Java程序设计 图形用户界面 【十一】列表框JList
列表框JList
JList常用方法
| 方法 | 作用 |
|---|---|
| public JList(ListModel dataModel) | 根据ListModel构造JList |
| public JList(Object[] listData) | 根据对象数组构造JList |
| public JList(Vector<?> listData) | 根据一个Vector构造JList |
| public void setSelectionMode(int selectionMode) | 设置选择模式，是多选还是单选 |
| public ListModel getModel() | 返回列表框的列表模型 |
| public int[] getSelectedIndices() | 返回所选择的全部数组 |
可以通过ListSelectionModel接口完成列表框是多选还是单选
ListSelectionModel定义的常量
| 常量 | 作用 |
|---|---|
| static final int MULTIPLE_INTERVAL_SELECTION | 一次选择一个或多个连续的索引范围 |
| static final int SINGLE_INTERVAL_SELECTION | 一次选择一个连续范围的值 |
| static final int SINGLE_SELECTION | 一次选择一个值 |
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("请选择"));
list2.setBorder(BorderFactory.createTitledBorder("请选择"));
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();
}
}
第一个JList通过字符串数组设置列表的内容，并通过setSelectionMode()方法设置一次性可以选择多个选项
第二个JList通过Vector设置列表的内容，并通过setSelectionMode()方法将其设置成每次只能选择一个选项
使用ListModel构造JList
ListModel是一个专门用于创建JList列表内容操作的接口
| 方法 | 作用 |
|---|---|
| void addListDataListener(ListDataListener l) | 加入数据改变事件的监听 |
| void removeListDataListener(ListDataListener l) | 加入数据删除时的监听 |
| Object getElementAt(int index) | 返回指定索引处的内容 |
| int getSize() | 返回列表长度 |
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("请选择"));
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事件处理
使用ListSelectionListener的监听接口实现对JList中所选项的监听
ListSelectionListener接口定义的方法
| 方法 | 作用 |
|---|---|
| void valueChanged(ListSelectionEvent e) | 当值发生改变时调用 |
ListSelectionEvent的常用方法
| 方法 | 作用 |
|---|---|
| public int getFirsIndex() | 返回选择的第1个选项的索引值 |
| public int getLastIndex() | 返回选择的最后1个选项的索引值 |
对JList进行监听
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("请选择"));
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("选的的内容是：");
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();
}
}
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