| --- |
| 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. |
| --- |
| |
| accelerometer.watchAcceleration |
| =============================== |
| |
| At a regular interval, get the acceleration along the _x_, _y_, and _z_ axis. |
| |
| var watchID = navigator.accelerometer.watchAcceleration(accelerometerSuccess, |
| accelerometerError, |
| [accelerometerOptions]); |
| |
| Description |
| ----------- |
| |
| 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. |
| |
| Supported Platforms |
| ------------------- |
| |
| - Android |
| - BlackBerry WebWorks (OS 5.0 and higher) |
| - iOS |
| - Tizen |
| - Windows Phone 7 and 8 |
| - Windows 8 |
| |
| Quick Example |
| ------------- |
| |
| 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); |
| |
| Full Example |
| ------------ |
| |
| <!DOCTYPE html> |
| <html> |
| <head> |
| <title>Acceleration Example</title> |
| |
| <script type="text/javascript" charset="utf-8" src="cordova-x.x.x.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> |
| |
| iOS Quirks |
| ------------- |
| |
| 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. |
