| --- |
| 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. |
| --- |
| |
| # geolocation.watchPosition |
| |
| Watches for changes to the device's current position. |
| |
| var watchId = navigator.geolocation.watchPosition(geolocationSuccess, |
| [geolocationError], |
| [geolocationOptions]); |
| |
| ## Parameters |
| |
| - __geolocationSuccess__: The callback that is passed the current position. |
| |
| - __geolocationError__: (Optional) The callback that executes if an error occurs. |
| |
| - __geolocationOptions__: (Optional) The geolocation options. |
| |
| ## Returns |
| |
| - __String__: returns a watch id that references the watch position interval. The watch id should be used with `geolocation.clearWatch` to stop watching for changes in position. |
| |
| ## Description |
| |
| `geolocation.watchPosition` is an asynchronous function. It returns |
| the device's current position when a change in position is detected. |
| When the device retrieves a new location, the `geolocationSuccess` |
| callback executes with a `Position` object as the parameter. If |
| there is an error, the `geolocationError` callback executes with a |
| `PositionError` object as the parameter. |
| |
| ## Supported Platforms |
| |
| - Amazon Fire OS |
| - Android |
| - BlackBerry WebWorks 5.0+ |
| - iOS |
| - Tizen |
| - Windows Phone 7 and 8 |
| - Windows 8 |
| |
| ## Quick Example |
| |
| // onSuccess Callback |
| // This method accepts a `Position` object, which contains |
| // the current GPS coordinates |
| // |
| function onSuccess(position) { |
| var element = document.getElementById('geolocation'); |
| element.innerHTML = 'Latitude: ' + position.coords.latitude + '<br />' + |
| 'Longitude: ' + position.coords.longitude + '<br />' + |
| '<hr />' + element.innerHTML; |
| } |
| |
| // onError Callback receives a PositionError object |
| // |
| function onError(error) { |
| alert('code: ' + error.code + '\n' + |
| 'message: ' + error.message + '\n'); |
| } |
| |
| // Options: throw an error if no update is received every 30 seconds. |
| // |
| var watchID = navigator.geolocation.watchPosition(onSuccess, onError, { timeout: 30000 }); |
| |
| ## Full Example |
| |
| <!DOCTYPE html> |
| <html> |
| <head> |
| <title>Device Properties Example</title> |
| |
| <script type="text/javascript" charset="utf-8" src="cordova.js"></script> |
| <script type="text/javascript" charset="utf-8"> |
| |
| // Wait for device API libraries to load |
| // |
| document.addEventListener("deviceready", onDeviceReady, false); |
| |
| var watchID = null; |
| |
| // device APIs are available |
| // |
| function onDeviceReady() { |
| // Throw an error if no update is received every 30 seconds |
| var options = { timeout: 30000 }; |
| watchID = navigator.geolocation.watchPosition(onSuccess, onError, options); |
| } |
| |
| // onSuccess Geolocation |
| // |
| function onSuccess(position) { |
| var element = document.getElementById('geolocation'); |
| element.innerHTML = 'Latitude: ' + position.coords.latitude + '<br />' + |
| 'Longitude: ' + position.coords.longitude + '<br />' + |
| '<hr />' + element.innerHTML; |
| } |
| |
| // onError Callback receives a PositionError object |
| // |
| function onError(error) { |
| alert('code: ' + error.code + '\n' + |
| 'message: ' + error.message + '\n'); |
| } |
| |
| </script> |
| </head> |
| <body> |
| <p id="geolocation">Watching geolocation...</p> |
| </body> |
| </html> |
