查看是否有GPS设备。并且获取设备的ID

需要下列能力和链接库CAPABILITY Location  
LIBRARY Lbs.lib
头文件#include <lbs.h>

 //查看是否有GPS设备。
 TPositionModuleId CYourClass::GetPositionModuleId()
     {
     TInt error = KErrNone;


     RPositionServer ps; // TODO: Move to the class member variable
     error = ps.Connect();
     if (error != KErrNone)
         {
         return KNullUid;
         }


     TUint numModules = 0;
     error = ps.GetNumModules(numModules);
     if (error != KErrNone)
         {
         ps.Close(); // TODO: No need to close RPositionServer if it is moved
                     // to class member variable, then it must close in class
                     // destructor.
         return KNullUid;
         }


     TPositionModuleId currentModuleId = KNullUid;
     TPositionModuleId selectedModuleId = KNullUid;
     for (TInt moduleIndex = 0; moduleIndex < numModules; moduleIndex++)
         {
         TPositionModuleInfo moduleInfo;
         error = ps.GetModuleInfoByIndex(moduleIndex, moduleInfo);
         if (error != KErrNone)
             {
             ps.Close(); // TODO: No need to close RPositionServer if it is
                         // moved to class member variable, then it must close
                         // in class destructor.
             return selectedModuleId;
             }


         currentModuleId = moduleInfo.ModuleId();


         TPositionModuleStatus moduleStatus;
         error = ps.GetModuleStatus(moduleStatus, currentModuleId);
         if (error != KErrNone ||
         moduleStatus.DeviceStatus() == TPositionModuleStatus::EDeviceDisabled)
             {
             continue;
             }


         TPositionModuleInfo::TDeviceLocation deviceLoc =
             moduleInfo.DeviceLocation();
         if (deviceLoc == TPositionModuleInfo::EDeviceInternal)
             {
             if (selectedModuleId == KNullUid)
                 {
                 // Found first internal position module, select that
                 selectedModuleId = currentModuleId;
                 }
             else
                 {
                 // Check external module should be switched to internal
                 TPositionModuleInfo selectedModuleInfo;
                 error = ps.GetModuleInfoById(selectedModuleId,
                     selectedModuleInfo);
                 if (error == KErrNone && selectedModuleInfo.DeviceLocation()
                 == TPositionModuleInfo::EDeviceExternal)
                     {
                     // Change external device to internal
                     selectedModuleId = currentModuleId;
                     }
                 }
             }
         else if (deviceLoc == TPositionModuleInfo::EDeviceExternal)
             {
             // Just pick the first external device, if none is currently
             // selected
             if (selectedModuleId == KNullUid)
                 {
                 // Found first enternal position module, select that
                 selectedModuleId = currentModuleId;
                 }
             }
         }


     ps.Close(); // TODO: No need to close RPositionServer if it is moved to
                 // class member variable, then it must close in class
                 // destructor.
     return selectedModuleId;
     }





 // Use selected GPS device
 void CYourClass::OpenPositioner(TPositionModuleId aDevice)
     {
     RPositioner positioner;    // TODO: Move to the class member variable
     RPositionServer ps;        // TODO: Move to the class member variable


     if (aDevice != KNullUid)
         {
         if (ps.Connect() == KErrNone)
             {
             // Selected GPS device goes as 'aDevice' parameter
             positioner.Open(ps,aDevice);
             positioner.Close();
             ps.Close();
             }
         }
     }