PhoneGap开发的指南针示例

admin · 发表于 2013-7-15 18:18:00

phonegap开发的指南针示例如下,代码分享给大家

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>指南针</title>
<meta http-equiv="Content-Type" content="text/html; charset=GBK" />
<link href="css/css.css" rel="stylesheet" type="text/css" />
<script type="text/javascript" charset="utf-8" src="phonegap.js"></script>
<script type="text/javascript" charset="utf-8">
var b=10,c=100,d=20,t=0,ang=0;drgNum=0;
var cv, ctx,prevAng = 0,currAng = 0;
var img = new Image();
img.src = "images/znz_04.png";
// watchID是当前 “watchHeading” 的引用
var watchID = null;
document.addEventListener("backbutton", onBackKeyDown, false);
// 等待加载PhoneGap
document.addEventListener("deviceready", onDeviceReady, false);
//
function onDeviceReady() {
//startWatch();
// Register the event listener
document.addEventListener("backbutton", onBackKeyDown, false);
}
// 开始监视罗盘
function startWatch() {
// 每隔3秒钟更新一次罗盘数据
var options = { frequency: 10 };
watchID = navigator.compass.watchHeading(onSuccess, onError, options);
}
// 停止监视罗盘
function stopWatch() {
if (watchID) {
navigator.compass.clearWatch(watchID);
watchID = null;
}
var element = document.getElementById('heading');
element.innerHTML = '停止' + drgNum+'°';
}
// onSuccess: 返回罗盘的当前朝向
function onSuccess(heading) {
var fangweiStr = "";
var element = document.getElementById('heading');
element.innerHTML = getPositonStr(360-heading)+'' + Math.round(heading)+'°';
setRotationFun((360-heading)*Math.PI/180);
drgNum = heading;
}
// onError: 获取罗盘朝向失败
function onError() {
alert('onError!获取罗盘朝向失败');
stopWatch();
}
function getPositonStr(d){
var str = "北";
if(d>=340 && d<20 ){
str="北";
}
if(d<=340 && d>290){
str="东北";
}
if(d<=290 && d>250){
str="东";
}
if(d<=250 && d>200){
str="东南";
}
if(d<=250 && d>200){
str="东南";
}
if(d<=200 && d>160){
str="南";
}
if(d<=160 && d>110){
str="西南";
}
if(d<=110 && d>70){
str="西";
}
if(d<=70 && d>20){
str="西北";
}
return str;
}
function setRotationFun(ang){
//setRotationFun(ang*Math.PI/180);
cv = document.getElementById("compassImgDiv");
ctx = cv.getContext("2d");
cv.width = 355;
cv.height = 355;
ctx.save();
ctx.translate(cv.width/2, cv.height/2);
ctx.scale(1, 1);
ctx.rotate(ang);
ctx.drawImage(img, -355/2, -355/2);
ctx.restore();
}
//格式化数字，保留num位小数
function formatNum(str,num){
var s = parseFloat(str);
if(!num) num=4;
if(isNaN(s)){
return;
}
s = s.toFixed(num);
if(s=="" || s<0) s=0;
return s;
}
// Handle the back button
//
function onBackKeyDown() {
// 显示确认对话框
navigator.notification.confirm(
'是否要退出罗盘程序', // 显示信息
onConfirm, // 按下按钮后触发的回调函数，返回按下按钮的索引
'退出程序', // 标题
'确认,取消' // 按钮标签
);
}
// 处理确认对话框返回的结果
function onConfirm(button) {
if(button == 1){
navigator.app.exitApp();
}
}
</script>
</head>
<body>
<div class="all">
<div id="heading" class="top">点击开始</div>
<div class="middle">
<canvas id="compassImgDiv" class="dial"></canvas>
</div>
<div class="bottom">
<div class="start"><img src="images/tm.gif" width="198px" height="79" border="0" onclick="startWatch();"></div>
<div class="kong"></div>
<div class="stop"><img src="images/tm.gif" width="198px" height="79" border="0" onclick="stopWatch();"></div>
</div>
</div>
</body>
</html>

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