Hi
I want to make a call with my mda without using the RAS dialer. Direct access to the COM-ports does not work, as described in the document "Serial Communications". But that documents mentions that TAPI calls are possible with an xda.
It says:
"If you´ve establised a call, TAPI returns a handle for further data-i/o..."
Is there an example how to make a call using TAPI especially how to get that data-handle. And furthermore can I use that handle with WriteFile / ReadFile as I would use a handle to a COM-Port?
I did this for a terminal emulator I wrote. I pass a string to these functions which is COM1: for serial, TAPI for modem or RAS for TCPIP RAS.
I have simply copied some of my code here, work through it as if lpszPortName = "TAPI" and you should make sense of it. Once you have the port handle hPort which is returned by the Connected response of the TAPI call back function, then you can read and write as if that were a serial/file handle.
Cheers
Paul
#include <windows.h>
#include <string.h>
#include <tapi.h>
#include "toolbox.h"
//Initilise the port either the TAPI or COMM port as requested by lpszPortName
BOOL PortInitialize (LPTSTR lpszPortName)
{
DWORD dwError;
BOOL RetValue;
HKEY hKey;
DWORD RegKeyDisp, RegKeyType, RegKeySize;
DWORD dwTapiNumDevs;
LONG lTapiReturn;
char PrintString[80];
TCHAR TempString[20];
char CharString[20];
LINEDEVCAPS TapiLineDevCaps;
static DWORD dwLocalAPIVersion;
LINEEXTENSIONID LineExtensionID;
LINECALLPARAMS LineCallParams;
static DWORD ChoosenDevice;
TCHAR DialNumber[30];
#ifdef _WIN32_WCE_EMULATION
if (wcscmp(lpszPortName, TEXT("TAPI")) != 0)
return TRUE; //If running under emulator then unable to emulate
#endif //the serial port, so in this 'test' mode just echo.
if (COMMPORTSHUT == TRUE) //If this is True then we are shutting down the program
return TRUE; //So don't try to re-open port as it gets stuck in an infinate loop
if (wcscmp(lpszPortName, TEXT("TAPI")) == 0)
{
#ifdef DEBUGVERSION
VTPrint("Entering (TAPI)PortInitilize\r\n" , 0);
#endif
//Retrive the telephone number from the registry
// Fill in the Modem Telephone number
wcscpy(DialNumber, TEXT("T"));
if (RegCreateKeyEx(HKEY_LOCAL_MACHINE,
TEXT("Software\\PVG\\Terminal\\Settings"),
0, NULL, 0,0, NULL, &hKey, &RegKeyDisp) == ERROR_SUCCESS)
{
//Retrive the telephone number
RegKeyType = REG_SZ;
RegKeySize = sizeof(DialNumber);
RegQueryValueEx(hKey, TEXT("Telephone"),
NULL, &RegKeyType,
(PBYTE)DialNumber + sizeof(TCHAR),
&RegKeySize);
RegCloseKey(hKey);
}
//Confirm there is a telephone number
if (*(DialNumber + 1) == 0)
{
VTPrint("No Telephone Number\r\n", 0);
return FALSE;
}
// Use TAPI to open a DATAMODEM communication channel
if (ghLineApp == NULL)
{
#ifdef DEBUGVERSION
VTPrint("Tapi - LineInitialise\r\n",0);
#endif
memset(&TapiLineDevCaps, 0, sizeof(TapiLineDevCaps));
lTapiReturn = lineInitialize(&ghLineApp, hInst, TapiCallBackFunction, NULL, &dwTapiNumDevs);
if (lTapiReturn)
{
wsprintf (TempString,TEXT("%d"), lTapiReturn);
WideCharToMultiByte(CP_ACP, 0, TempString, -1, CharString, 20, NULL, NULL);
VTPrint("TAPI failed to initialise\n\rError Code = ",0);
VTPrint(CharString, 0);
VTPrint("\n\r",0);
TAPIShutdown();
return FALSE;
}
//Loop through devices to find one that can do data at 9600 baud (GSM)
for (ChoosenDevice=0 ; ChoosenDevice < dwTapiNumDevs ; ChoosenDevice++)
{
TapiLineDevCaps.dwTotalSize = sizeof(TapiLineDevCaps);
//Ask for at least TAPI Version 1.4
lTapiReturn = lineNegotiateAPIVersion(ghLineApp, ChoosenDevice, 0x00010004,
0x00010004, &dwLocalAPIVersion, &LineExtensionID);
#ifdef DEBUGVERSION
if (lTapiReturn)
{
wsprintf (TempString,TEXT("%d"), lTapiReturn);
WideCharToMultiByte(CP_ACP, 0, TempString, -1, CharString, 20, NULL, NULL);
VTPrint("TAPI failed to negotiate API Version\n\rError Code = ",0);
VTPrint(CharString, 0);
VTPrint("\n\r",0);
}
#endif
if (!(lTapiReturn))
{
lTapiReturn=lineGetDevCaps(ghLineApp, ChoosenDevice, dwLocalAPIVersion, 0, &TapiLineDevCaps);
#ifdef DEBUGVERSION
if (lTapiReturn)
{
wsprintf (TempString,TEXT("%d"), lTapiReturn);
WideCharToMultiByte(CP_ACP, 0, TempString, -1, CharString, 20, NULL, NULL);
VTPrint("TAPI failed to get device capibility\n\rError Code = ",0);
VTPrint(CharString, 0);
VTPrint("\n\r",0);
}
else
#endif
#ifndef DEBUGVERSION
if (!(lTapiReturn))
#endif
{
if ((TapiLineDevCaps.dwBearerModes & LINEBEARERMODE_VOICE) &&
(TapiLineDevCaps.dwMaxRate >= 9600) &&
(TapiLineDevCaps.dwMediaModes & LINEMEDIAMODE_DATAMODEM))
break;
}
}
}
if (!((TapiLineDevCaps.dwBearerModes & LINEBEARERMODE_VOICE) ||
(TapiLineDevCaps.dwMaxRate >= 9600) ||
(TapiLineDevCaps.dwMediaModes & LINEMEDIAMODE_DATAMODEM)))
{
VTPrint("Unable to find a modem device\r\n", 0);
TAPIShutdown();
lineShutdown(ghLineApp);
ghLineApp = NULL;
return FALSE;
}
//Now we have found a device capable of a dial up modem
strcpy(PrintString, "TAPI Initilised (");
wsprintf (TempString,TEXT("%d"), ChoosenDevice);
WideCharToMultiByte(CP_ACP, 0, TempString, -1, CharString, 20, NULL, NULL);
strcat(PrintString, CharString);
strcat(PrintString, "/");
wsprintf (TempString,TEXT("%d"), dwTapiNumDevs);
WideCharToMultiByte(CP_ACP, 0, TempString, -1, CharString, 3, NULL, NULL);
strcat(PrintString, CharString);
strcat(PrintString, ")\n\r");
VTPrint(PrintString, 0);
}
//Open the TAPI line device
if (ghLine == NULL)
{
#ifdef DEBUGVERSION
VTPrint("TAPI - Obtaining line handle\r\n", 0);
#endif
lTapiReturn = lineOpen(ghLineApp, ChoosenDevice, &ghLine, dwLocalAPIVersion, 0 , 0,
LINECALLPRIVILEGE_NONE, LINEMEDIAMODE_DATAMODEM, 0);
if (lTapiReturn)
{
wsprintf (TempString,TEXT("%d"), lTapiReturn);
WideCharToMultiByte(CP_ACP, 0, TempString, -1, CharString, 20, NULL, NULL);
VTPrint("TAPI failed to Open Line\n\rError Code = ",0);
VTPrint(CharString, 0);
VTPrint("\n\r",0);
TAPIShutdown();
return FALSE;
}
//Request specific notification messages
lTapiReturn = lineSetStatusMessages(ghLine, LINEDEVSTATE_RINGING | LINEDEVSTATE_CONNECTED |
LINEDEVSTATE_DISCONNECTED | LINEDEVSTATE_OUTOFSERVICE |
LINEDEVSTATE_MAINTENANCE | LINEDEVSTATE_CLOSE |
LINEDEVSTATE_REINIT, LINEADDRESSSTATE_OTHER);
if (lTapiReturn)
{
wsprintf (TempString,TEXT("%d"), lTapiReturn);
WideCharToMultiByte(CP_ACP, 0, TempString, -1, CharString, 20, NULL, NULL);
VTPrint("TAPI failed to Set Status Messages\n\rError Code = ",0);
VTPrint(CharString, 0);
VTPrint("\n\r",0);
TAPIShutdown();
return FALSE;
}
//Configure line device for a data modem
memset(&LineCallParams, 0, sizeof(LineCallParams));
LineCallParams.dwTotalSize = sizeof(LineCallParams);
LineCallParams.dwBearerMode = LINEBEARERMODE_VOICE;
LineCallParams.dwMediaMode = LINEMEDIAMODE_DATAMODEM;
//Expect the line to start out idle (we don't want to break into a current call)
LineCallParams.dwCallParamFlags = LINECALLPARAMFLAGS_IDLE;
//If multiple addresses on the line, use the first address
LineCallParams.dwAddressMode = LINEADDRESSMODE_ADDRESSID;
LineCallParams.dwAddressID = 0;
}
//Make the call
if (ghCall == NULL)
{
#ifdef DEBUGVERSION
VTPrint("TAPI Making the call\r\n", 0);
#endif
lTapiReturn = lineMakeCall(ghLine, &ghCall, DialNumber, 0, &LineCallParams);
if (lTapiReturn < 0)
{
wsprintf (TempString,TEXT("%d"), lTapiReturn);
WideCharToMultiByte(CP_ACP, 0, TempString, -1, CharString, 20, NULL, NULL);
VTPrint("TAPI failed to Make the Call\n\rError Code = ",0);
VTPrint(CharString, 0);
VTPrint("\n\r",0);
TAPIShutdown();
ghCall = NULL;
return FALSE;
}
}
VTPrint("Call Initiated\r\n",0);
return TRUE;
}
if (wcscmp(lpszPortName, TEXT("RAS")) != 0)
{
{
// Open the serial port.
hPort = CreateFile (lpszPortName, // Pointer to the name of the port
GENERIC_READ | GENERIC_WRITE,
// Access (read-write) mode
0, // Share mode
NULL, // Pointer to the security attribute
OPEN_EXISTING,// How to open the serial port
0, // Port attributes
NULL); // Handle to port with attribute
// to copy
// If it fails to open the port, return FALSE.
if ( hPort == INVALID_HANDLE_VALUE )
{
// Could not open the port.
COMMPORTSHUT=TRUE;
MessageBox (hMainWnd, TEXT("Unable to open the port"),
TEXT("Error"), MB_OK);
dwError = GetLastError ();
return FALSE;
}
}
RetValue=InitiliseCommHandle();
return RetValue;
}
return TRUE;
}
//Initilise the communication handle, this occurs once a communication channel has been
//opened, either direct to a serial port or via TAPI
BOOL InitiliseCommHandle(void)
{
DWORD dwError,
dwThreadID;
DCB PortDCB;
COMMTIMEOUTS CommTimeouts;
#ifdef DEBUGVERSION
char SendString[40];
sprintf(SendString, "Handle = %d\r\n", hPort);
VTPrint(SendString,0);
#endif
// Get the default port setting information.
PortDCB.DCBlength = sizeof (DCB);
GetCommState (hPort, &PortDCB);
// Change the DCB structure settings.
if (wcscmp(COMMPORTNAME, TEXT("TAPI")) == 0)
{
//TAPI (modem) Settings
PortDCB.BaudRate = 19200; // Current baud
PortDCB.ByteSize = 8; // Number of bits/byte, 4-8
PortDCB.Parity = NOPARITY; // Parity odd,even,mark,space
}
else
{
//Standard Serial Port Settings
PortDCB.BaudRate = 1200; // Current baud
PortDCB.ByteSize = 7; // Number of bits/byte, 4-8
PortDCB.Parity = EVENPARITY; // Parity odd,even,mark,space
}
PortDCB.fBinary = TRUE; // Binary mode; no EOF check
PortDCB.fParity = TRUE; // Enable parity checking
PortDCB.fOutxCtsFlow = FALSE; // CTS output flow control
PortDCB.fRtsControl = RTS_CONTROL_HANDSHAKE;
PortDCB.fOutxDsrFlow = FALSE; // No DSR output flow control
PortDCB.fDtrControl = DTR_CONTROL_ENABLE; //DTR output ON
PortDCB.fDsrSensitivity = FALSE; // DSR sensitivity
PortDCB.fTXContinueOnXoff = TRUE; // XOFF continues Tx
PortDCB.fOutX = FALSE; // No XON/XOFF out flow control
PortDCB.fInX = FALSE; // No XON/XOFF in flow control
PortDCB.fErrorChar = FALSE; // Disable error replacement
PortDCB.fNull = FALSE; // Disable null stripping
PortDCB.fAbortOnError = FALSE; // Do not abort reads/writes on
// error
PortDCB.StopBits = ONESTOPBIT; // 0,1,2 = 1, 1.5, 2
// Configure the port according to the specifications of the DCB
// structure.
if (!SetCommState (hPort, &PortDCB))
{
MessageBox (hMainWnd, TEXT("Unable to configure the port"),
TEXT("Error"), MB_OK);
dwError = GetLastError ();
return FALSE;
}
// Retrieve the time-out parameters for all read and write operations
// on the port.
GetCommTimeouts (hPort, &CommTimeouts);
// Change the COMMTIMEOUTS structure settings.
CommTimeouts.ReadIntervalTimeout = MAXDWORD;
CommTimeouts.ReadTotalTimeoutMultiplier = 0;
CommTimeouts.ReadTotalTimeoutConstant = 0;
CommTimeouts.WriteTotalTimeoutMultiplier = 20;
CommTimeouts.WriteTotalTimeoutConstant = 1000;
// Set the time-out parameters for all read and write operations
// on the port.
if (!SetCommTimeouts (hPort, &CommTimeouts))
{
// Could set the timeouts.
MessageBox (hMainWnd, TEXT("Unable to set the port time-out parameters"),
TEXT("Error"), MB_OK);
dwError = GetLastError ();
return FALSE;
}
if (wcscmp(COMMPORTNAME, TEXT("TAPI")) != 0)
{
// Direct the port to perform extended functions SETDTR and SETRTS
// SETDTR: Sends the DTR (data-terminal-ready) signal.
// SETRTS: Sends the RTS (request-to-send) signal.
// EscapeCommFunction (hPort, SETDTR);
// EscapeCommFunction (hPort, SETRTS);
//Use the Swap Comms routine to set the serial port to the last open state
//This is a little messy to set the port first of all and then change some
//of the settings here
SwapComms(CurrentController);
}
// Create a read thread for reading data from the communication port.
if (hReadThread = CreateThread (NULL, 0, PortReadThread, 0, 0,
&dwThreadID))
{
CloseHandle (hReadThread);
}
else
{
// Could not create the read thread.
MessageBox (hMainWnd, TEXT("Unable to create the read thread"),
TEXT("Error"), MB_OK);
dwError = GetLastError ();
return FALSE;
}
return TRUE;
}
//TAPI sends status messages to this function.
void CALLBACK TapiCallBackFunction(DWORD dwdevice, DWORD dwMsg, DWORD dwCallbackInstance,
DWORD dwParam1, DWORD dwParam2, DWORD dwParam3)
{
DWORD lTapiReturn, dwStructSize;
VARSTRING *pvs, *pvsOld;
#ifdef DEBUGVERSION
char SendString[40];
#endif
pvs = NULL;
dwStructSize = sizeof (VARSTRING);
switch(dwMsg)
{
case LINE_CALLSTATE:
switch(dwParam1)
{
case LINECALLSTATE_IDLE:
if (hPort != INVALID_HANDLE_VALUE)
{
VTPrint("Line Idle\n\r",0);
//Change MENU back to COMM mode
ControllerMenu(TRUE);
//Shutdown TAPI
hPort = INVALID_HANDLE_VALUE;
lineDeallocateCall(ghCall);
ghCall = NULL;
ghLine = NULL;
}
break;
case LINECALLSTATE_CONNECTED:
//If a handle is already present then don't re-open
//This needs doing as multiple connected events can occur on connection
if (hPort != INVALID_HANDLE_VALUE)
break;
//Spin round loop till the structure is big enough
do
{ pvsOld = pvs;
if (NULL == (pvs = realloc (pvs, dwStructSize)))
break;
pvs->dwTotalSize = dwStructSize;
if (lTapiReturn = lineGetID (NULL, 0, ghCall, LINECALLSELECT_CALL,
pvs, TEXT("comm/datamodem")))
break;
}
while ((dwStructSize = pvs->dwNeededSize) > pvs->dwTotalSize) ;
if (pvs == NULL)
{
if (pvsOld)
free (pvsOld);
VTPrint("Failed to allocate port handle memory\n\r", 0);
TAPIShutdown();
break;
}
if (lTapiReturn)
{
free(pvs);
VTPrint("Failed to obtain port handle\n\r", 0);
TAPIShutdown();
break;
}
hPort = * (HANDLE*) ((char*) pvs + pvs->dwStringOffset);
free(pvs);
//Change Menu to Modem Mode
ControllerMenu(FALSE);
VTPrint("Connected\n\r", 0);
InitiliseCommHandle();
break;
case LINECALLSTATE_DIALING:
//VTPrint("Dialling\n\r", 0);
break;
case LINECALLSTATE_PROCEEDING:
//VTPrint("Waiting for an answer\n\r", 0);
break;
case LINECALLSTATE_DISCONNECTED:
ControllerMenu(TRUE);
//Change Menu to COMM mode
switch (dwParam2)
{
case LINEDISCONNECTMODE_UNREACHABLE:
VTPrint("Unreachable\r\n",0);
hPort = INVALID_HANDLE_VALUE;
break;
case LINEDISCONNECTMODE_BUSY:
VTPrint("Line Busy\n\r", 0);
break;
}
TAPIShutdown();
}
break;
default:
break;
}
}
[/code]
BOOL TAPIShutdown()
//Do the TAPI Shutdown Process
{
static bShuttingDown = FALSE;
//If we are not initilised then Shutdown unnecessary
if (ghLineApp == NULL)
return TRUE;
//Prevent Shutdown re-entrancy problems
if (bShuttingDown)
return TRUE;
bShuttingDown=TRUE;
if (ghCall != NULL)
lineDrop(ghCall, NULL, 0);
bShuttingDown = FALSE;
return TRUE;
}
Thanks for code posted. It is very helpful.
But I don't quite understand the logic how the "hPort" is created when receiveing a "CONNECTED" message callback.
Can you explain a little bit more?
- David
The handle to the port (hPort) is contained at the end of a variable length string (VARSTRING) that is returned from the call to LineGetID.
The fiddly thing about it is you give LineGetID a pointer to a VARSTRING called pvs and you have to fill in one of the member variables of pvs with the size allocated ( pvs->dwTotalSize ) to the variable length string.
Since I don't know how much to allocate to the VARSTRING, initially I just allocate enough memory from a sizeof(VARSTRING) result. Maybe you could just allocate a set size and not bother with the looping back, I think it is better to ask the system how much memory it wants as LineGetID may need more memory in later versions of the operating system.
Then you pass the VARSTRING with it's size stored in dwTotalSize to the function LineGetID.
The LineGetID function then fills in dwNeededSize with the size of the VARSTRING it needed to complete. That is why I loop back and re-allocate the VARSTRING to a new (bigger) size if NeededSize is greater than TotalSize.
Once the LineGetID function succeeds with a big enough VARSTRING then the Port Handle is at the end of the VARSTRING, as it is a variable length string you have to do maths to say the Port Handle is at the Address of the string PLUS the offset to the actural data wanted i.e. pvs + pvs->dwStringOffset The maths must be done with char* byte sizes and the final result is a handle, hence the casting HANDLE* on the final result.
Once the Port Handle is stored in hPort, the memory allocated to pvs is freed.
One other thing I noticed is that you can get multiple CONNECTED events, that is why I just exit the CONNECTED event if there is already a valid handle
I hope that makes sense.
Cheers
Paul
Do you have sample for the answering part?
thanks,
- David
No, sorry I have only ever written programs to dial out.
Hi,
I tried the sample code posted in this thread. It works only if I used
LineCallParams.dwBearerMode = LINEBEARERMODE_VOICE;
LineCallParams.dwMediaMode = LINEMEDIAMODE_INTERACTIVEVOICE;
combination. I got the RING message. However, the original:
LineCallParams.dwBearerMode = LINEBEARERMODE_VOICE;
LineCallParams.dwMediaMode = LINEMEDIAMODE_DATAMODEM;
didn't seem to work.
Do I miss something? (I think I have successfully killed the cprog.exe already)
Thanks,
- David
That means you are making a voice call.
So is the problem that you can not make a data(modem) type call ?
Check that you have data enabled on your SIM and also that under Settings -> Connections -> CSD Line Type it is set correctly. In the UK it is 9600 bps(v.32) and Non-tranparent, but I was told it is v110 is the states.
Let me know how you get on.
Is there any chance that somebody could compile this TAPI code as an object I could consume in C#? I have tried, but I am not even able to compile the example in C++... it's just not my world!
I would be eternally gratefull - and I bet a whole bunch of other guys who just want to quickly establish a data connection over GSM from C# (or VB?) would be also! It should have been in the phone.dll if you ask me!
compiled sample
Hey could somebody compile the tapi code for me in eVc++ or MFC ?? because i am really struggling. Plus what is toolbox.h i dont seem to have it ?? can somebody please help ??
thanks guys
This is an old post of mine, don't worry about Toolbox.h that was for the program I was writing and it has nothing to do with Tapi.
This sample code was not meant to compile, after you you won't have function VTPrint but I hope you can guess that just shows text. It was just posted to demonstate the order of functions needed to get a modem connection.
I built all this Tapi code into a DLL and I have it all presented with the eVC 3.0 build files in this post, this code will compile as presented and is just a zip of all the project files of a single sample application.
http://forum.xda-developers.com/viewtopic.php?t=18978
Have a look there.
Cheers
Paul
during a data call when using TAPI can u make some kind of AT command request ??? and retrieve the data from that answer ??? And do i need some TAPI app on the remote unit to send the data back ?
i am trying to access a remote unit ( GPS RX and GSM TX )
I don't really understand your question that well.
But AT commands have nothing to do with TAPI, so any question saying can TAPI send an AT command for etc -- The answer must be no.
All TAPI does is gives a Handle that can be used with ReadFile and WriteFile for receiving and sending data over the modem.
So TAPI will dial a number and establish a DataModem connection, then on Connect it can provide the handle for you to direct read/write requests to. Once the link is established you just treat the handle as if it was a file handle returned from a CreateFile command.
As said earlier all this has nothing to do with AT commands.
During a data call should ic onnect via COM 1 or COM 9 if i'm using TAPI ?? Would you have any sample code i could have a look at ? I'm a bit lost at the moment .... with LineGetID too ...
you can't use COM2 or COM9 via TAPI cause COM2 and COM9 masked by RIL
about lineGetID look http://forum.xda-developers.com/viewtopic.php?t=9761
ok thanks - so if i cant use COM1 or COM9 in this case then i'm guessing that i shall pass a string (lpszPortName) just like the example on this post.
Code:
// Open the serial port.
hPort = CreateFile (lpszPortName, // Pointer to the name of the port
GENERIC_READ | GENERIC_WRITE,
// Access (read-write) mode
0, // Share mode
NULL, // Pointer to the security attribute
OPEN_EXISTING,// How to open the serial port
0, // Port attributes
NULL); // Handle to port with attribute
// to copy
But what should the string lpszPortName be initialized to ? Or am i totally wrong ?[/quote]
L"COM9:" for COM9
but not with TAPI
with TAPI you have not open any COM-ports
you must use lineGetID
Code:
//PART 7 - TIMEOUT AND DCB SETTINGS
PortDCB.BaudRate = 115200;
PortDCB.fBinary = TRUE;
PortDCB.fParity = FALSE;
PortDCB.fOutxCtsFlow = FALSE;
PortDCB.fOutxDsrFlow = FALSE;
PortDCB.fDtrControl = DTR_CONTROL_ENABLE;
PortDCB.fDsrSensitivity = FALSE;
PortDCB.fTXContinueOnXoff = FALSE;
PortDCB.fOutX = FALSE;
PortDCB.fInX = FALSE;
PortDCB.fErrorChar = FALSE;
PortDCB.fNull = FALSE;
PortDCB.fRtsControl = RTS_CONTROL_DISABLE;
PortDCB.fAbortOnError = FALSE;
PortDCB.ByteSize = 8;
PortDCB.Parity = NOPARITY;
PortDCB.StopBits = ONESTOPBIT;
if (!SetCommState (hPort, &PortDCB))
{
MessageBox (_T("unable to configure com port "));
return FALSE;
}
GetCommTimeouts (hPort, &CommTimeouts);
CommTimeouts.ReadIntervalTimeout = MAXDWORD;
CommTimeouts.ReadTotalTimeoutMultiplier = 0;
CommTimeouts.ReadTotalTimeoutConstant = 0;
CommTimeouts.WriteTotalTimeoutMultiplier = 20;
CommTimeouts.WriteTotalTimeoutConstant = 1000;
if (!SetCommTimeouts (hPort, &CommTimeouts))
{
MessageBox (_T("unable to set comport parameters"));
return FALSE;
}
Are the COM and Timeout settings necessary when using TAPI ? because i am getting an error message at the !setCommState function.
I use lineGetID to retrieve the Handle to the Comm then i try to use readFile but the operation is unsuccesful.
Anyhelp from out there ? thanks.
Are you sure that you call lineGetID only after connection?
Maybe you are right. I just do lineMakeCall then do lineGetId without waiting for a LINECALLSTATE_CONNECTED message.
I think its because i have troubles implementing the lineCallBackFunc() i dont understand the parameters that need to be passed to it.
Code:
void CALLBACK lineCallbackFunc(
DWORD dwDevice, DWORD dwMsg, DWORD dwCallbackInstance,
DWORD dwParam1, DWORD dwParam2, DWORD dwParam3)
{
Anyhelp for this ?? Cheers.
I love Android. I want to learn to develop apps. I keep reading tutorials. I got dissapointed and read about HTML frameworks (phonegap, etc). I came back to Android Native Java. I want to learn from the roots. However, some things discourages me....
All this part of the code is just for making a request to the Openweather API and get the json data (plus a little debugging stuff); which in Python or similar languages you only have to care about
- importing the library that handles http requests
- make the request in one function and save it into a json object
Code:
HttpURLConnection urlConnection = null;
BufferedReader reader = null;
// Will contain the raw JSON response as a string.
String forecastJsonStr = null;
String format = "json";
String units = "metric";
int numDays = 7;
try {
final String FORECAST_BASE_URL =
"<the-domain>/data/2.5/forecast/daily?";
final String QUERY_PARAM = "q";
final String FORMAT_PARAM = "mode";
final String UNITS_PARAM = "units";
final String DAYS_PARAM = "cnt";
Uri builtUri = Uri.parse(FORECAST_BASE_URL).buildUpon()
.appendQueryParameter(QUERY_PARAM, params[0])
.appendQueryParameter(FORMAT_PARAM, format)
.appendQueryParameter(UNITS_PARAM, units)
.appendQueryParameter(DAYS_PARAM, Integer.toString(numDays))
.build();
URL url = new URL(builtUri.toString());
Log.v(LOG_TAG, "Built URI " + builtUri.toString());
// Create the request to OpenWeatherMap, and open the connection
urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.setRequestMethod("GET");
urlConnection.connect();
// Read the input stream into a String
InputStream inputStream = urlConnection.getInputStream();
StringBuffer buffer = new StringBuffer();
if (inputStream == null) {
// Nothing to do.
return null;
}
reader = new BufferedReader(new InputStreamReader(inputStream));
String line;
while ((line = reader.readLine()) != null) {
buffer.append(line + "\n");
}
if (buffer.length() == 0) {
// Stream was empty. No point in parsing.
return null;
}
forecastJsonStr = buffer.toString();
Log.v(LOG_TAG, "Forecast string: " + forecastJsonStr);
} catch (IOException e) {
Log.e(LOG_TAG, "Error ", e);
// If the code didn't successfully get the weather data, there's no point in attemping
// to parse it.
return null;
} finally {
if (urlConnection != null) {
urlConnection.disconnect();
}
if (reader != null) {
try {
reader.close();
} catch (final IOException e) {
Log.e(LOG_TAG, "Error closing stream", e);
}
}
}
This is the complete Class:
Code:
public class FetchWeatherTask extends AsyncTask<String, Void, String[]> {
private final String LOG_TAG = FetchWeatherTask.class.getSimpleName();
/* The date/time conversion code is going to be moved outside the asynctask later,
* so for convenience we're breaking it out into its own method now.
*/
private String getReadableDateString(long time){
// Because the API returns a unix timestamp (measured in seconds),
// it must be converted to milliseconds in order to be converted to valid date.
Date date = new Date(time * 1000);
SimpleDateFormat format = new SimpleDateFormat("E, MMM d");
return format.format(date).toString();
}
/**
* Prepare the weather high/lows for presentation.
*/
private String formatHighLows(double high, double low) {
// For presentation, assume the user doesn't care about tenths of a degree.
long roundedHigh = Math.round(high);
long roundedLow = Math.round(low);
String highLowStr = roundedHigh + "/" + roundedLow;
return highLowStr;
}
/**
* Take the String representing the complete forecast in JSON Format and
* pull out the data we need to construct the Strings needed for the wireframes.
*
* Fortunately parsing is easy: constructor takes the JSON string and converts it
* into an Object hierarchy for us.
*/
private String[] getWeatherDataFromJson(String forecastJsonStr, int numDays)
throws JSONException {
// These are the names of the JSON objects that need to be extracted.
final String OWM_LIST = "list";
final String OWM_WEATHER = "weather";
final String OWM_TEMPERATURE = "temp";
final String OWM_MAX = "max";
final String OWM_MIN = "min";
final String OWM_DATETIME = "dt";
final String OWM_DESCRIPTION = "main";
JSONObject forecastJson = new JSONObject(forecastJsonStr);
JSONArray weatherArray = forecastJson.getJSONArray(OWM_LIST);
String[] resultStrs = new String[numDays];
for(int i = 0; i < weatherArray.length(); i++) {
// For now, using the format "Day, description, hi/low"
String day;
String description;
String highAndLow;
// Get the JSON object representing the day
JSONObject dayForecast = weatherArray.getJSONObject(i);
// The date/time is returned as a long. We need to convert that
// into something human-readable, since most people won't read "1400356800" as
// "this saturday".
long dateTime = dayForecast.getLong(OWM_DATETIME);
day = getReadableDateString(dateTime);
// description is in a child array called "weather", which is 1 element long.
JSONObject weatherObject = dayForecast.getJSONArray(OWM_WEATHER).getJSONObject(0);
description = weatherObject.getString(OWM_DESCRIPTION);
// Temperatures are in a child object called "temp". Try not to name variables
// "temp" when working with temperature. It confuses everybody.
JSONObject temperatureObject = dayForecast.getJSONObject(OWM_TEMPERATURE);
double high = temperatureObject.getDouble(OWM_MAX);
double low = temperatureObject.getDouble(OWM_MIN);
highAndLow = formatHighLows(high, low);
resultStrs[i] = day + " - " + description + " - " + highAndLow;
}
for (String s : resultStrs) {
Log.v(LOG_TAG, "Forecast entry: " + s);
}
return resultStrs;
}
@Override
protected String[] doInBackground(String... params) {
// If there's no zip code, there's nothing to look up. Verify size of params.
if (params.length == 0) {
return null;
}
// These two need to be declared outside the try/catch
// so that they can be closed in the finally block.
HttpURLConnection urlConnection = null;
BufferedReader reader = null;
// Will contain the raw JSON response as a string.
String forecastJsonStr = null;
String format = "json";
String units = "metric";
int numDays = 7;
try {
// Construct the URL for the OpenWeatherMap query
// Possible parameters are avaiable at OWM's forecast API page
final String FORECAST_BASE_URL =
"<the-domain>/data/2.5/forecast/daily?";
final String QUERY_PARAM = "q";
final String FORMAT_PARAM = "mode";
final String UNITS_PARAM = "units";
final String DAYS_PARAM = "cnt";
Uri builtUri = Uri.parse(FORECAST_BASE_URL).buildUpon()
.appendQueryParameter(QUERY_PARAM, params[0])
.appendQueryParameter(FORMAT_PARAM, format)
.appendQueryParameter(UNITS_PARAM, units)
.appendQueryParameter(DAYS_PARAM, Integer.toString(numDays))
.build();
URL url = new URL(builtUri.toString());
Log.v(LOG_TAG, "Built URI " + builtUri.toString());
// Create the request to OpenWeatherMap, and open the connection
urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.setRequestMethod("GET");
urlConnection.connect();
// Read the input stream into a String
InputStream inputStream = urlConnection.getInputStream();
StringBuffer buffer = new StringBuffer();
if (inputStream == null) {
// Nothing to do.
return null;
}
reader = new BufferedReader(new InputStreamReader(inputStream));
String line;
while ((line = reader.readLine()) != null) {
// Since it's JSON, adding a newline isn't necessary (it won't affect parsing)
// But it does make debugging a *lot* easier if you print out the completed
// buffer for debugging.
buffer.append(line + "\n");
}
if (buffer.length() == 0) {
// Stream was empty. No point in parsing.
return null;
}
forecastJsonStr = buffer.toString();
Log.v(LOG_TAG, "Forecast string: " + forecastJsonStr);
} catch (IOException e) {
Log.e(LOG_TAG, "Error ", e);
// If the code didn't successfully get the weather data, there's no point in attemping
// to parse it.
return null;
} finally {
if (urlConnection != null) {
urlConnection.disconnect();
}
if (reader != null) {
try {
reader.close();
} catch (final IOException e) {
Log.e(LOG_TAG, "Error closing stream", e);
}
}
}
try {
return getWeatherDataFromJson(forecastJsonStr, numDays);
} catch (JSONException e) {
Log.e(LOG_TAG, e.getMessage(), e);
e.printStackTrace();
}
// This will only happen if there was an error getting or parsing the forecast.
return null;
}
}
I mean, I know this code can be reduced, but I'm angry about the way it works. Everything needs to be passed to another object! And even rembember all those castings! Castings everywhere!
- The builded URI to the URL.
- The URL to the HttpConection variable.
- Once you connect, save that into the InputStream.
- Make a StringBuffer because we are going to send line by line everything.
- Then create the reader = new BufferedReader(new InputStreamReader(inputStream)).
- Append the lines to the buffer and return if it's ok.
- Else catch all the errors and be sure to close all the connections.
Damn Java !
Forgive me. You'll hate me.
Java is readable, that's the truth... but don't tell me that it is easy for a normal person.
Am I the only one?
If you are a beginner and will straight move to these classes. You will obviously find Java difficult. But Java is very easy if you move step by step from start
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---------- Post added at 04:18 PM ---------- Previous post was at 04:16 PM ----------
And that library also does the same thing inside. Only difference is, your work is already done by author of the library.
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Java is definitely a very verbose language but it's also widely used and so you will find many libraries that do tasks like grab JSON data from a service that have already been implemented for you
manwoman said:
Damn Java !
Forgive me. You'll hate me.
Java is readable, that's the truth... but don't tell me that it is easy for a normal person.
Am I the only one?
Click to expand...
Click to collapse
I don't think you're the only one. It's easy to get scared away by the many too verbose examples available, the key is to look at what you're trying to achieve and then break it up into those parts.
Your code listing is (I think) an attempt to show all steps to get the forecast data, but if that would have been broken up into smaller steps I don't think you'd look at it as quite as bad.
You would then have methods like
Code:
URL getForecastUrl(String parameter);
Code:
BufferedReader getUrl(URL url) { }
Code:
String readAll(BufferedReader reader) {}
Each of which would have had something like 6-7 lines of simple, cohesive code.
I understand your point, but in this particular scenario I think you're the victim of a poorly structured code sample rather than a too verbose language.
If you think the default implementation is too complicated, here are also many java libraries which will make your life easier.