From Forum Nokia Wiki

ID		Creation date	November 02, 2008
Platform	S60 5th Edition	Tested on devices
Category	Symbian C++	Subcategory

Keywords (APIs, classes, methods, functions): Accessory Monitoring API, CAccMonitor, RConnectedAccessories, CAccMonitorInfo, KAccMonHeadset, KAccMonWired

The Accessory Monitoring API interface offers accessory information about connected accessories. This API is meant to be used by clients that need to access information about connected accessories or clients that need notifications about accessories that connect/disconnect to the device. This API can be accessed by all S60 clients. The API provides stand-alone implementation units that are used by the client and the API provides information about the devices hardware resources.

Overview

Accessory connected/disconnected notifications can be listened with the StartListeningL() method of the CAccMonitor. Connection notifications in client side are received from the MAccMonitorObserver class. Thus client must implement this interface. Connection notifications are received through the ConnectedL() method and disconnection notifications are received through the DisconnectedL() method.

One of the use case of handling connected/disconnected notifications is sending application background/foreground on connection/disconnection events correspondingly. For example, music player application could be brought to foreground on headset connection event.

MMP file

LIBRARY accmonitor.lib
CAPABILITY could be self-signed

Header file

#include <accmonitor.h>
...
class CAccMonitorTest: public MAccMonitorObserver, ...
   {
   ...
   public:
   CAccMonitorTest();
   void ConstructL();
 
   private:
   void ConnectedL(CAccMonitorInfo* aAccessoryInfo);
   void DisconnectedL(CAccMonitorInfo* aAccessoryInfo);
 
   private:
   // Instance of the connected accessory. The content of the pointer passed to  ConnectedL()/DisconnectedL() must be copied to this value (with CopyL()),
   // because the original pointer is distroyed after mentioned methods have been called.
   CAccMonitorInfo* iAccessoryInfo;
   };

Source file

Start listening of headset connected/disconnected notifications:

void CAccMonitorTest::ConstructL()
   {
   ...
   CAccMonitor* accMonitor = CAccMonitor::NewLC();
   RConnectedAccessories array;
   CleanupClosePushL(array);
   accMonitor->GetConnectedAccessoryL(array);
 
   if(accMonitor->IsObserving())
	{
        // Iterate through available accessories
        for (TInt i = 0; count != i; i++)
		{
		if( array[i]->AccDeviceType() == KAccMonHeadset)
			{
			// Start observing of headset connected/disconnected notifications
			accMonitor->StartObservingL(this, array[i]);
			break;
			}
		}
  	}
 
   CleanupStack::PopAndDestroy(&array);
   CleanupStack::PopAndDestroy(accMonitor);
   ...
   }

Handling connected/disconnected notifications:

void CAccMonitorTest::ConnectedL(CAccMonitorInfo* aAccessoryInfo)
    {
    // Reserve memory for the accessory information instance if necessary
    if (!iAccessoryInfo)
       iAccessoryInfo = CAccMonitorInfo::NewL();
    // Otherwise just reset accessory information instance
    else
       iAccessoryInfo->Reset();
 
    iAccessoryInfo->CopyL(aAccessoryInfo);
 
    // Bring application to foreground
    if (iAccessoryInfo->AccDeviceType() == KAccMonHeadset)
    {
       TApaTask task(CEikonEnv::Static()->WsSession());               
       task.SetWgId(CEikonEnv::Static()->RootWin().Identifier());    
       task.BringToForeground();    
    }
    }
...
void CAccMonitorTest::DisconnectedL(CAccMonitorInfo*  aAccessoryInfo)
   {
   // Reserve memory for the accessory information instance if necessary
   if (!iAccessoryInfo)
      iAccessoryInfo = CAccMonitorInfo::NewL();
   // Otherwise just reset accessory information instance
   else
      iAccessoryInfo->Reset();
 
   iAccessoryInfo->CopyL(aAccessoryInfo);
 
   // Send application to background
   if (iAccessoryInfo->AccDeviceType() == KAccMonHeadset)
   {
      TApaTask task(CEikonEnv::Static()->WsSession());               
      task.SetWgId(CEikonEnv::Static()->RootWin().Identifier());    
      task.SendToBackground();    
   }
   }

Postconditions

Specific accessory connected/disconnected notifications have been handled.