Question

急，java考试题》

编写应用程序实现：窗口取默认布局——BorderLayout布局，北面添加JComboBox组建，该组件有六个选项，分别表示六种商品名称。在中心添加一个文本区，当选择JComboBox组建中的某个选项后文本区显示该商品的价格和产地等信息

Answer 1

import java.awt.BorderLayout;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import javax.swing.DefaultComboBoxModel;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JTextArea;
import javax.swing.plaf.basic.BasicListUI;

/**
* @author sunsnowad
*
*/
public class Main {

public static void main(String[] args) {
final Object[] items = {"product1", "product2", "product3", "product4", "product5"};
final Object[] results = {"1价格产地", "2价格产地", "3价格产地", "4价格产地", "5价格产地"};
JFrame f = new JFrame();
f.setSize(400,300);

final JTextArea jt = new JTextArea();
f.add(jt, BorderLayout.CENTER);

JComboBox jb = new JComboBox();
f.add(jb, BorderLayout.NORTH);
DefaultComboBoxModel model = new DefaultComboBoxModel(items);
jb.setModel(model);
jb.addItemListener(new ItemListener() {

public void itemStateChanged(ItemEvent e) {
for(int i = 0; i < 5; i ++){
if(!e.getItem().toString().isEmpty() && e.getItem().toString().equals(items[i].toString())){
jt.setText(results[i].toString());
return;
}
}
}
});

f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setVisible(true);

}

}