[Gambas-user] App idle with long loops

[Demosthenes Koptsis]

On 8/10/2016 19:09 μμ, Tobias Boege wrote:
> On Sat, 08 Oct 2016, Demosthenes Koptsis wrote:
>> Hello,
>>
>> i have very long (time consuming) For loops and my app is frozen until
>> loop is finished.
>>
>> for example i wget urls with a custom Sub which Shell("wgetURLS.sh") To
>> sOUTPUT
>>
>>     'get urls
>>     For i = 0 To iDepth
>>       wgetURLS(i * 10)
>>     Next
>>
>> Public Sub wgetURLS(iStart As Integer)
>> .....
>>
>> Shell("wgetURLS.sh") To sOUTPUT
>>
>> .....
>>
>> --------------
>>
>> Is there possible to set the gui idle and the same time run For...loops?
>>
> If you only want to refresh the GUI (e.g. if your For loops update a
> ProgressBar on your form and you want to update the value of that bar
> during the loop), then Wait [1] is sufficient.
>
> If you want the GUI to be fully operatable while your loops run in the
> background, you have to use a background Task [2]. As Gambas is single-
> threaded, Tasks are implemented as external processes which execute one
> of your classes. This limits the things you can do with Tasks (you cannot
> directly modify the main program, for example, but have to send data and
> status reports through a pipe from your Task to the main process and
> interpret them there). However, if all you want is loading some files via
> wget, that should not be a problem.
>
> Of course, there is also the gb.net.curl component which can download files
> asynchronously. If you can use that (which depends on what you want to do),
> you should.
>
> And as a fourth option, looking further into your code: if you want to
> execute shell scripts in a For loop, then don't use the Shell-To syntax
> but create a Process object instead and accumulate its output in Read
> events. The event loop will take care of everything and the GUI will be
> usable without any extra effort on your side.
>
> Finding the best solution depends, who would have thought, on what you want
> to do *specifically*. Tasks are the most general and most cumbersome option.
>
> Regards,
> Tobi
>
> [1] http://gambaswiki.org/wiki/lang/wait
> [2] http://gambaswiki.org/wiki/comp/gb/task
>
Thanks very much for the details.

Regards,

Dim