[Qgis-user] QCompleter in QGIS form

[Blumentrath, Stefan]

Hi Matthias,

Wow, cool! Thanks for implementing that so fast!

I just tested caching in a global variable. It works like a charm and speeds up the GUI significantly.

And yes, the completer works fine with autogenerated forms too (I only had to restart QGIS).
So all my problems in this regards are solved now.

The only, minor issue is, that one has to set Settings->Options->Enable Macros to "Always", or "Only this session" (with "Ask" (the default setting) the startup macro does not load, see: http://hub.qgis.org/issues/9523)

For those who are interested and who can`t wait for the next release with Matthias additions (and who like me are absolute Python beginners),
here is how it works (quite simple actually once you know how to do it):

The openProject() Python marco function (in my case named generate_completer.py, located in the project directory)
looks like this (completer content could also be loaded from file of course):
-----------------------------
#!/usr/bin/env python

from PyQt4.QtCore import *
from qgis.core import *
import psycopg2

def fetch_citems():

    global ci
    #Fetch data from DB to fill completer
    conn = psycopg2.connect("dbname='MYDB' user='MYUSER' host='MYHOST' password='MYDB'")
    cur = conn.cursor()
    cur.execute("""SELECT scientificname FROM kls.l_artsliste WHERE finnesinorge = 'Ja'""")
    ci = []
    for row in cur.fetchall():
        ci.append(row[0])

-----------------------------

It is referenced in the project like this:
    import generate_completer
    generate_completer.fetch_citems()

And the form init function (in my case named completer.py, located in the project directory) looks like this:
-----------------------------

from PyQt4.QtCore import *
from PyQt4.QtGui import *
import generate_completer

nameField = None
myDialog = None

def formOpen(dialog,layerid,featureid):
    global myDialog
    myDialog = dialog
    global nameField
    nameField = dialog.findChild(QLineEdit,"latinn")

    #Initiate completer
    completer = QCompleter()
    nameField.setCompleter(completer)

    #Add data to Qt Model / QCompleter
    model = QStringListModel()
    model.setStringList(generate_completer.ci)
    completer.setModel(model)

-----------------------------

It is referenced in the Fields tab as: completer.formOpen
"latinn" is the name of the attribute column BTW for which the completer is used.

I guess the global variable "ci" (Python list with Unicode strings) could also be used for data validation (in Nathan`s example)...

Thanks for this amazing Software!

Kind regards,
Stefan

From: qgis-user-bounces at lists.osgeo.org [mailto:qgis-user-bounces at lists.osgeo.org] On Behalf Of Matthias Kuhn
Sent: 29. mars 2015 19:56
To: qgis-user at lists.osgeo.org
Subject: Re: [Qgis-user] QCompleter in QGIS form

Hi Stefan,

I had some spare time on the Sunday evening train. So I have just added this possibility to the ValueRelation widget. You can now choose the option "Use Completer" there.
The query is still run every time the form is opened at the moment. There is actually a caching mechanism for the value relation widget prepared, so it should be possible to make use of that and initialize the cache only once.
But that will have to wait until I have some spare time again or one may speed up the process by funding this or tackling the issue if coding skills are available (for the last option, please get in touch first, there are a couple of different approaches to doing this),

Testing is appreciated.
Matthias
On 03/28/2015 08:32 PM, Blumentrath, Stefan wrote:
Dear all,

Thanks to Nathan`s excellent example here:
http://nathanw.net/2011/09/05/qgis-tips-custom-feature-forms-with-python-logic/
I managed to implement a simple QCompleter for a LineEdit in my form where the completer items are being fetched from DB (see init function code at the end of my mail).

This is very, very promising stuff which comes in quite handy for entering species names (from an official list of (thousands of) species names in my case)!

Yet there are two things I am struggling with:
1) Would it be possible to use this QCompleter solution to an autogenerated form? The auto generated forms are more than good enough for most of my use-cases. When I tried the Init function on an autogenerated form I got "NameError: global name 'TextEdit' is not defined"... Any ideas how to fix that?

2) It seems to me that the query - which is used to fill the QCompleter - is executed each time the form is opened. Would it be possible to avoid this, I mean that the query is only run once (e.g. when I open the project)? I hoped this could speed up the start of the form (even if the query gets cached in PostgreSQL)...
Many thanks in advance for helping.

Kind regards,
Stefan

P.S.: Next thing I will have to do is understand SIGNALS and SLOTS so I can adjust the completer content depending on other data entered in the form (e.g. filter species by kingdom or known occurrence in a country (here Norway)) ...

P.P.S.: My form_init.py looks like this:

from PyQt4.QtCore import *
from PyQt4.QtGui import *
from PyQt4.QtSql import *
import psycopg2
nameField = None
myDialog = None

def formOpen(dialog,layerid,featureid):
    global myDialog
    myDialog = dialog
    global nameField
    nameField = dialog.findChild(QLineEdit,"latinsk_navn")

    #Initiate completer
    completer = QCompleter()
    nameField.setCompleter(completer)

    #Fetch data from DB to fill completer
    conn = psycopg2.connect("dbname='MYDB' user='MYUSERNAME' host='MYHOST' password='MYPASSWD'")
    cur = conn.cursor()
    cur.execute("""SELECT scientificname FROM kls.l_artsliste WHERE finnesinorge = 'Ja'""")
    completition_items = []
    for row in cur.fetchall():
        completition_items.append(row[0])

               #Add data to Qt Model / QCompleter
               model = QStringListModel()
    model.setStringList(completition_items)
    completer.setModel(model)




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