license: Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements. See the NOTICE file distributed with this work for additional information regarding copyright ownership. The ASF licenses this file to you under the Apache License, Version 2.0 (the “License”); you may not use this file except in compliance with the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
At a regular interval, get the acceleration along the x, y, and z axis.
var watchID = navigator.accelerometer.watchAcceleration(accelerometerSuccess, accelerometerError, [accelerometerOptions]);
The accelerometer is a motion sensor that detects the change (delta) in movement relative to the current position. The accelerometer can detect 3D movement along the x, y, and z axis.
The accelerometer.watchAcceleration
method retrieves the device‘s current Acceleration
at a regular interval, executing the accelerometerSuccess
callback function each time. Specify the interval in milliseconds via the acceleratorOptions
object’s frequency
parameter.
The returned watch ID references the accelerometer's watch interval, and can be used with accelerometer.clearWatch
to stop watching the accelerometer.
function onSuccess(acceleration) { alert('Acceleration X: ' + acceleration.x + '\n' + 'Acceleration Y: ' + acceleration.y + '\n' + 'Acceleration Z: ' + acceleration.z + '\n' + 'Timestamp: ' + acceleration.timestamp + '\n'); }; function onError() { alert('onError!'); }; var options = { frequency: 3000 }; // Update every 3 seconds var watchID = navigator.accelerometer.watchAcceleration(onSuccess, onError, options);
<!DOCTYPE html> <html> <head> <title>Acceleration Example</title> <script type="text/javascript" charset="utf-8" src="cordova.js"></script> <script type="text/javascript" charset="utf-8"> // The watch id references the current `watchAcceleration` var watchID = null; // Wait for device API libraries to load // document.addEventListener("deviceready", onDeviceReady, false); // device APIs are available // function onDeviceReady() { startWatch(); } // Start watching the acceleration // function startWatch() { // Update acceleration every 3 seconds var options = { frequency: 3000 }; watchID = navigator.accelerometer.watchAcceleration(onSuccess, onError, options); } // Stop watching the acceleration // function stopWatch() { if (watchID) { navigator.accelerometer.clearWatch(watchID); watchID = null; } } // onSuccess: Get a snapshot of the current acceleration // function onSuccess(acceleration) { var element = document.getElementById('accelerometer'); element.innerHTML = 'Acceleration X: ' + acceleration.x + '<br />' + 'Acceleration Y: ' + acceleration.y + '<br />' + 'Acceleration Z: ' + acceleration.z + '<br />' + 'Timestamp: ' + acceleration.timestamp + '<br />'; } // onError: Failed to get the acceleration // function onError() { alert('onError!'); } </script> </head> <body> <div id="accelerometer">Waiting for accelerometer...</div> </body> </html>
The API calls the success callback function at the interval requested, but restricts the range of requests to the device between 40ms and 1000ms. For example, if you request an interval of 3 seconds, (3000ms), the API requests data from the device every 1 second, but only executes the success callback every 3 seconds.