This function constructs an ENVIStartMessage object to send to the ENVIBroadcastChannel. If the ENVI user interface is running, then a progress dialog will appear.
Example
This example demonstrates how all of the ENVI API messaging components work together. It simulates an analytic operation and updates its progress in a progress bar and in the IDL console.
PRO ProgressBarAbortExample
COMPILE_OPT idl2
e = ENVI()
Channel = e.GetBroadcastChannel()
Abort = ENVIAbortable()
Start = ENVIStartMessage('Progress Bar Title', Abort)
Channel.Broadcast, Start
nSteps = 73
Progress = ENVIProgressMessage('Executing Progress Message', $
0, Abort)
FOR stepIndex=0, nSteps DO BEGIN
percentProgress = Round(stepIndex* 100.0/nSteps)
Progress.Percent = percentProgress
Channel.Broadcast, Progress
IF (Abort.Abort_Requested) THEN BREAK
dataProcess = dist(1000)
PRINT, stepIndex
ENDFOR
Finish = ENVIFinishMessage(Abort)
Channel.Broadcast, Finish
END
Syntax
Result = ENVIStartMessage(Message, SourceObject)
Return Value
This function returns a reference to an ENVIStartMessage object.
Arguments
Message
Specify a string indicating the title of the progress dialog.
SourceObject
Specify an object to have the message uniquely identified. If you provide an object that implements the ENVIAbortable interface, then the progress dialog will have a Cancel button and you can query the ABORT_REQUESTED property on your object to determine if the user cancelled the progress dialog.
Keywords
ERROR (optional)
Set this keyword to a named variable that will contain any error message issued during execution of this routine. If no error occurs, the ERROR variable will be set to a null string (''). If an error occurs and the routine is a function, then the function result will be undefined.
When this keyword is not set and an error occurs, ENVI returns to the caller and execution halts. In this case, the error message is contained within !ERROR_STATE and can be caught using IDL's CATCH routine. See IDL Help for more information on !ERROR_STATE and CATCH.
See Manage Errors for more information on error handling in ENVI programming.
Version History
API Version
4.3
See Also
ENVIBroadcastChannel, ENVIProgressMessage, ENVIFinishMessage, Messaging