java下拉框代码,java中的下拉选择框

Java下拉框的整体代码？

import java.awt.*;

import javax.swing.*;

public class DemoJframe extends JFrame {

private JPanel p1 = new JPanel(new BorderLayout());

private JComboBoxString jcb = new JComboBoxString();

public DemoJframe() {

jcb.insertItemAt("no.1", 0);

jcb.insertItemAt("no.2", 1);

jcb.insertItemAt("no.3", 2);

p1.add(jcb, BorderLayout.NORTH);

this.add(p1);

}

public static void main(String[] args) {

JFrame frame = new DemoJframe();

frame.setTitle("MyFrame");

frame.setSize(300, 300);

frame.setLocationRelativeTo(null);

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

frame.setVisible(true);

}

}

相关问答

Q1: 如何利用Java Swing绘制下拉框JComboBox

利用Java Swing绘制下拉框JComboBox

第一步，双击打开MyEclipse开发软件，新建Java类SelectFrame，继承JFrame

第二步，声明一个JPanel和JComboBox，

private JComboBox selectBox = new JComboBox();

private JPanel panel = new JPanel();

第三步，给JComboBox和JPanel设置样式属性

panel.setBounds(150, 150, 400, 300);

panel.setToolTipText("下拉框");

panel.setLayout(new FlowLayout(FlowLayout.LEFT, 6, 6));

panel.setBackground(Color.LIGHT_GRAY);

panel.setVisible(true);

第四步，给JComboBox添加项目

selectBox.addItem("星期一");

selectBox.addItem("星期二");

selectBox.addItem("星期三");

selectBox.addItem("星期四");

selectBox.addItem("星期五");

selectBox.addItem("星期六");

selectBox.addItem("星期日");

selectBox.setVisible(true);

第五步，并将JLabel和JComboBox放入到JPanel上，在main方法内调用构造函数，

panel.add(label);

panel.add(selectBox);

第六步，设置JLabel样式属性

label.setText("星期");

label.setBounds(50, 50, 100, 30);

label.setFont(new Font("微软雅黑", Font.BOLD, 20));

label.setBackground(Color.BLUE);

label.setVisible(true);

Q2: Java源代码:POI操作Excel如何创建下拉框

Java代码package poiexcel; import java.io.FileOutputStream; import java.util.Date; import org.apache.poi.hssf.usermodel.DVConstraint; import org.apache.poi.hssf.usermodel.HSSFCell; import org.apache.poi.hssf.usermodel.HSSFDataValidation; import org.apache.poi.hssf.usermodel.HSSFRow; import org.apache.poi.hssf.usermodel.HSSFSheet; import org.apache.poi.hssf.usermodel.HSSFWorkbook; import org.apache.poi.hssf.util.CellRangeAddressList; public class POI { public static void main(String [] args) { String [] list={"东软","华信","SAP","海辉"}; new POI().createListBox(list); return; } public void createListBox (String [] list) { //文件初始化 HSSFWorkbook wb = new HSSFWorkbook(); HSSFSheet sheet = wb.createSheet("new sheet"); //在第一行第一个单元格，插入下拉框 HSSFRow row = sheet.createRow(0); HSSFCell cell = row.createCell(0); //普通写入操作 cell.setCellValue("请选择");//这是实验 //生成下拉列表 //只对（0，0）单元格有效 CellRangeAddressList regions = new CellRangeAddressList(0,0,0,0); //生成下拉框内容 DVConstraint constraint = DVConstraint.createExplicitListConstraint(list); //绑定下拉框和作用区域 HSSFDataValidation data_validation = new HSSFDataValidation(regions,constraint); //对sheet页生效 sheet.addValidationData(data_validation); //写入文件 FileOutputStream fileOut; try { fileOut = new FileOutputStream("workbook.xls"); wb.write(fileOut); fileOut.close(); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } //结束 System.out.println("Over"); } }责任编辑：linshi1

Q3: 如何用java实现下拉菜单

//核心代码

String[] sg= {"苹果","香蕉","樱桃","山楂"};

JComboBoxString jcb = new JComboBoxString(sg);

完整代码

import java.awt.*;

import javax.swing.*;

public class MFrame extends JFrame{

public MFrame() {

String[] sg= {"苹果","香蕉","樱桃","山楂"};

JComboBoxString jcb = new JComboBoxString(sg);

add(jcb);

setLayout(new FlowLayout());//把JFrame设置成流式布局

setTitle("测试");//设置窗口标题

setSize(220, 100);//设置窗口大小

setLocationRelativeTo(null);//设置窗口居中

setDefaultCloseOperation(EXIT_ON_CLOSE);//设置点击关闭退出jvm虚拟机

setVisible(true);//设置窗口可见

}

public static void main(String[] args) {

new MFrame();//创建窗口

}

}

Q4: java程序下拉列表设计

效果图

参考代码

import java.awt.event.*;

import java.util.Vector;

import javax.swing.*;

public class Demo extends JFrame implements ActionListener {

JButton btn;

VectorString vector=new VectorString();

JComboBoxString jcb;

public Demo() {

vector.add("公斤");

vector.add("每个");

vector.add("每盒");

JLabel jl = new JLabel("单位");

jcb = new JComboBoxString(vector);//可以传入一个数组或者一个Vector链表,对下拉框进行初始化

btn=new JButton("获取下拉框的文字");

btn.addActionListener(this);

JPanel jp = new JPanel();

jp.add(jl);

jp.add(jcb);

jp.add(btn);

add(jp);

setSize(300, 200);

setLocationRelativeTo(null);

setTitle("下拉框Demo");

setDefaultCloseOperation(EXIT_ON_CLOSE);

}

public static void main(String[] args) {

new Demo().setVisible(true);

}

@Override

public void actionPerformed(ActionEvent e) {

JOptionPane.showMessageDialog(this, (String)jcb.getSelectedItem());

}

}