attribute-formdata-defined-overrideqgisrule-based
In QGIS attribute form Drag and Drop Designer we can choose a backgroud color for widget containers (Tabs and Group boxes):
Is it possible to have rule based background colors depending on some attribute value, i.e. some sort of data defined override?
I thought of a Python macro too, which sets the background color when a form loads, but I was not able to figure out how to adress the required container widget.
This is an example of Python Code:
from PyQt4.QtGui import *
# define some rules: label, expression, color name, width
my_rules = (
('Feature one', '"type" LIKE \'first\'', 'green', 2),
('Feature two', '"type" LIKE \'second\'', 'red', 2),
('Feature three', '"type" LIKE \'third\'', 'blue', 2),
)
layer = iface.activeLayer()
# create a new rule-based renderer
symbol = QgsSymbolV2.defaultSymbol(layer.geometryType())
renderer = QgsRuleBasedRendererV2(symbol)
# get the "root" rule
root_rule = renderer.rootRule()
for label, expression, color_name, width in my_rules:
# create a clone (i.e. a copy) of the default rule
rule = root_rule.children()[0].clone()
# set the label, expression and color
rule.setLabel(label)
rule.setFilterExpression(expression)
rule.symbol().setColor(QColor(color_name))
rule.symbol().setWidth(width)
# append the rule to the list of rules
root_rule.appendChild(rule)
# delete the default rule
root_rule.removeChildAt(0)
# apply the renderer to the layer
layer.setRendererV2(renderer)
iface.mapCanvas().refresh()
I tested it with this line vector layer ('expression' in field 'type'):
After run the code in the Python Console of QGIS (line2 as Active Layer):
Your formula goes to "label with" ... not in the "filter" field ...
Best Answer
If you check the box above (Control visibility by expression) and setup your rules carefully, you should be able to obtain what you are looking for.
For example : In a table with a field called value, with value between 1 and 5, and three rules with corresponding background color:
I create as many container (green + sign) as I need rules (three here). In each of the container, I check Control Visibility by Expression and setup an expression corresponding to the specific value I want in that container.
Then, if I open the form, the container with the rule matching the value will be visible :