我java代码中的下拉列表设好后为什么无法下拉?

来源:百度知道 编辑:UC知道 时间:2024/05/19 18:17:58
package FAA;

import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.FlowLayout;
import java.awt.GridLayout;
import java.awt.Panel;
import java.awt.Toolkit;

import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JTextField;
import javax.swing.text.JTextComponent;
import javax.swing.text.AbstractDocument.Content;

public class FAIM extends JFrame {
JLabel lblLocation = new JLabel("坐落位置");
JLabel lblBuildTime = new JLabel("建成年代");
JLabel lblUsage = new JLabel("房屋用途");
JLabel lblNumber = new JLabel("房屋套数");
JLabel lblType = new JLabel("房屋类型");
JLabel lblArea = new JLabel("建筑面积");
JLabel lblUsageArea = new JLabel("使用面积");

JTextField txtLocation = new JTextField(30);
JTextField txtBuil

pCenter, pNorth, pSouth不要用Panel,用JPanel。Awt和Swing的控件在层次结构上不要混用(在其他情况下也建议不要混用)。

==== 修改后的代码 ====
package FAA;

import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.FlowLayout;
import java.awt.GridLayout;
import java.awt.Panel;
import java.awt.Toolkit;

import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;

public class FAIM extends JFrame {
    JLabel lblLocation = new JLabel("坐落位置");
    JLabel lblBuildTime = new JLabel("建成年代");
    JLabel lblUsage = new JLabel("房屋用途");
    JLabel lblNumber = new JLabel("房屋套数");
    JLabel lblType = new JLabel("房屋类型");
    JL