java的JList监听判断怎么写?

主要的就是监听要用ListSelectionListener，对整个jlist进行监听即可，事件源e.getSource要强转为JList，下面给出刚写的例子：

public class BaiDuKnows extends JFrame implements ListSelectionListener

{

//创建列表

private JList jl=new JList()

private JLabel label =new JLabel("香蕉苹果大鸭梨等待你的选择！")

//创建字符串数组

private String[] str={"香蕉","苹果","大鸭梨"}

//创建复选框数组

public BaiDuKnows()

{

//设置列表的数据模型

jl.setListData(str)

//为列表注册ListSelectionEvent监听器

jl.addListSelectionListener(this)

jl.setBounds(0, 0, 150, 200)

label.setBounds(180, 0, 200, 200)

this.add(jl)

this.add(label)

this.setLayout(null)

this.setBounds(100,100,360,250)

this.setVisible(true)

this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE)

}

//实现ListSelectionListener接口中的事件处理方法

public void valueChanged(ListSelectionEvent e)

{

Object obj=((JList)e.getSource()).getSelectedValue()

if(obj.equals("香蕉"))

{

label.setText("你选的是banana")

}

else if(obj.equals("苹果"))

{

label.setText("你选的是apple")

}

else if(obj.equals("大鸭梨"))

{

label.setText("你选的是pear")

}

else

{

label.setText("你选的是球！！")

}

}

public static void main(String[] args)

{

new BaiDuKnows()

}

}

因为鼠标按下的时候会触发事件，鼠标放开的时候又会触发一次事件。

你可以判断event.getValueIsAdjusting()，只有第一次鼠标按下的时候才会返回true

ListSelectionListener listSelectionListener = new ListSelectionListener() {

public void valueChanged(ListSelectionEvent listSelectionEvent) {

System.out.print("First index: " + listSelectionEvent.getFirstIndex())

System.out.print(", Last index: " + listSelectionEvent.getLastIndex())

boolean adjust = listSelectionEvent.getValueIsAdjusting()

System.out.println(", Adjusting? " + adjust)

if (!adjust) {

JList list = (JList) listSelectionEvent.getSource()

int selections[] = list.getSelectedIndices()

Object selectionValues[] = list.getSelectedValues()

for (int i = 0, n = selections.lengthi <ni++) {

if (i == 0) {

System.out.print(" Selections: ")

}

System.out.print(selections[i] + "/" + selectionValues[i] + " ")

}

System.out.println()

}

}

}

kcLst.addListSelectionListener(listSelectionListener)

---