【Java】javax.swing.JComboBox 组合框练习
1 import java.awt.event.ActionEvent; 2 import java.awt.event.ActionListener; 3 import java.awt.event.ItemEvent; 4 import java.awt.event.ItemListener; 5 import javax.swing.JComboBox; 6 import javax.swing.JTextField; 7 import javax.swing.JFrame; 8 import java.awt.BorderLayout; 9 10 class ExMyFrame65 extends JFrame implements ItemListener, ActionListener { 11 JComboBox comboBox ; 12 JTextField tf ; 13 String[] course = {"语文","数学","物理","英语"}; 14 15 ExMyFrame65(){ 16 super.setSize(400,300); 17 super.setTitle("JComBox组合框练习"); 18 super.setLayout(new BorderLayout()); 19 comboBox = new JComboBox(course); 20 tf = new JTextField("请选择课程"); 21 add(comboBox, BorderLayout.NORTH); 22 add(tf, BorderLayout.CENTER); 23 24 comboBox.setEditable(true); //允许组合框编辑输入 25 26 comboBox.addItemListener(this); //单选的时候是addItemListener() 27 comboBox.addActionListener(this); //输入选项的时候addActionListener() 28 29 } 30 31 @Override 32 public void actionPerformed(ActionEvent arg0) { 33 // TODO Auto-generated method stub 34 if (arg0.getSource() == comboBox) 35 tf.setText("选择了" + course[comboBox.getSelectedIndex()]); 36 } 37 38 @Override 39 public void itemStateChanged(ItemEvent arg0) { 40 // TODO Auto-generated method stub 41 if (arg0.getSource() == comboBox) 42 tf.setText("选择了" + course[comboBox.getSelectedIndex()]); 43 } 44 45 }