这个我的一个小程序,怎样才能实现在实现ItemListener事件中只执行SELECTED而不执行DESELECTED?
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import javax.swing.JComboBox;
import javax.swing.JFrame;public class JComboBoxDemo extends JFrame implements ItemListener { private JComboBox cob = null; public JComboBoxDemo() {
this.setTitle("westfish");
this.setSize(400, 300);
this.setLocationRelativeTo(null); cob = new JComboBox();
cob.setBounds(100, 100, 100, 26);
cob.addItem("请选择");
cob.addItem("管理员");//复选框添加元素
cob.addItem("教师");
cob.addItem("学生");
cob.addItemListener(this); this.getContentPane().add(cob);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setVisible(true);
} public void itemStateChanged(ItemEvent e) {
System.out.println("e.getStateChange=" + e.getStateChange());
if (e.getStateChange() == ItemEvent.SELECTED) {
System.out.println("choose");
}
if (e.getStateChange() == ItemEvent.DESELECTED) {
System.out.println("not choose");
}
} public static void main(String[] args) {
new JComboBoxDemo();
}
}
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import javax.swing.JComboBox;
import javax.swing.JFrame;public class JComboBoxDemo extends JFrame implements ItemListener { private JComboBox cob = null; public JComboBoxDemo() {
this.setTitle("westfish");
this.setSize(400, 300);
this.setLocationRelativeTo(null); cob = new JComboBox();
cob.setBounds(100, 100, 100, 26);
cob.addItem("请选择");
cob.addItem("管理员");//复选框添加元素
cob.addItem("教师");
cob.addItem("学生");
cob.addItemListener(this); this.getContentPane().add(cob);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setVisible(true);
} public void itemStateChanged(ItemEvent e) {
System.out.println("e.getStateChange=" + e.getStateChange());
if (e.getStateChange() == ItemEvent.SELECTED) {
System.out.println("choose");
}
if (e.getStateChange() == ItemEvent.DESELECTED) {
System.out.println("not choose");
}
} public static void main(String[] args) {
new JComboBoxDemo();
}
}
if (e.getStateChange() == ItemEvent.DESELECTED) {
System.out.println("not choose");
}//或者改成如下
if (e.getStateChange() == ItemEvent.DESELECTED) {
//什么也不做
}