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Hi Tom,<br>
<br>
Hmm... Maybe there is such a method do determine the context (can't
recall right now). But in your case I would simply use something
like:<br>
<br>
geom = ...<br>
parishField = ...<br>
if not geom:<br>
parishField.setPlaceholderText('No geometry found')<br>
return<br>
<br>
<div class="moz-cite-prefix">On 05/03/2016 04:49 PM, Thomas Colley
wrote:<br>
</div>
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<div class="WordSection1">
<p class="MsoNormal"><span style="color:#1F497D">Hi Matthias<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Thanks for the
explanation, I think I am using globals where I shouldn’t
be. In this case I don’t think it’s the global variable
causing the problem though.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">I’ve stripped
everything back to a really simple example (no global
variables). I have a custom UI with one QLineEdit called
parish.
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">On opening the
form Python performs an intersect with the feature against a
polygon layer of parishes and uses the parish name to set
the text in the QLineEdit.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">from
PyQt4.QtCore import *<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">from
PyQt4.QtGui import *<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">from qgis.core
import *<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">from qgis.gui
import *<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">def
my_form_open(dialog, layer, feature):<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">
geom = feature.geometry()<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">
parishField = dialog.findChild(QLineEdit, "parish")<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">
for lyr in
QgsMapLayerRegistry.instance().mapLayers().values():<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">
if lyr.name() == 'parishes':<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">
for f in lyr.getFeatures():<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">
if geom.intersects(f.geometry()):<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">
parishField.setText(f.attribute('name'))<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">
break<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">
break<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">This works fine
using the identify tool but throws up the following error
when opening the attribute table:<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span
style="font-size:12.0pt;font-family:"Times New
Roman","serif";color:red;mso-fareast-language:EN-GB">An
error occurred during execution of following code:<br>
</span><span style="font-size:12.0pt;font-family:"Courier
New,courier","serif";color:red;mso-fareast-language:EN-GB">my_form_open(
_qgis_featureform_22_16,
_qgis_layer_test_lines20160503150512486_16,
_qgis_feature_20160503154237941)</span><span
style="font-size:12.0pt;font-family:"Times New
Roman","serif";color:windowtext;mso-fareast-language:EN-GB"><o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:12.0pt;font-family:"Courier
New,courier","serif";color:windowtext;mso-fareast-language:EN-GB"><br>
Traceback (most recent call last):<br>
File "", line 1, in <br>
File "", line 23, in my_form_open<br>
AttributeError: 'NoneType' object has no attribute
'intersects'<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:12.0pt;font-family:"Courier
New,courier","serif";color:windowtext;mso-fareast-language:EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span
style="font-size:12.0pt;font-family:"Courier
New,courier","serif";color:windowtext;mso-fareast-language:EN-GB">I
can see why the error is happening: When opening the
attribute table the feature is passed without geometry so
the intersect fails, but for my purposes I don’t want it to
be running the Python code anyway as I don’t want it
calculating fields unless I’ve actually clicked on the
feature. Opening the attribute table just runs it against
the first record in the table.<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:12.0pt;font-family:"Courier
New,courier","serif";color:windowtext;mso-fareast-language:EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span
style="font-size:12.0pt;font-family:"Courier
New,courier","serif";color:windowtext;mso-fareast-language:EN-GB">That’s
why I was hoping there’d be some way of detecting the
context of the form. QgsAttributeEditorContext has a
FormMode that returns Embed, StandaloneDialog or Popup, so I
thought that looked promising but I can’t work out how to
access it.<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:12.0pt;font-family:"Courier
New,courier","serif";color:windowtext;mso-fareast-language:EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Thanks<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Tom<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<div>
<div style="border:none;border-top:solid #B5C4DF
1.0pt;padding:3.0pt 0cm 0cm 0cm">
<p class="MsoNormal"><b><span
style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext;mso-fareast-language:EN-GB"
lang="EN-US">From:</span></b><span
style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext;mso-fareast-language:EN-GB"
lang="EN-US"> Matthias Kuhn [<a class="moz-txt-link-freetext" href="mailto:matthias@opengis.ch">mailto:matthias@opengis.ch</a>]
<br>
<b>Sent:</b> 03 May 2016 13:52<br>
<b>To:</b> Thomas Colley; <a class="moz-txt-link-abbreviated" href="mailto:qgis-user@lists.osgeo.org">qgis-user@lists.osgeo.org</a><br>
<b>Subject:</b> Re: [Qgis-user] Python form logic on
attribute table open<o:p></o:p></span></p>
</div>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal" style="margin-bottom:12.0pt">Hi Tom,<br>
<br>
Globals are really for "there will only ever be one of these"
objects. And that's not true for feature forms.<br>
You will have the same kind of trouble if the user opens the
feature form of two features in parallel because they will
work on the same global variable (which will be overwritten
and may even be deleted by form A whil form B is still open).<br>
<br>
I assume you have a slot connected to some widget's changed
signal and need the reference to parameters inside the slot.
It's best to pass them as parameters to the slot.<br>
<br>
Something like:<br>
<br>
----------<br>
<br>
import functools<br>
<br>
def my_slot( my_form, new_text ):<br>
do_something_with(my_control)<br>
print new_text<br>
<br>
def form_init(form, y, z):<br>
control.textChanged.connect(functools.partial(my_slot,
form))<br>
<br>
----------<o:p></o:p></p>
<div>
<p class="MsoNormal">On 05/03/2016 01:50 PM, Thomas Colley
wrote:<o:p></o:p></p>
</div>
<blockquote style="margin-top:5.0pt;margin-bottom:5.0pt">
<p class="MsoNormal"><span style="color:#1F497D">Hi Matthias</span><o:p></o:p></p>
<p class="MsoNormal"><span style="color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="color:#1F497D">I am using
global variables. In what way do they cause problems?</span><o:p></o:p></p>
<p class="MsoNormal"><span style="color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="color:#1F497D">Is it
expected behaviour for the Python logic to be used when
the attribute table is opened?</span><o:p></o:p></p>
<p class="MsoNormal"><span style="color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="color:#1F497D">I know what
is causing the Python error. I am performing an intersect
query to populate an attribute. When I open the attribute
table the first feature in the attribute table is being
passed to the Python form object but it doesn’t include
the geometry. This gives </span><span
style="font-family:"Courier New"">AttributeError:
'NoneType' object has no attribute 'intersects'.</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-family:"Courier
New""> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="color:#1F497D">I have no
need for any of the Python logic on opening of the
attribute table, although I can see the advantage if it
was open in form view.</span><o:p></o:p></p>
<p class="MsoNormal"><span style="color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="color:#1F497D">Hope this
makes sense, if you have any more details on the global
variables I’d be grateful.</span><o:p></o:p></p>
<p class="MsoNormal"><span style="color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="color:#1F497D">Thanks</span><o:p></o:p></p>
<p class="MsoNormal"><span style="color:#1F497D"><br>
Tom</span><o:p></o:p></p>
<p class="MsoNormal"><span style="color:#1F497D"> </span><o:p></o:p></p>
<div>
<div style="border:none;border-top:solid #B5C4DF
1.0pt;padding:3.0pt 0cm 0cm 0cm">
<p class="MsoNormal"><b><span
style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext;mso-fareast-language:EN-GB"
lang="EN-US">From:</span></b><span
style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext;mso-fareast-language:EN-GB"
lang="EN-US"> Qgis-user [<a moz-do-not-send="true"
href="mailto:qgis-user-bounces@lists.osgeo.org">mailto:qgis-user-bounces@lists.osgeo.org</a>]
<b>On Behalf Of </b>Matthias Kuhn<br>
<b>Sent:</b> 03 May 2016 09:45<br>
<b>To:</b> <a moz-do-not-send="true"
href="mailto:qgis-user@lists.osgeo.org">qgis-user@lists.osgeo.org</a><br>
<b>Subject:</b> Re: [Qgis-user] Python form logic on
attribute table open</span><o:p></o:p></p>
</div>
</div>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal" style="margin-bottom:12.0pt">Hi Tom,<br>
<br>
Are you using global variables? They often lead to troubles
in this context.<br>
<br>
Matthias<o:p></o:p></p>
<div>
<p class="MsoNormal">On 05/03/2016 10:42 AM, Thomas Colley
wrote:<o:p></o:p></p>
</div>
<blockquote style="margin-top:5.0pt;margin-bottom:5.0pt">
<p class="MsoNormal">Hi<o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal">I have a Python init function bound to
an attribute form. This is working great using the
identify tool to open a feature form but is throwing an
error when I open the layer’s attribute table.<o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal">Is there any way I can check in the
Python whether a feature form has been opened or the
attribute table. I have no need for the logic when opening
the attribute table.<o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal">I’ve found QgsAttributeEditorContext
that looks like it might do the trick but I can’t work out
how to access it.<o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal">Any advice would be appreciated.<o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal">Thanks<o:p></o:p></p>
<p class="MsoNormal"><br>
Tom<o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:12.0pt"><br>
<br>
<br>
<br>
</span><o:p></o:p></p>
<pre>_______________________________________________<o:p></o:p></pre>
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<p class="MsoNormal"><span style="font-size:12.0pt"><br>
<br>
<br>
</span><o:p></o:p></p>
<pre>-- <o:p></o:p></pre>
<pre>Matthias Kuhn<o:p></o:p></pre>
<pre>OPENGIS.ch - <a moz-do-not-send="true" href="https://www.opengis.ch">https://www.opengis.ch</a><o:p></o:p></pre>
<pre>Spatial • (Q)GIS • PostGIS • Open Source<o:p></o:p></pre>
</blockquote>
<p class="MsoNormal"><span
style="font-size:12.0pt;font-family:"Times New
Roman","serif";mso-fareast-language:EN-GB"><br>
<br>
<o:p></o:p></span></p>
<pre>-- <o:p></o:p></pre>
<pre>Matthias Kuhn<o:p></o:p></pre>
<pre>OPENGIS.ch - <a moz-do-not-send="true" href="https://www.opengis.ch">https://www.opengis.ch</a><o:p></o:p></pre>
<pre>Spatial • (Q)GIS • PostGIS • Open Source<o:p></o:p></pre>
</div>
</blockquote>
<br>
<pre class="moz-signature" cols="72">--
Matthias Kuhn
OPENGIS.ch - <a class="moz-txt-link-freetext" href="https://www.opengis.ch">https://www.opengis.ch</a>
Spatial • (Q)GIS • PostGIS • Open Source</pre>
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