touchend event doesn't work on Android

javascript android events touch

59,260

Solution 1

For anyone trying to figure out why touchend events are missing on Android v3 and v4 (maybe also v2.3), there is a long outstanding bug which only just got fixed in v4.1 (apparently):

http://code.google.com/p/android/issues/detail?id=4549

http://code.google.com/p/android/issues/detail?id=19827

To workaround this bug you have to call preventDefault() on either the touchstart or first touchmove event. Of course, this prevents the native scrolling, so you will need to re-implement that yourself.

Solution 2

This is how you need to use it properly. You capture the starting x,y when the finger goes to the screen. As the finger moves across, the touchmove event updates an ending x,y. When finished, the touchend fires -- but yes, it doesn't have a touches array, and thus a javascript error. This is why we only use it for capturing that this is an ending task (fingers left the screen) and then react to it. (In this case, I send an informative alert.)

var gnStartX = 0;
var gnStartY = 0;
var gnEndX = 0;
var gnEndY = 0;

window.addEventListener('touchstart',function(event) {
  gnStartX = event.touches[0].pageX;
  gnStartY = event.touches[0].pageY;
},false);

window.addEventListener('touchmove',function(event) {
  gnEndX = event.touches[0].pageX;
  gnEndY = event.touches[0].pageY;
},false);

window.addEventListener('touchend',function(event) {
  alert('START (' + gnStartX + ', ' + gnStartY + ')   END (' + gnEndX + ', ' + gnEndY + ')');
},false);

Solution 3

It's web development, so I am building a webpage that can utilize the touch events.

I figured out what the problem was.

When the touchend event is fired the event.touches[] array is empty, so a Javascript error is thrown. The event was being fired, but it didn't print anything out, because I was attempting to access undefined data. The emulator browser doesn't seem to have any Javascript debugging tools that I have found, and didn't even tell me when a Javascript error occurred, so it took me a while to figure it out.

Solution 4

I had the same problem and additionally binding the 'touchcancel' event solved it. Did some testing and when 'touchend' wasn't fired, then the 'touchcancel' event fired instead.

var onTouchEnd = function(){
  console.log("touch end");
}
document.addEventListener("touchend", onTouchEnd);
document.addEventListener("touchcancel", onTouchEnd);

Solution 5

map.addEventListener ('touchend', function (event) {
    var touch = event.changeTouches[0];
    ...
}

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59,260

Author by

Protos

Updated on August 02, 2022

Comments

Protos over 1 year

I've just started looking at doing some basic mobile web development on the android and an writing a test script to investigate the touch events. I've run the following code in the android emulator, and the touchend event never gets fired. Can anyone tell me why ?

I've tried in three versions of the emulator (1.6, 2.1 and 2.2) and all three behave in the same way.

Thanks in advance for any help you can give me.

Cheers, Colm

EDIT - I've also tried this using the XUI framework and have the same problem so I'm guessing I have a fundamental misunderstanding of how this stuff works ......

Map Test

    <meta name="description" content="" />
    <meta name="keywords" content="" />
    <meta name="language" content="english" />

    <meta name="viewport" content="minimum-scale=1.0,
                                   width=device-width,
                                   height=device-height,
                                   user-scalable=no">
    <script type="text/javascript">
        window.onload = function(){
            document.body.appendChild(
                    document.createTextNode("w: " + screen.width + " x " + "h : " +screen.height)
            );
           attachTouchEvents();
        }
        function attachTouchEvents() {
            console = document.getElementById("console");
            var map = document.getElementById("map");
            map.addEventListener ('touchstart', function (event) {
                event.preventDefault();
                var touch = event.touches[0];
                document.getElementById("touchCoord").innerHTML = "S : " + touch.pageX + " " + touch.pageY;
                document.getElementById("touchEvent").innerHTML = "Touch Start";
            }, false);

            map.addEventListener ('touchmove', function (event) {
                event.preventDefault();
                var touch = event.touches[0];
                document.getElementById("touchCoord").innerHTML = "M : " + touch.pageX + " " + touch.pageY;
                document.getElementById("touchEvent").innerHTML = "Touch Move";
            }, false);

            map.addEventListener ('touchend', function (event) {
                var touch = event.touches[0];
                document.getElementById("touchCoord").innerHTML = "E : " + touch.pageX + " " + touch.pageY;
                document.getElementById("touchEvent").innerHTML = "Touch End";
                event.preventDefault();
            }, false);
            console.innerHTML = "event attached";
        }
    </script>
    <style type="text/css">
        html, body {
            height:100%;
            width:100%;
            margin: 0;
            background-color:red;
        }
        #map {
            height: 300px;
            width: 300px;
            background-color:yellow;
        }
    </style>
</head>

<body>
    <div id="map"></div>
    <div id="touchCoord">Touch Coords</div>
    <div id="touchEvent">Touch Evnt</div>
    <div id="console">Console</div>

</body>