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GPS and Web Service using C++ ATL/WTL (Windows Mobile 6, Standard)

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18 Jan 2008CPOL7 min read 104.7K   1.4K   81  
This article explains how to use the GPS API and Web Service on a SmartPhone to show demographics information for the current location.
#include "StdAfx.h"
#include "GPSDevice.h"

CGPSDevice * CGPSDevice::s_pInstance = NULL;

#define MAX_WAIT    5000
#define MAX_AGE     3000
#define GPS_CONTROLLER_EVENT_COUNT 3

CGPSDevice::CGPSDevice(void)
{
	m_pSink = NULL;
	m_hGPS_Device = NULL;
	m_hNewLocationData = NULL;
	m_hDeviceStateChange = NULL;
	m_hExitThread = NULL;
}

CGPSDevice::~CGPSDevice(void)
{
}

CGPSDevice * CGPSDevice::Instance()
{
	if( CGPSDevice::s_pInstance == NULL )
	{
		s_pInstance = new CGPSDevice();
	}

	return CGPSDevice::s_pInstance;
}

DWORD WINAPI CGPSDevice::GPSThreadProc(__opt LPVOID lpParameter)
{
    DWORD dwRet = 0;
    GPS_POSITION gps_Position = {0};
    GPS_DEVICE gps_Device = {0};
    

	CGPSDevice * pDevice = (CGPSDevice*) lpParameter;

	HANDLE gpsHandles[GPS_CONTROLLER_EVENT_COUNT] = 
	{	pDevice->m_hNewLocationData, 
        pDevice->m_hDeviceStateChange,
        pDevice->m_hExitThread
    };

    gps_Position.dwSize = sizeof(gps_Position);
    gps_Position.dwVersion = GPS_VERSION_1;

    gps_Device.dwVersion = GPS_VERSION_1;
    gps_Device.dwSize = sizeof(gps_Device);

    do
    {
        dwRet = WaitForMultipleObjects(
			GPS_CONTROLLER_EVENT_COUNT, 
			gpsHandles, FALSE, INFINITE);

        if (dwRet == WAIT_OBJECT_0)
        {
            dwRet = GPSGetPosition(
				pDevice->m_hGPS_Device, 
				&gps_Position, MAX_AGE, 0);

            if (ERROR_SUCCESS != dwRet)
                continue;
            else
				pDevice->m_pSink->SetGPSPosition(gps_Position);
        }
        else if (dwRet == WAIT_OBJECT_0 + 1)
        {
            dwRet = GPSGetDeviceState(&gps_Device);	

            if (ERROR_SUCCESS != dwRet)
                continue;
            else
                pDevice->m_pSink->SetGPSDeviceInfo(gps_Device);
        }
        else if (dwRet == WAIT_OBJECT_0 + 2)
            break;
        else
            ASSERT(0);
    
	} while( TRUE );

	return 0;
}

HRESULT CGPSDevice::StartThread()
{
	HRESULT hr = E_FAIL;
	DWORD dwRet = 0;

	m_hNewLocationData = CreateEvent(NULL, FALSE, FALSE, NULL);

	if ( m_hNewLocationData )
	{
		m_hDeviceStateChange = CreateEvent(NULL, FALSE, FALSE, NULL);
		
		if (m_hDeviceStateChange)
		{

			m_hExitThread = CreateEvent(NULL, FALSE, FALSE, NULL);
			if (m_hExitThread)
			{
				
				m_hThread = ::CreateThread(NULL, NULL, 
					GPSThreadProc, this, NULL, &m_dwThreadID);
				
				if ( m_hThread )
					hr = S_OK;
			}
		}
	}

	if( FAILED(hr) )
	{
		dwRet = GetLastError();
		hr = HRESULT_FROM_WIN32(dwRet);
	}

	if (FAILED(hr))
	{
		if (m_hNewLocationData)
		{
			CloseHandle(m_hNewLocationData);
			m_hNewLocationData = NULL;
		}

		if (m_hDeviceStateChange)
		{
			CloseHandle(m_hDeviceStateChange);
			m_hDeviceStateChange = NULL;
		}

		if (m_hExitThread)
		{
			CloseHandle(m_hExitThread);
			m_hExitThread = NULL;
		}
	}
	return hr;	
}

HRESULT CGPSDevice::StopThread()
{
    HRESULT hr = E_FAIL;
    DWORD dwRet = 0;

    if( SetEvent(m_hExitThread) )
    {
		dwRet = WaitForSingleObject(m_hThread, MAX_WAIT);
		if(WAIT_OBJECT_0 == dwRet)
			hr = S_OK;
	}

	if( FAILED(hr) )
	{
        dwRet = GetLastError();
        hr = HRESULT_FROM_WIN32(dwRet);
	}

	if (m_hNewLocationData)
    {
        CloseHandle(m_hNewLocationData);
        m_hNewLocationData = NULL;
    }

    if (m_hDeviceStateChange)
    {
        CloseHandle(m_hDeviceStateChange);
        m_hDeviceStateChange = NULL;
    }

    if (m_hExitThread)
    {
        CloseHandle(m_hExitThread);
        m_hExitThread = NULL;
    }

    if (m_hThread)
    {
        CloseHandle(m_hThread);
        m_hThread = NULL;
		m_dwThreadID = 0;
    }

    return hr;
}

HRESULT CGPSDevice::TurnOn(IGPSSink * pSink)
{
	if( !pSink )
		return E_INVALIDARG;

	CGPSDevice * pDevice = Instance();

	//We already have a device opened
	if( pDevice->m_hGPS_Device )
		return E_UNEXPECTED;

	if( pDevice->m_pSink != NULL )
		return E_UNEXPECTED;

	pDevice->m_pSink = pSink;

	HRESULT hr = pDevice->StartThread();

	if( SUCCEEDED(hr) )
	{
		pDevice->m_hGPS_Device = GPSOpenDevice( 
			pDevice->m_hNewLocationData, 
			pDevice->m_hDeviceStateChange, 
			NULL, NULL);

		if( pDevice->m_hGPS_Device )
			hr = S_OK;
		else
			hr = HRESULT_FROM_WIN32(GetLastError());
	}

	if( FAILED(hr) )
		TurnOff();

	return hr;
}

HRESULT CGPSDevice::TurnOff()
{
	CGPSDevice * pDevice = Instance();

	if( !pDevice->m_hGPS_Device )
		return E_UNEXPECTED;	

	HRESULT hr = pDevice->StopThread();


	pDevice->m_pSink = NULL;

	DWORD dwRet = GPSCloseDevice(pDevice->m_hGPS_Device);
    pDevice->m_hGPS_Device = NULL;

	if( SUCCEEDED(hr) )
	{
		if( ERROR_SUCCESS != dwRet )
	        hr = HRESULT_FROM_WIN32(GetLastError());
	}

	return hr;
}

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License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)


Written By
Chief Technology Officer CDYNE Corporation
United States United States
Developer, Maker and Tinkerer

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