On Nov 18, 12:20 am, radin <radinj...@gmail.com> wrote:
> On Nov 17, 3:27 am, naugem <nau...@gmail.com> wrote:
>
>
>
> > Hello,
>
> > I have a simple web app that consists of a circle moving around. When
> > I do a swipe, the app freezes and the circle stops moving, and I have
> > to do another swipe/tap to set it in motion again. This only happens
> > in Andoid 2.2 devices (2.3 works OK). Does anyone know why this
> > happens? How can I avoid this?
>
> > Here's the code:
>
> > <!doctype html>
> > <html>
> > <head>
> > <meta charset="UTF-8" />
> > <title>Canvas Test</title>
> > <script type="text/javascript" src="touch.js"></script>
> > </head>
> > <body>
> > <section>
> > <div>
> > <canvas id="canvas" width="400" height="300">
> > This text is displayed if your browser
> > does not support HTML5 Canvas.
> > </canvas>
> > <canvas id="canvas2" width="400" height="300">
> > This text is displayed if your browser
> > does not support HTML5 Canvas.
> > </canvas>
> > </div>
>
> > <script type="text/javascript">
> > var canvas;
> > var ctx;
> > var x = 400;
> > var y = 300;
> > var dx = 2;
> > var dy = 4;
> > var WIDTH = 400;
> > var HEIGHT = 300;
>
> > function circle(x,y,r) {
> > ctx.beginPath();
> > ctx.arc(x, y, r, 0, Math.PI*2, true);
> > ctx.fill();
> > }
>
> > function rect(x,y,w,h) {
> > ctx.beginPath();
> > ctx.rect(x,y,w,h);
> > ctx.closePath();
> > ctx.fill();
> > }
>
> > function clear() {
> > ctx.clearRect(0, 0, WIDTH, HEIGHT);
> > }
>
> > function init() {
>
> >
> > document.getElementById('canvas').addEventListener('touchstart',
> > touchStart);
> >
> > document.getElementById('canvas').addEventListener('touchmove',
> > touchMove);
> >
> > document.getElementById('canvas').addEventListener('touchend',
> > touchEnd);
>
> > canvas = document.getElementById("canvas");
> > ctx = canvas.getContext("2d");
> > return setInterval(draw, 10);
> > }
>
> > function draw() {
> > clear();
> > ctx.fillStyle = "#FAF7F8";
> > rect(0,0,WIDTH,HEIGHT);
> > ctx.fillStyle = "#444444";
> > circle(x, y, 10);
>
> > if (x + dx > WIDTH || x + dx < 0)
> > dx = -dx;
> > if (y + dy > HEIGHT || y + dy < 0)
> > dy = -dy;
>
> > x += dx;
> > y += dy;
> > }
>
> > init();
> > </script>
> > </section>
> > </body>
> > </html>
>
> > <<--- touch.js --->>
>
> > var triggerElementID = null;
> > var fingerCount = 0;
> > var startXPosition = 0;
> > var startYPosition = 0;
> > var currentXPosition = 0;
> > var currentYPosition = 0;
> > var minLength = 72;
> > var swipeLength = 0;
> > var swipeDirection = null;
>
> > function touchStart(event,passedName) {
> > event.preventDefault();
> > fingerCount = event.touches.length;
>
> > if (fingerCount == 1 ) {
> > startXPosition = event.touches[0].pageX;
> > startYPosition = event.touches[0].pageY;
> > triggerElementID = passedName ? passedName : this.id;
> > } else {
> > touchCancel(event);
> > }
>
> > }
>
> > function touchMove(event) {
> > event.preventDefault();
>
> > if (event.touches.length == 1 ) {
> > currentXPosition = event.touches[0].pageX;
> > currentYPosition = event.touches[0].pageY;
> > } else {
> > touchCancel(event);
> > }
>
> > }
>
> > function touchEnd(event) {
> > try {
> > event.preventDefault();
> > if ( fingerCount == 1 && currentXPosition != 0 ) {
> > currentXPosition = event.touches[0].pageX;
> > currentYPosition = event.touches[0].pageY;
>
> > swipeLength =
> > Math.round(Math.sqrt(Math.pow(currentXPosition -
> > startXPosition,2) + Math.pow(currentYPosition - startYPosition,2)));
>
> > if ( swipeLength >= minLength ) {
> > caluculateAngle();
> > }
> > }
> > } finally {
> > touchCancel(event);
> > }
>
> > }
>
> > function touchCancel(event) {
> > fingerCount = 0;
> > startXPosition = 0;
> > startYPosition = 0;
> > currentXPosition = 0;
> > currentYPosition = 0;
> > swipeLength = 0;
> > swipeDirection = null;
> > triggerElementID = null;
>
> > }
>
> > Thanks!
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