//核心代碼
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String[]?sg=?{"蘋果","香蕉","櫻桃","山楂"};
JComboBoxString?jcb?=?new?JComboBoxString(sg);
完整代碼
import?java.awt.*;
import?javax.swing.*;
public?class?MFrame?extends?JFrame{
public?MFrame()?{
String[]?sg=?{"蘋果","香蕉","櫻桃","山楂"};
JComboBoxString?jcb?=?new?JComboBoxString(sg);
add(jcb);
setLayout(new?FlowLayout());//把JFrame設(shè)置成流式布局
setTitle("測試");//設(shè)置窗口標(biāo)題
setSize(220,?100);//設(shè)置窗口大小
setLocationRelativeTo(null);//設(shè)置窗口居中
setDefaultCloseOperation(EXIT_ON_CLOSE);//設(shè)置點(diǎn)擊關(guān)閉退出jvm虛擬機(jī)
setVisible(true);//設(shè)置窗口可見
}
public?static?void?main(String[]?args)?{
new?MFrame();//創(chuàng)建窗口
}
}
代碼如下:
import?java.awt.Color;
import?java.awt.Dimension;
import?java.awt.FlowLayout;
import?java.awt.event.ItemEvent;
import?javax.swing.*;
public?class?App?extends?JFrame?{
private?JComboBoxString?comboBox;
private?JListString?list;
public?App()?{
this.setSize(300,?200);
this.setDefaultCloseOperation(DISPOSE_ON_CLOSE);? //?設(shè)置關(guān)閉方式
this.setLayout(new?FlowLayout());
//?定義一些選項(xiàng)
String[]?options?=?{?"紅",?"黃",?"藍(lán)",?"綠"?};?
//?創(chuàng)建下拉列表
comboBox?=?new?JComboBox(options);?
//?添加選擇事件監(jiān)聽器,選擇時觸發(fā)
comboBox.addItemListener(e?-?{
if?(e.getStateChange()?==?ItemEvent.SELECTED)
setBackground((String)e.getItem());
});
this.add(comboBox);
//?創(chuàng)建列表框
list?=?new?JList(options);
list.setPreferredSize(new?Dimension(50,?50));
//?添加選擇事件監(jiān)聽器,選擇時觸發(fā)
list.addListSelectionListener(e?-?setBackground(options[list.getSelectedIndex()]));
this.add(new?JScrollPane(list));
}
//?設(shè)置窗口背景
private?void?setBackground(String?color)?{
switch(color)?{
case?"紅":
getContentPane().setBackground(Color.RED);
break;
case?"黃":
getContentPane().setBackground(Color.YELLOW);
break;
case?"藍(lán)":
getContentPane().setBackground(Color.BLUE);
break;
case?"綠":
getContentPane().setBackground(Color.GREEN);
break;
}
}
public?static?void?main(String[]?args)?{
new?App().setVisible(true);
}
}
運(yùn)行結(jié)果:
Java代碼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={"東軟","華信","SAP","海輝"}; 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"); //在第一行第一個單元格,插入下拉框 HSSFRow row = sheet.createRow(0); HSSFCell cell = row.createCell(0); //普通寫入操作 cell.setCellValue("請選擇");//這是實(shí)驗(yàn) //生成下拉列表 //只對(0,0)單元格有效 CellRangeAddressList regions = new CellRangeAddressList(0,0,0,0); //生成下拉框內(nèi)容 DVConstraint constraint = DVConstraint.createExplicitListConstraint(list); //綁定下拉框和作用區(qū)域 HSSFDataValidation data_validation = new HSSFDataValidation(regions,constraint); //對sheet頁生效 sheet.addValidationData(data_validation); //寫入文件 FileOutputStream fileOut; try { fileOut = new FileOutputStream("workbook.xls"); wb.write(fileOut); fileOut.close(); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } //結(jié)束 System.out.println("Over"); } }責(zé)任編輯:linshi1
第一個下拉框綁定一個onchange事件,第二個下拉框保持為沒有選項(xiàng),當(dāng)選中第一個下框某項(xiàng)時在動態(tài)獲取第二個下拉框的內(nèi)容
本文標(biāo)題:java下拉框代碼是什么 java下拉框選擇怎么設(shè)置的
本文來源:http://www.muchs.cn/article28/doeopcp.html
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