JComboBox联动问题

Question

怎么这么快就沉了呢，大家帮忙看看吧，谢谢了！

Answer 1

你可以运行这段代码啊！package swingtest;import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class ProvinceCity extends JFrame implements ItemListener{ public static final String[] provinces={"湖南","广东"};
public static final String[] g_city={"广州","深圳"};
public static final String[] h_city={"长沙","湘潭"};

private JComboBox provinceBox;
private JComboBox cityBox;
private JLabel lable;
private String text="当前选择的省份是";

public ProvinceCity(){
init();
}

private void init(){


lable=new JLabel(text+"湖南");
provinceBox=new JComboBox(provinces);
provinceBox.setBorder(BorderFactory.createTitledBorder("请选择省份"));
provinceBox.addItemListener(this);
cityBox=new JComboBox(h_city);
cityBox.setBorder(BorderFactory.createTitledBorder("请选择城市"));

this.setLayout(new GridLayout(1,3));
this.add(provinceBox);
this.add(cityBox);
this.setTitle("省和城市联动演示");
this.setLocation(200, 200);
this.setSize(350, 100);
this.setResizable(false);
this.setVisible(true); this.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
} public void itemStateChanged(ItemEvent event) {
if(event.getStateChange()==ItemEvent.SELECTED){
String temp=(String)provinceBox.getSelectedItem();
if(temp!=null&&temp.equals("广东")){
cityBox.setModel(new DefaultComboBoxModel(g_city));
lable.setText(text+"广东");
}else{
cityBox.setModel(new DefaultComboBoxModel(h_city));
lable.setText(text+"湖南");
}
}
}

public static void main(String[] args) {
new ProvinceCity();
}
}