PhoneGap实现重力感应

<!DOCTYPE html>

<html>

<head>

<meta charset="utf-8">

<title>phonegap_device_network_notification01</title>

<link href="../jquery.mobile-1.3.2.css" rel="stylesheet" type="text/css"/>

<script src="../jquery.js" type="text/javascript"></script>

<script src="../jquery.mobile-1.3.2.js" type="text/javascript"></script>

<script src="../cordova.js" type="text/javascript"></script>

<style type="text/css">

    #ball {

    position: absolute;

    z-index: 0;

    left: 20px;

    top: 100px;

    background: #f00;

}

</style>

<script type="text/javascript" charset="utf-8">

    var watchID = null;

    document.addEventListener("deviceready", onDeviceReady, false);

    function drawCircle(x,y) {

        var ctx = document.getElementById("ball").getContext('2d');

        var rd = 10;

        ctx.beginPath();

        ctx.arc(x, y, rd, 0, Math.PI * 2, false);

        ctx.closePath();

        ctx.fillStyle = "yellow";

        ctx.fill();

    }

    function clear() {

        var ctx = document.getElementById("ball").getContext('2d');

        ctx.clearRect(0,0,200,200);

    }

    function onDeviceReady() {

        drawCircle(10,10);

        startWatch();

    }

    function startWatch() {

        var options = { frequency: 40 };

        watchID = navigator.accelerometer.watchAcceleration(onSuccess, onError, options);

    }

    function stopWatch() {

        if (watchID) {

            navigator.accelerometer.clearWatch(watchID);

            watchID = null;

        }

    }

    var oldX = 10, oldY = 10;

    // 获取加速度信息成功后的回调函数

    function onSuccess(newValue) {

        if(10<=oldX<180&&10<=oldY<180){

            clear();

            drawCircle(oldX,oldY);

        }

        oldX -= newValue.x;

        oldY += newValue.y;

        var element = document.getElementById('accelerometer');

        element.innerHTML = 'X: ' + oldX + '<br />' +

                            'Y: ' + oldY + '<br />';

    }

    // 获取加速度信息失败后的回调函数

    function onError() {

        alert('onError!');

    }

</script>

</head>

<body>

<div data-role="page">

        <div data-role="header">

            <h1>PhoneGap100实战</h1>

        </div>

        <div data-role="content">

            <div id="accelerometer">开启重力感应...</div>

            <button onclick="stopWatch();">停止重力感应</button>

            <canvas id="ball" width="200" height="200"></canvas>

        </div>

        <div data-role="footer">

            <h4>&nbsp;</h4>

        </div>

</div>

</body>

</html>
巴特西

PhoneGap实现重力感应

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