[转]applet导航菜单
import java.applet.*;
import java.awt.*;
import java.awt.event.*;
import java.util.StringTokenizer;
import java.net.*;
public class Navigator extends Applet implements ActionListener, ItemListener {
String[][] urlArray; //网址数组
String[] target; //打开网页的方式的变量
Button[] button; //按钮数组
List[] list; //列表框
Dimension largeButtonSize;
Component prevList; //列表框变量
Object prevSource; //按钮变量,标识导航条是否打开
int rows, smallButtonHeight, listHeightSize;
boolean startSwitch = true;
public void init() {
String bcString, fcString, fontName, fontSize, fontStyle;
Color buttonColor, fontColor;
int token = 0, fontSizeInt, fontStyleInt;
//根据rows定义各个数据的容量
rows = Integer.parseInt(getParameter("rows"));
urlArray = new String[rows][];
target = new String[rows];
button = new Button[rows];
list = new List[rows];
//根据参数设置字符的字体,大小与风格
fontName = getParameter("fontName");
if (fontName == null) fontName = "SansSerif";
fontStyle = getParameter("fontStyle");
if (fontStyle == null) fontStyleInt = 1;
else fontStyleInt = Integer.parseInt(fontStyle);
fontSize = getParameter("fontSize");
if (fontSize == null) fontSizeInt = 12;
else fontSizeInt = Integer.parseInt(fontSize);
//设置按钮颜色
bcString = getParameter("buttonColor");
if (bcString == null) buttonColor = new Color (0);
else buttonColor = new Color (Integer.parseInt(bcString));
//设置字体颜色
fcString = getParameter("fontColor");
if (fcString == null) fontColor = new Color (16777215);
else fontColor = new Color (Integer.parseInt(fcString));
//设置Applet的布局
this.setLayout(new GridLayout(rows, 1));
for (int i = 0; i < rows; i++) {
//读取Menu变量的数值
StringTokenizer reader = new StringTokenizer (getParameter(
"menu" + i),",");
urlArray[i] = new String[reader.countTokens()];
//创建按钮的代码
button[i] = new Button (reader.nextToken());
button[i].setFont(new Font (fontName, fontStyleInt, fontSizeInt));
button[i].setBackground(buttonColor);
button[i].setForeground(fontColor);
this.add(button[i]);
button[i].addActionListener(this);
//取得网页打开方式的数据
target[i] = reader.nextToken();
//创建列表框
list[i] = new List();
while (reader.hasMoreTokens()) {
list[i].add(reader.nextToken());
//i定义哪一个列表框,token表示网址在列表框的位置
urlArray[i][token++] = reader.nextToken();
}
list[i].addItemListener(this);
token = 0;
}
}
//该事件在init()事件之后发生和当浏览器重新获得焦点时发生
public void start() {
if (startSwitch) {
//取得按钮的最大长度
largeButtonSize = button[0].getSize();
//取得按钮的最小长度
smallButtonHeight = (int)(largeButtonSize.height / 2);
//根据最大,最小长度计算按钮的高度
listHeightSize = (largeButtonSize.height * rows) -
(smallButtonHeight * rows);
startSwitch = false;
} else {
//删除所有按钮
this.removeAll();
//向Applet重新加入按钮
for (int i = 0; i < rows; i++) {
this.add(button[i]);
}
prevSource = null;//将按钮变量定义为空值
}
}
//处理按钮的单击事件
public void actionPerformed(ActionEvent evt) {
int currentHeightSize = 0;
boolean oneElementList = false;
Object source = evt.getSource();
//将前一个列表框设为不可视
if (prevList != null)
prevList.setVisible(false);
//确定哪一个按钮被击中
for (int i = 0; i < rows; i++) {
//导航条有一个网址的执行代码
if (source == button[i] && list[i].getItemCount() == 1) {
//根据最大的长度与高度重新设置按钮的大小
if (!largeButtonSize.equals(button[0].getSize())) {
for (int j = 0; j < rows; j++) {
button[j].setBounds(0, currentHeightSize, largeButtonSize.
width, largeButtonSize.height);
currentHeightSize += largeButtonSize.height;
}
}
oneElementList = true;
try {
//打开网页
AppletContext context = getAppletContext();
URL u = new URL(urlArray[i][0]);
context.showDocument(u, target[i]);
}
catch(Exception e) {
showStatus("Error " + e);
}
break;
}
}
//导航条多于一个网址的执行代码
if (!oneElementList) {
//导航条处于打开状态的执行代码
if (prevSource == source) {
for (int i = 0; i < rows; i++) {
button[i].setBounds(0, currentHeightSize, largeButtonSize.width,
largeButtonSize.height);
currentHeightSize += largeButtonSize.height;
}
prevSource = null;
}
//导航条处于关闭状态的执行代码
else {
prevSource = source;
for (int i = 0; i < rows; i++) {
button[i].setBounds(0, currentHeightSize, largeButtonSize.
width, smallButtonHeight);
currentHeightSize += smallButtonHeight;
//显示相关的列表框
if (source == button[i]) {
prevList = list[i];
this.add(list[i]);
list[i].setBounds(0, currentHeightSize, largeButtonSize.
width, listHeightSize);
list[i].setVisible(true);
currentHeightSize += listHeightSize;
}
}
}
}
}
//列表框的选择事件
public void itemStateChanged(ItemEvent evt) {
List source = (List) evt.getSource();
int listIndex = source.getSelectedIndex();
//处理列表框的选择事件
if (evt.getStateChange() == ItemEvent.SELECTED) {
for (int i = 0; i < rows; i++) {
//应用下面语句找到选择项
if (source == list[i]) {
try {
//使用context类的showDocument方法打开联接
AppletContext context = getAppletContext();
URL u = new URL(urlArray[i][listIndex]);
context.showDocument(u, target[i]);
}
catch(Exception e) {
showStatus("Error " + e);
}
break;
}
}
}
}
}
==========================================================
网页为:
下面是引用该applet的网页文件：
<applet width="200" height="500" code="Navigator.class">
<param name="buttonColor" value="952768">
<param name="fontColor" value="16777215">
<!--导航1 main指打开新的窗口,其它联接都在该窗口打开-->
<param name="menu0" value="Java资源网址,main,
主页, http://java.sun.com,
JDK下载网址, http://java.sun.com/j2se/1.4/download.html,
J2EE下载网址, http://java.sun.com/j2ee/download.html">
<!--导航2 _parent指在当前窗口打开连接-->
<param name="menu1" value="Borland资源网址,_parent,
主页, http://www.borland.com,
Jbuilder下载网址, http://www.borland.com/products/downloads
/download_jbuilder.html,">
<!--导航3-->
<param name="menu2" value="Mysql资源网址,_parent,
Mysql官方网站,http://www.mysql.org,
Mysql数据库下载网址,http://www.mysql.com/downloads/index.html,
MyOdbc下载网址,http://www.mysql.com/products/myodbc/index.html
">
<!--导航4-->
<param name="menu3" value="XML资源网址,main,
XML官方网站,http://www.xml.org,
XML新闻网站,http://www.xml.org/xml/news_market.shtml">
<!--导航5-->
<param name="menu4" value="Oracle资源网址,main,
Oracle官方网址,http://www.oracle.com,
Oracle 9i数据库下载网址,
http://otn.oracle.com/software/content.html">
<!--定义导航条的总数-->
<param name="rows" value="5">
</applet>