[Qgis-developer] qgis crash using QThread in a plugin script

[Sergio Vignali]

Hi Akbar,

as you suggested I removed return but it didn't solve the problem...
I don't get it because when I open the dialog the first time I can play
with it changing word without problem
(I mean that I can insert a new word several time and when I push apply
everything works well).
I think it's something that I should destroy when closing the dialog... but
I don't find what!
Two strange behaviours that I found is that sometimes after restarting the
dialog if I insert the same word I inserted during the
last run the plugin works well or if I change word it writes double items,
like digiting "et" it inserts "ee" and "tt" and after it crashes, but how
it gets
the double letters in the loop?...
It's for sure something related to the restarting as if I use the plugin
reload it doesn't crash...
Any idea? Anyway thanks for your suggestion!

All the best
s.

2016-09-10 10:42 GMT+02:00 Sergio Vignali <vignalisergio30 at gmail.com>:

> Hi Akbar,
> thank you for your answer, I'm abroad till Tuesday but I will test it asap
> and let you know.
> Best
>
> Il 09/set/2016 05:04, "Akbar Gumbira" <akbargumbira at gmail.com> ha scritto:
>
>> Hi Sergio,
>>
>> DId you fix already your problems? I am not sure if my answer is 100%
>> correct (so I don't post it in stackexchange) as  I didnt try it, but by
>> judging your code:
>>
>> If I click apply without entering anything in the QLineEdit the
>>> QgsMessageBar appears correctly but if I close the QDialog and I do the
>>> same the QgisMessageBar has two items (1 more, see picture)
>>
>>
>> Plugins initiallization happened when starting QGIS. So the plugin is
>> already instantiated (along with your dialog, message bar, etc). Restarting
>> (that is closing and opening again) the dialog in your code doesn't destroy
>> all the instances. That is why the message bar has the previous messages.
>> You can just clear the message bar once user opens the dialog.
>>
>> If I insert a word in the QLineEdit after opening the plugin for the
>>> second time, clicking on apply Qgis crashes.
>>
>>
>> This is not necessarily related to the crash :p:
>>
>>    -
>>
>>    word = unicode(self.dlg.inputedit.text())
>>
>>
>> But QString is stored in unicode, no need to recast it
>>
>> For the cause of the crash, I strongly believe this is the problem:
>>
>>     def add_item(self, item):
>>         self.list.addItem(item)
>>         return
>>
>> Can you try to remove return there? I think it's forcing the thread to go
>> back to the main loop (plugin Run method)
>>
>> Cheers
>>
>>
>>
>> On Wed, Sep 7, 2016 at 1:57 PM, Sergio Vignali <vignalisergio30 at gmail.com
>> > wrote:
>>
>>> I posted my problem in gis.stackexchange, (http://gis.stackexchange.com/
>>> questions/209602/qgis-crash-using-qthread-in-a-plugin-script).
>>> There you can find the full explanation of the problem and all the code
>>> I used... It would be great to get some feedbacks!
>>> Best
>>> s.
>>>
>>> 2016-09-06 3:58 GMT+02:00 Akbar Gumbira <akbargumbira at gmail.com>:
>>>
>>>> It would be more helpful if you point to the code here. I had a problem
>>>> with QThread (was initially inheriting QThread) but managed to fix the
>>>> problem by creating workers and move the worker object to thread. This is a
>>>> good article about multithreading in qgis
>>>> https://snorfalorpagus.net/blog/2013/12/07/multithreading-in
>>>> -qgis-python-plugins/
>>>>
>>>> On Sep 5, 2016 23:01, "Sergio Vignali" <vignalisergio30 at gmail.com>
>>>> wrote:
>>>>
>>>>> Dear all,
>>>>>
>>>>> I wrote a python script that aims to execute neighbourhood statistics
>>>>> in raster layer. My script uses QThread to update a QList and a
>>>>> QProgressBar and everithing works fine if I run the script from PyCharm,
>>>>> the progressbar and the list are updated. The problem appears when I move
>>>>> my script in a Qgis plugin, the UI appears correctly but clicking OK the
>>>>> software crashes...
>>>>> I am using qgis 2.14 in a linux machine, do you have any advice?
>>>>>
>>>>> All the best
>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> Sergio Vignali
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> Qgis-developer mailing list
>>>>> Qgis-developer at lists.osgeo.org
>>>>> List info: http://lists.osgeo.org/mailman/listinfo/qgis-developer
>>>>> Unsubscribe: http://lists.osgeo.org/mailman/listinfo/qgis-developer
>>>>>
>>>>
>>>
>>>
>>> --
>>> Sergio Vignali
>>>
>>>
>>
>>
>> --
>>
>> *-------------------*
>> *Akbar Gumbira *
>> *www.akbargumbira.com <http://www.akbargumbira.com>*
>>
>


-- 
Sergio Vignali
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