[QGIS-Developer] How to transfer data between QGIS Python plugins?

[Nyall Dawson]

On Fri, 23 Apr 2021 at 13:08, Etienne Trimaille
<etienne.trimaille at gmail.com> wrote:
>
> Not recommended because others already gave the qgis.utils.plugins dictionary, but you can do "from plugin_a.xxxx import yyy" from you plugin B.

Actually I would recommend avoiding both the qgis.utils.plugins
dictionary AND the from plugin.*** approach, UNLESS you maintain both
plugins. Plugin API isn't guaranteed to be stable, and if your plugin
relies on someone else's plugin to work then there's the risk that
they'll refactor and change their plugin and break yours in turn.

So unless you know that this won't happen, I would strongly suggest
going via the processing route only.

Nyall


>
> Le ven. 23 avr. 2021 à 04:43, Tobias Schmetzer <tschmetzer at gmx.de> a écrit :
>>
>> Hello Zac,
>>
>> I just saw you were helped and I'm happy the functionality solved your problem!
>>
>> If you feel there's a lack of documentation and you've got an idea how to improve it I think the best thing to do is to support this documentation with a contribution. This is how I started when I realised something was missing and I suggested to add this or that bit of information.
>>
>> It's easy to sign up on GitHub and make a suggestion. You can't damage anything. Everything will get reviewed and maybe discussed. There's also guidelines in the docs how to contribute.
>>
>> Best regards, Tobias
>>
>> 22.04.2021 14:09:30 Zac Wang <zacwang15 at gmail.com>:
>>
>> Hi guys,
>>
>> Thank you for all your replies.
>>
>> 'qgis.utils.plugins' really resolves my problem.
>>
>> This issue obsessed me for a few days, and your advice is fantastic.
>>
>> I can't understand why there is no documentation for such a useful functionality.
>>
>> Anyway, thank you for your help. Appreciate it.
>>
>>
>> Cheers,
>>
>> Zac
>>
>>
>> On Thu, 22 Apr 2021 at 22:01, Raymond Nijssen <r.nijssen at terglobo.nl> wrote:
>>>
>>> Hi Zac,
>>>
>>> You can use:
>>>
>>> qgis.utils.plugins
>>>
>>> to get a dictionary with all active plugins.
>>>
>>>
>>>
>>> To find out if another plugin is available:
>>>
>>> 'processing' in qgis.utils.plugins
>>>
>>>
>>>
>>> And use it like:
>>>
>>> processing_pl = qgis.utils.plugins['processing']
>>> processing_pl.toolbox.searchBox.setText('overlay')
>>>
>>>
>>> Hope this helps,
>>>
>>> Raymond
>>>
>>>
>>> On 22-04-2021 13:07, Zac Wang wrote:
>>> > Hi all,
>>> >
>>> > Are there some ways to transfer data between different pyqgis plugins? I
>>> > hope plugins share state.
>>> >
>>> > The only way I found is to make pluginA to be a child component of
>>> > QgisApp(iface.mainWindow()).
>>> >
>>> > Then in another pluginB, call findChild() to get the object(pluginA) and
>>> > connect its signal.
>>> >
>>> > This is a possible solution, but it's not easy to maintain because
>>> > plugins are not initiated in the same file.
>>> >
>>> > Is there a better solution?
>>> >
>>> > Regards,
>>> >
>>> > Zac
>>> >
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