GPSGetPosition (Function)

Retrieves information about the current device position.

Versions 16 and later

This function is now available in Browser code.

New in version 16

This function is now available in Browser code.

Versions 22 and later

This function is now available for the WINDEV applications.

New in version 22

This function is now available for the WINDEV applications.

Example

MyPosition is geoPosition
MyPosition = GPSGetPosition()
// Checks the position validity with ErrorOccurred
IF ErrorOccurred THEN RETURN
Info(" Latitude : " + MyPosition..Latitude)
Info(" Longitude : " + MyPosition..Longitude)

Versions 16 and later

// Geolocation from WEBDEV, a browser procedure is called.
// Process performed from a button whose action is "none"
GPSGetPosition(BrowserProc, 200)

// "BrowserProc" browser procedure
PROCEDURE BrowserProc(MyPosition is geoPosition, nMyError is int)

SWITCH nMyError

CASE gpsErrorOK
// No error was detected
PAGE_Page1.EDT_NoName1 = MyPosition..Altitude + " " + ...
MyPosition..Longitude
CASE gpsErrorRights
PAGE_Page1.EDT_NoName1 = ...
"The browser has no sufficient rights " + ...
"to use the geolocation (or non-HTTPS site)."
CASE gpsErrorPosition
PAGE_Page1.EDT_NoName1 = "Unable to define the position " + ...
"(internal error of provider for example)."
CASE gpsErrorTimeout
PAGE_Page1.EDT_NoName1 = ...
"The position was not retrieved " + ...
" within the alloted time."
OTHER CASE
PAGE_Page1.EDT_NoName1 = "Undefined error"
END

New in version 16

// Geolocation from WEBDEV, a browser procedure is called.
// Process performed from a button whose action is "none"
GPSGetPosition(BrowserProc, 200)

// "BrowserProc" browser procedure
PROCEDURE BrowserProc(MyPosition is geoPosition, nMyError is int)

SWITCH nMyError

CASE gpsErrorOK
// No error was detected
PAGE_Page1.EDT_NoName1 = MyPosition..Altitude + " " + ...
MyPosition..Longitude
CASE gpsErrorRights
PAGE_Page1.EDT_NoName1 = ...
"The browser has no sufficient rights " + ...
"to use the geolocation (or non-HTTPS site)."
CASE gpsErrorPosition
PAGE_Page1.EDT_NoName1 = "Unable to define the position " + ...
"(internal error of provider for example)."
CASE gpsErrorTimeout
PAGE_Page1.EDT_NoName1 = ...
"The position was not retrieved " + ...
" within the alloted time."
OTHER CASE
PAGE_Page1.EDT_NoName1 = "Undefined error"
END

// Geolocation from WEBDEV, a browser procedure is called.
// Process performed from a button whose action is "none"
GPSGetPosition(BrowserProc, 200)

// "BrowserProc" browser procedure
PROCEDURE BrowserProc(MyPosition is geoPosition, nMyError is int)

SWITCH nMyError

CASE gpsErrorOK
// No error was detected
PAGE_Page1.EDT_NoName1 = MyPosition..Altitude + " " + ...
MyPosition..Longitude
CASE gpsErrorRights
PAGE_Page1.EDT_NoName1 = ...
"The browser has no sufficient rights " + ...
"to use the geolocation (or non-HTTPS site)."
CASE gpsErrorPosition
PAGE_Page1.EDT_NoName1 = "Unable to define the position " + ...
"(internal error of provider for example)."
CASE gpsErrorTimeout
PAGE_Page1.EDT_NoName1 = ...
"The position was not retrieved " + ...
" within the alloted time."
OTHER CASE
PAGE_Page1.EDT_NoName1 = "Undefined error"
END

Syntax

Retrieving the information in browser code Hide the details

GPSGetPosition([<Procedure name> [, <Timeout>]])

<Procedure name>: Character string (with or without quotes)

Name of WLanguage procedure in browser code ("callback") called when the position is retrieved.
This procedure has the following format:

PROCEDURE <Procedure name>(<Position>,<Error>)

where:
<Position> is a geoPosition variable containing the information about the position. To find out whether the ..Speed, ..Precision, ..Direction or ..Altitude properties of geoPosition variable have been filled when retrieving the position, use ..SpeedValid, ..PrecisionValid, ..DirectionValid and ..AltitudeValid.
<Error> is an Integer constant corresponding to the error code and that can take the following values:
gpsErrorOK No error was detected.
gpsErrorRights
The browser has no sufficient rights to use geolocation.
The browser is recent and the site is not using the HTTPS secure protocol.
gpsErrorPosition Unable to define the position (internal error of provider for example).
gpsErrorTimeout The position could not be retrieved within the timeout.

<Timeout>: Optional integer or optional Duration

Maximum timeout (in hundredths of a second) for updating the device position.
If this timeout ends before the device position is updated, gpsErrorTimeOut is returned in the <Error> parameter of the WLanguage procedure.
If this parameter is not specified, the timeout is set to 1 minute.
Remark: This parameter can correspond to:
an integer corresponding to the number of hundredths of a second,
a Duration variable,
Versions 23 and later
the direct indication of duration (1 s or 10 ms for example).
New in version 23
the direct indication of duration (1 s or 10 ms for example).
the direct indication of duration (1 s or 10 ms for example).

Remarks

Managing locks

GPSGetPosition is a locking function until the current device position was retrieved or until the timeout defined by the <Timeout> parameter has expired.

If the function is called in the main thread of the application, an hourglass will be displayed during the function execution. The message displayed by the hourglass can be specified via the <Message> parameter.
Otherwise, the execution of secondary thread will be locked during the function execution and no hourglass will be displayed.

This function is not locking.

Remark: To find out the last known device position without timeout, use GPSLastPosition. Caution, the positioning information that was retrieved may not correspond to the current device position if the device was moved while the GPS signal was not valid for example. To find out the date and time at which the position was calculated, use the ..MeasurementDate property of the geoPosition variable.

Browsers allowing the geolocation

Caution: The geo-localization is available for the most recent browsers only:

FireFox from version 3.5,
Chrome from version 5.0.342.1,
Opera from version 10.6,
Safari from version 5.0.

During the call to a geo-localization function, the browser requests the authorization to localize.

Remark: From Chrome 50 (including on Android), GPSGetPosition can only be used on the sites secured via an SSL certificate for example. If the site is not secured, the function returns a result that cannot be used. During the test in local (localhost), the function operates properly.

Business / UI classification : Business Logic

Component : wd250java.dll