.setSize(300,200);
        this.frame.setVisible(true);
        this.frame.addWindowListener(new WindowAdapter() {
            @Override
            public void windowClosing(WindowEvent e) {
                super.windowClosing(e);
                System.exit(1);
            }
        });
    }

    @Override
    public void valueChanged(ListSelectionEvent e) {
        int temp[] = list1.getSelectedIndices();
        System.out.print("選的的內(nèi)容是：");
        for(int i:temp){
            System.out.print(list1.getModel().getElementAt(i)+",");
        }
        System.out.println();
    }
}
public class Hello {
    public static void main(String[] args) {
        new MyList();
    }
}