Detecting accelerometer sensor on Symbian C++ (Hourglass)

This code snippet shows how to detect device sensors in Symbian C++.

Article Metadata

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Tested with

Devices(s): Nokia N95

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Article

Created: Diego Soares Lopes (29 Aug 2008)

Last edited: hamishwillee (28 Oct 2011)

07 Sep
2008

Overview

This code snippet shows how to detect device sensors in Symbian C++.

The example taken from an application in which the device accelerometer sensor is used to simulate a real hourglass on the Nokia N95. Every time you change device's position, an observer updates the acceleration values in each axis, ranging from -360 to 360.

Header

 
//SensorApi header
#include <rrsensorapi.h>
 
//CGravitation class inherits an interface MRRSensorDataListener
class CGravitationAppView : public CHourglass,...,MRRSensorDataListener
{
	public:
	   ...
	   //Virtual function inherits from MRRSensorDataListener
	   void  HandleDataEventL (TRRSensorInfo aSensor, TRRSensorEvent aEvent);
	   ...
 
	private:
	   //Instance of CRRSensorApi
	   CRRSensorApi* iSensorApi;

Source

void CGravitationAppView::ConstructL( const TRect& aRect )
{
   ...	
 
   //Creating an array of sensors 
   RArray< TRRSensorInfo > sensorInfoArray;
 
   //Using FindSensorsL to find all sensors in the device and
   //fill the array with the available sensors
   CRRSensorApi::FindSensorsL(sensorInfoArray);
 
   if(sensorInfoArray.Count() > 0)
   {
         //Constructs the iSensorApi with an sensor in the array
         iSensorApi = CRRSensorApi::NewL(sensorInfoArray[1]);
         iSensorApi -> AddDataListener(this);
   }
   else
      User::Leave(KErrNotSupported);
      ...
}
 
CgravitationAppView::~CGravitationAppView()
{
   ...
   //releases memory allocated 
   if(iSensorApi)
   {
      delete iSensorApi;
      iSensorApi = NULL;
   }
 
   ...
}
 
 
//HandleDataEventL's implementation, Callback that updates the acceleration
void CGravitationAppView::HandleDataEventL (TRRSensorInfo aSensor, TRRSensorEvent aEvent)
{
 
   TInt i;
 
   for(i = 0; i < iGrains.Count(); i++)
   {
      iGrains[i]->SetAcelXY(-aEvent.iSensorData2, -aEvent.iSensorData1);
   }
 
}

Application