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Archived:Displaying sensor data on Symbian

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[[Category:Symbian C++]][[Category:Code Snippet]][[Category:Hardware]][[Category:Sensor]][[Category:S60 3rd Edition (initial release)]][[Category:Code Snippet]]

Revision as of 04:25, 19 June 2012

Archived.pngArchived: This article is archived because it is not considered relevant for third-party developers creating commercial solutions today. If you think this article is still relevant, let us know by adding the template {{ReviewForRemovalFromArchive|user=~~~~|write your reason here}}.

Article Metadata
Tested with
Devices(s): Nokia N95 8GB
Platform(s): S60 3rd Edition, MR
S60 3rd Edition (initial release)
Keywords: MRRSensorDataListener, TRRSensorInfo, TRRSensorEvent, CFont, CWindowGc, MRRSensorDataListener::HandleDataEventL(), CGraphicsDevice::GetNearestFontInTwips(), CWindowGc::SetBrushColor(), CWindowGc::UseFont(), CWindowGc::DrawText()
Created: tapla (17 Apr 2008)
Last edited: hamishwillee (19 Jun 2012)



This code snippet demonstrates how to display the data produced by the accelerometer and rotation sensors of the device on the screen.

Registering listeners for the sensors is not covered in this code snippet. See Listening for accelerometer sensor data events on Symbian and Listening for rotation sensor data events on Symbian for more information on registering listeners.

Note: In order to use the code, you need to install the sensor plug-in for your SDK.

This snippet can be self-signed.

MMP file

The following libraries are required:

LIBRARY RRSensorApi.lib
LIBRARY gdi.lib

Header file

#include <coecntrl.h>   // CCoeControl
#include <gdi.h> // CFont
#include <RRSensorApi.h>
// Accelerometer sensor UID
const TInt KAccelerometerSensorUID = 0x10273024;
// Rotation sensor UID
const TInt KRotationSensorUID = 0x303E;
class CMyControl : public CCoeControl, public MRRSensorDataListener
// ...
private: // Functions from base classes
* From CCoeControl.
* Draws this control to the screen.
* @param aRect the rectangle of this view that needs updating

void Draw(const TRect& aRect) const;
* From MRRSensorDataListener.
* Callback function for receiving sensor data events.
* @param aSensor identifies the sensor that created the event.
* @param aEvent contains data about created event.

void HandleDataEventL(TRRSensorInfo aSensor, TRRSensorEvent aEvent);
private: // Data
CRRSensorApi* iAccelerometerSensor;
TInt iAccSensorDataX;
TInt iAccSensorDataY;
TInt iAccSensorDataZ;
CRRSensorApi* iRotationSensor;
TInt iRotSensorDataX;
TInt iRotSensorDataY;
TInt iRotSensorDataZ;
CFont* iFont;

Source file

#include <EIKENV.H> // CEikonEnv
#include <gdi.h> // TFontSpec, CGraphicsDevice
#include <RRSensorApi.h>
void CMyControl::ConstructL(const TRect& aRect)
// ...
// Reset sensor data
iAccSensorDataX = 0;
iAccSensorDataY = 0;
iAccSensorDataZ = 0;
iRotSensorDataX = 0;
iRotSensorDataY = 0;
iRotSensorDataZ = 0;
// Initialize the font used in drawing onto the screen
_LIT(KFontName, "Arial");
const TInt KFontSize = 120;
TFontSpec fontSpec(KFontName, KFontSize);
CGraphicsDevice* screenDevice = CEikonEnv::Static()->ScreenDevice();
screenDevice->GetNearestFontInTwips(iFont, fontSpec);
// ...
* Draws the display.

void CMyControl::Draw(const TRect& /*aRect*/) const
// Get the standard graphics context
CWindowGc& gc = SystemGc();
// Get the control's extent
TRect drawRect(Rect());
// Clear the screen with white color
// Set the font
// The text is drawn in black
TBuf<255> buffer;
// Draw accelerometer sensor data
_LIT(KAccTxt, "Accel. sensor: X: %d, Y: %d, Z: %d");
buffer.Format(KAccTxt, iAccSensorDataX, iAccSensorDataY, iAccSensorDataZ);
gc.DrawText(buffer, TPoint(0, 20));
// Draw rotation sensor data
_LIT(KRotTxt, "Rotation sensor: X: %d, Y: %d, Z: %d");
buffer.Format(KRotTxt, iRotSensorDataX, iRotSensorDataY, iRotSensorDataZ);
gc.DrawText(buffer, TPoint(0, 40));
* Gets called whenever a data event occurs.

void CMyControl::HandleDataEventL(TRRSensorInfo aSensor, TRRSensorEvent aEvent)
// A data event occurred. Store new values from the sensor in question.
switch (aSensor.iSensorId)
case KAccelerometerSensorUID:
iAccSensorDataX = aEvent.iSensorData1;
iAccSensorDataY = aEvent.iSensorData2;
iAccSensorDataZ = aEvent.iSensorData3;
case KRotationSensorUID:
iRotSensorDataX = aEvent.iSensorData1;
iRotSensorDataY = aEvent.iSensorData2;
iRotSensorDataZ = aEvent.iSensorData3;
// Update the display


Data received from accelerometer and rotation sensors is constantly drawn onto the screen.

See also

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