Sensor Service API example

This section presents the full source code of a working sample widget +for the Sensor Service. +You can download the wgz package for this widget from +section Example widgets.

For general information about creating widgets, see section Widget component files.

For widget development and debugging purposes, this example writes its +output to c:\data\jslog_widget.log using console.info. +For instructions on how to enable logging in the Web browser for S60, see +section JavaScript console.

Info.plist

<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Nokia//DTD PLIST 1.0//EN" "http://www.nokia.com/NOKIA_COM_1/DTDs/plist-1.0.dtd">
+<plist version="1.0">
+<dict>
+  <key>DisplayName</key>
+  <string>SensorSample</string>
+  <key>Identifier</key>
+  <string>com.nokia.widget.sapi.sensor.sample</string>
+  <key>Version</key>
+  <string>1.0</string>
+  <key>MainHTML</key>
+  <string>sensor-sample.html</string>
+</dict>
+</plist>

sensor-sample.html

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
+<html>
+  <head>
+    <script type="text/javascript" src="js/common.js"></script>
+    <script type="text/javascript" src="js/sensor-sample.js" charset="utf-8"></script>
+  </head>
+  <body onload='setup()' bgcolor="#ddeeff">
+    <form name="frm">
+      <h3>Sapi Sensor Sample Widget</h3>
+      <input type="button" onclick="findSensorChannel('img1')" value="FindSensorChannel"><img id="img1" src="pic/blank.png" width="25" height="25" align="center"><br>
+      <input type="button" onclick="getChannelProperty('img2')" value="GetChannelProperty"><img id="img2" src="pic/blank.png" width="25" height="25" align="center"><br>
+      <input type="button" onclick="setChannelProperty('img3')" value="RegisterForNotification"><img id="img5" src="pic/blank.png" width="25" height="25" align="center"><br>
+      <input type="button" onclick="stopReceivingNotification('img6')" value="Cancel"><img id="img6" src="pic/blank.png" width="25" height="25" align="center"><hr>
+      <div class='sensor' id='sensor' bgcolor="#ddeeff" style=width:100%;height:100%;overflow:auto></div>
+    </form>
+  </body>
+</html>
+

common.js

// common.js
+//
+// This file contains some utility functions
+
+// Check the error code and show the information to users
+function checkError(message, resultList, divId, imgId)
+{
+  var errCode = resultList.ErrorCode;
+  var msg = "";
+  
+  if (errCode) {
+    msg = message + "<BR>" + "Failed Error: " + errCode + "<BR>";
+    if(resultList.ErrorMessage != undefined)
+      msg += "Error Message: " + resultList.ErrorMessage;
+    showIMG(imgId,"no"); 
+  } else {
+    showIMG(imgId,"yes"); 
+  }
+
+  //print error message
+  if(divId != null && divId != undefined)
+    document.getElementById(divId).innerHTML = msg;
+  console.info(msg);
+  
+  return errCode;
+}
+
+// Build the message by reading a iteratorable list in a recursive manner
+function showIterableList(iterator)
+{
+  var msg = "";
+  try
+  {
+    iterator.reset();
+    var item;
+    while (( item = iterator.getNext()) != undefined ){
+      msg += showObject( item );
+    }
+  }
+  catch(e)
+  {
+    alert('<showIterableList> ' + e);
+  }
+  return msg;
+}
+
+// Build the message by reading a JS object in a recursive manner
+function showObject( obj )
+{
+  var txt = "";
+  try { 
+    if ( typeof obj != 'object' )
+      return "" + obj + '<BR/>';
+    else {
+      for(var key in obj) {
+        txt +=  key + ":";
+        txt += showObject( obj[key] );
+        txt += '<BR/>';
+      }
+      txt += '<BR/>';
+    }
+  } 
+  catch (e) 
+  {
+    alert("showObject: " + e);
+  }
+  return txt;
+}
+
+// Show the image to indicate the test result
+function showIMG(imgId, isOK) 
+{
+  if(imgId == null || imgId == undefined)
+    return;
+  
+  if(isOK == "yes")
+    document.getElementById(imgId).src = "pic/yes.png";
+  else if(isOK == "no")
+    document.getElementById(imgId).src = "pic/no.png";
+  else
+    document.getElementById(imgId).src = "pic/blank.png";
+}
+
+// Show elements in object by using 'alert'
+function testObject(obj)
+{
+  var msg = "";
+  for(var key in obj) {
+    msg = msg + ":" + key + "=" + obj[key];
+  }
+  alert(msg);
+}
+
+// Test whether the input is numeric
+function IsNumeric(sText)
+{
+  var ValidChars = "0123456789.";
+  var IsNumber=true;
+  var Char;
+  
+  for (i = 0; i < sText.length && IsNumber == true; i++) 
+  { 
+    Char = sText.charAt(i); 
+    if (ValidChars.indexOf(Char) == -1) 
+    {
+      IsNumber = false;
+    }
+  }
+  return IsNumber; 
+}

sensor-sample.js

// sensor-sample.js
+//
+// In this sample the sensor will be found, get and set;
+// Also, async operation will be canceled.
+//
+
+// SAPI Error Codes
+// 0  - Success
+// 1000 - InvalidServiceArgument
+// 1001 - UnknownArgumentName
+// 1002 - BadArgumentType
+// 1003 - MissingArgument
+// 1004 - ServiceNotSupported
+// 1005 - ServiceInUse
+// 1006 - ServiceNotReady
+// 1007 - NoMemory
+// 1008 - HardwareNotAvailable
+// 1009 - ServerBusy
+// 1010 - EntryExists
+// 1011 - AccessDenied
+// 1012 - NotFound
+// 1013 - UnknownFormat
+// 1014 - GeneralError
+// 1015 - CancelSuccess
+// 1016 - ServiceTimedOut
+// 1017 - PathNotFound
+
+// Usage:
+// 1. Call FindSensorChannel (input searchCriterion) - this call obtains a list of maps.The list can be fetched using the key : ReturnValue
+// 2. From the list you need to fetch one ChannelInfo as a map.The fetching depends on how the runtime fetches items from an CLiwDefaultList.
+// 3. It is this ChannelInfo map that needs to be supplied to all the other APIs that follow.
+ 
+// Declare the service object
+var so;
+
+// imgid for callback1 function
+var imgid_callback1;
+
+// id of the div used to display information
+const DIV_ID = 'sensor';
+
+// transaction id
+var transactionID;
+
+// Called from onload()
+function setup()
+{
+  try {
+    so = device.getServiceObject("Service.Sensor", "ISensor");
+    console.info("setup: so: %s", so);
+  }
+  catch (e) {
+    alert('<setup> ' +e);
+  }
+}
+
+//FindSensorChannel - searches and list available sensor channels.
+function findSensorChannel(imgId)
+{
+  var criteria = new Object();
+  criteria.SearchCriterion = "Rotation";
+
+  try
+  {
+    var result = so.ISensor.FindSensorChannel(criteria);
+    if(!checkError("ISensor::findSensorChannel",result,DIV_ID,imgId)) {
+      document.getElementById(DIV_ID).innerHTML = showIterableList(result.ReturnValue);
+    }
+  }
+  catch (e)
+  {
+    showIMG(imgId,"no");
+    alert ("findSensorChannel: " + e);
+  }
+}
+
+// GetChannelProperty
+function getChannelProperty(imgId)
+{
+  var channelInfoMap = new Object();
+  channelInfoMap.ChannelId = 1;
+  channelInfoMap.ContextType = 0;  // 0-not defined; 1- to measure pressure, ...
+  channelInfoMap.Quantity = 0;
+  channelInfoMap.ChannelType = 0 ;
+
+  var criteria = new Object();
+  criteria.PropertyId = "Description";
+  criteria.ChannelInfoMap = channelInfoMap;
+
+  try
+  {
+    var result = so.ISensor.GetChannelProperty(criteria);
+    if(!checkError("ISensor::getChannelProperty",result,DIV_ID,imgId)) {
+      document.getElementById(DIV_ID).innerHTML = showIterableList(result.ReturnValue);
+    }
+  }
+  catch (e)
+  {
+    showIMG(imgId,"no");
+    alert ("getChannelProperty: " + e);
+  }
+}
+
+// RegisterForNotification - register to receive
+// notification about channel data.
+function registerForNotification(imgId)
+{
+  var channelInfoMap = new Object();
+  channelInfoMap.ChannelId = 1;
+  channelInfoMap.ContextType = 0;  // 0-not defined; 1- to measure pressure, ...
+  channelInfoMap.Quantity = 0;
+  channelInfoMap.ChannelType = 0 ;
+
+  var criteria = new Object();
+  criteria.ListeningType = "ChannelData";
+  criteria.ChannelInfoMap = channelInfoMap;
+
+  try
+  {
+    imgid_callback1 = imgId
+    var result = so.ISensor.RegisterForNotification(criteria, callback1);
+    transactionID = result.TransactionID;
+    if(!checkError("ISensor::registerForNotification",result,DIV_ID,imgId)){
+      showIMG(imgId,"");
+    }
+  }
+  catch (e)
+  {
+    showIMG(imgId,"no");
+    alert ("registerForNotification: " + e);
+  }
+}
+
+//Cancel Notification
+function Cancel(imgId)
+{
+  var criteria = new Object();
+  criteria.TransactionID = transactionID;
+  try
+  {
+    var result = so.ISensor.Cancel(criteria);
+    checkError("ISensor::Cancel",result,DIV_ID,imgId)
+  }
+  catch (e)
+  {
+    showIMG(imgId,"no");
+    alert ("Cancel: " + e);
+  }
+}
+
+// This is the asynchronous callback handler
+function callback1(transId, eventCode, result)
+{
+  console.info("callback1: transId: %d  eventCode: %d result.ErrorCode: %d", transId, eventCode, result.ErrorCode);
+  if(!checkError("ISensor::registerForNotification",result,DIV_ID,imgid_callback1)) {
+    document.getElementById(DIV_ID).innerHTML = "Channel Property changes";
+  }
+}