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<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>
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<p class="MsoNormal"><b><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext;mso-fareast-language:EN-GB">From:</span></b><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext;mso-fareast-language:EN-GB">
Matthias Kuhn [mailto:matthias@opengis.ch] <br>
<b>Sent:</b> 03 May 2016 13:52<br>
<b>To:</b> Thomas Colley; qgis-user@lists.osgeo.org<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>
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<p class="MsoNormal"><b><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext;mso-fareast-language:EN-GB">From:</span></b><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext;mso-fareast-language:EN-GB">
Qgis-user [<a 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 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>
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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 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 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>
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