通过Android中的Javascript访问加速度计？

Question

Is there any way to access accelerometer data using Javascript on Android's browser? I know it supports "onorientationchange", but I'd like to get everything.

Clarification: I'm asking how to do this in a website, not a native app.

Answer 1

As of ICS, Android 4.0, you can use the 'devicemotion' event via a JavaScript event listener to access the accelerometer data. See the W3C documentation on how to access it - http://dev.w3.org/geo/api/spec-source-orientation.html .

Note - The W3C documentation title is named with 'device orientation', but the spec does indeed include 'devicemotion' event documentation.

Answer 2

Making an update to this thread.

HTML5 lets someone do this. Detecting whether or not an accelerometer is present is easy.

    if (window.DeviceMotionEvent == undefined) {
        //No accelerometer is present. Use buttons. 
        alert("no accelerometer");
    }
    else {
        alert("accelerometer found");
        window.addEventListener("devicemotion", accelerometerUpdate, true);
    }

In the function that you define to receive the accelerometer events, you can look at the accelerationIncludingGravity member.

function accelerometerUpdate(e) {
   var aX = event.accelerationIncludingGravity.x*1;
   var aY = event.accelerationIncludingGravity.y*1;
   var aZ = event.accelerationIncludingGravity.z*1;
   //The following two lines are just to calculate a
   // tilt. Not really needed. 
   xPosition = Math.atan2(aY, aZ);
   yPosition = Math.atan2(aX, aZ);
}

More information can be found here: http://dev.w3.org/geo/api/spec-source-orientation.html

Answer 3

You could try with PhoneGap that provides API to access the accelerometer from javascript.

Here the documentation.

Answer 4

If you are trying to access the accelerometer from a webpage hosted on a server (verus one integrated into a native application through WebView ), than the accelerometer data does not appear to be available as of now for Android. You can find a more detailed assessment here: http://www.mobilexweb.com/blog/android-froyo-html5-accelerometer-flash-player .

You might also want to check out this SO post: Detect rotation of Android phone in the browser with JavaScript

Answer 5

If I'm reading the docs correctly, you could set up a class (within Java/Android) that provides the accelerometer functionality you need in public functions.

Then setup a javascript interface for the webview using the addJavascriptInterface call, which makes the public functions in that class available to be called from within javascript.

Answer 6

Looking at this post flash.sensors.Accelerometer on Android within web browser it seems accelerometer data is available to flash. So a possible workaround (at least for devices which have flash) would be a small flash applet which grabbed the data for you.

Sounds like a hack, but still sounds better than making the whole thing in flash