I built Python3/Qt5 styled example to test out a StyleSheet class I'm writing.
I also fixed an issue with size calculations that didn't consider size changes to the expander button.
I also changed the method to setLayout() to be consistent with Qt.
import sys
import inspect
import textwrap
from collections import OrderedDict, UserString
from PyQt5 import QtCore, QtGui
from PyQt5.QtCore import Qt
from PyQt5.QtGui import QIcon
from PyQt5.QtWidgets import *
class QStyleSheet(UserString):
"""
Represent stylesheets as dictionary key value pairs.
Update complex stylesheets easily modifying only the attributes you need
Allow for attribute inheritance or defaulting of stylesheets.
# TODO support [readOnly="true"] attribute-selectors
QTextEdit, QListView <-- you can have multiple classes.
QCheckBox::indicator <-- some psuedo classes have double colons
"""
def __init__(self, cls=None, name=None, psuedo=None, **styles):
"""
Arguments to the constructor allow you to default different properties of the CSS Class.
Any argument defined here will be global to this StyleSheet and cannot be overidden later.
:param cls: Default style prefix class to ``cls``
:param name: Default object name to ``name`` (hashtag) is not needed.
:param psuedo: Default psuedo class to ``psuedo``, example: ``:hover``
"""
self.cls_scope = cls
self.psuedo_scope = psuedo
self.name_scope = name
self._styles = OrderedDict() # we'll preserve the order of attributes given - python 3.6+
if styles:
self.setStylesDict(OrderedDict(styles))
def _ident(self, cls=None, name=None, psuedo=None):
# -- ensure value is of correct type ----------------------------------------
if cls is not None and not inspect.isclass(cls):
raise ValueError(f'cls must be None or a class object, got: {type(cls)}')
if name is not None and not isinstance(name, str):
raise ValueError(f'name must be None or a str, got: {type(name)}')
if psuedo is not None and not isinstance(psuedo, str):
raise ValueError(f'psuedo must be None or a str, got: {type(psuedo)}')
# -- ensure not overiding defaults -------------------------------------------
if cls is not None and self.cls_scope is not None:
raise ValueError(f'cls was set in __init__, you cannot override it')
if name is not None and self.name_scope is not None:
raise ValueError(f'name was set in __init__, you cannot override it')
if psuedo is not None and self.psuedo_scope is not None:
raise ValueError(f'psuedo was set in __init__, you cannot override it')
# -- apply defaults if set ---------------------------------------------------
if cls is None and self.cls_scope is not None:
cls = self.cls_scope
if name is None and self.name_scope is not None:
name = self.name_scope
if psuedo is None and self.psuedo_scope is not None:
psuedo = self.psuedo_scope
# return a tuple that can be used as a dictionary key.
ident = tuple([getattr(cls, '__name__', None), name or None, psuedo or None])
return ident
def _class_definition(self, ident):
"""Get the class definition string"""
cls, name, psuedo = ident
return '%s%s%s' % (cls or '', name or '', psuedo or '')
def _fix_underscores(self, styles):
return OrderedDict([(k.replace('_', '-'), v) for k,v in styles.items()])
def setStylesStr(self, styles):
"""
Parse styles from a string and set them on this object.
"""
raise NotImplementedError()
self._update()
def setStylesDict(self, styles, cls=None, name=None, psuedo=None):
"""
Set styles using a dictionary instead of keyword arguments
"""
styles = self._fix_underscores(styles)
if not isinstance(styles, dict):
raise ValueError(f'`styles` must be dict, got: {type(styles)}')
if not styles:
raise ValueError('`styles` cannot be empty')
ident = self._ident(cls, name, psuedo)
stored = self._styles.get(ident, OrderedDict())
stored.update(styles)
self._styles[ident] = stored
self._update()
def setStyles(self, cls=None, name=None, psuedo=None, **styles):
"""
Set or update styles according to the CSS Class definition provided by (cls, name, psuedo) using keyword-arguments.
Any css attribute with a hyphen ``-`` character should be changed to an underscore ``_`` when passed as a keyword argument.
Example::
Lets suppose we want to create the css class:
QFrame#BorderTest { background-color: white; margin:4px; border:1px solid #a5a5a5; border-radius: 10px;}
>>> stylesheet.setStyle(cls=QFrameBorderTest, background_color='white', margin='4px', border_radius='10px')
>>> print(stylesheet)
QFrame#BorderTest { background-color: white; margin:4px; border:1px solid #a5a5a5; border-radius: 10px;}
"""
styles = OrderedDict(styles)
self.setStylesDict(styles=styles, cls=cls, name=name, psuedo=psuedo)
def getStyles(self, cls=None, name=None, psuedo=None):
"""
Return the dictionary representations of styles for the CSS Class definition provided by (cls, name, psuedo)
:returns: styles dict (keys with hyphens)
"""
ident = self._ident(cls, name, psuedo)
return self._styles.get(ident)
def getClassIdents(self):
"""Get all class identifier tuples"""
return list(self._styles.keys())
def getClassDefinitions(self):
"""Get all css class definitions, but not the css attributes/body"""
return [self._class_definition(ident) for ident in self.getClassIdents()]
def validate(self):
"""
Validate all the styles and attributes on this class
"""
raise NotImplementedError()
def merge(self, stylesheet, overwrite=True):
"""
Merge another QStyleSheet with this QStyleSheet.
The QStyleSheet passed as an argument will be left un-modified.
:param overwrite: if set to True the matching class definitions will be overwritten
with attributes and values from ``stylesheet``.
Otherwise, the css attributes will be updated from ``stylesheet``
:type overwrite: QStyleSheet
"""
for ident in stylesheet.getClassIdents():
styles = stylesheet.getStyles(ident)
cls, name, psuedo = ident
self.setStylesDict(styles, cls=cls, name=name, psuedo=psuedo)
self._update()
def clear(self, cls=None, name=None, psuedo=None):
"""
Clear styles matching the Class definition
The style dictionary cleared will be returned
None will be returned if nothing was cleared.
"""
ident = self._ident(cls, name, psuedo)
return self._styles.pop(ident, None)
def _update(self):
"""Update the internal string representation"""
stylesheet = []
for ident, styles in self._styles.items():
if not styles:
continue
css_cls = self._class_definition(ident)
css_cls = css_cls + ' ' if css_cls else ''
styles_str = '\n'.join([f'{k}: {v};' for k, v in styles.items()])
styles_str = textwrap.indent(styles_str, ''.ljust(4))
stylesheet.append('%s{\n%s\n}' % (css_cls, styles_str))
self.data = '\n\n'.join(stylesheet)
class Expander(QWidget):
def __init__(self, parent=None, title=None, animationDuration=200):
super().__init__(parent=parent)
self.animationDuration = animationDuration
self.toggleAnimation = QtCore.QParallelAnimationGroup()
self.contentArea = QScrollArea()
self.headerLine = QFrame()
self.toggleButton = QToolButton()
self.mainLayout = QGridLayout()
toggleButton = self.toggleButton
self.toggleButtonQStyle = QStyleSheet(QToolButton, border='none')
toggleButton.setStyleSheet(str(self.toggleButtonQStyle))
toggleButton.setToolButtonStyle(QtCore.Qt.ToolButtonTextBesideIcon)
toggleButton.setArrowType(QtCore.Qt.RightArrow)
toggleButton.setText(title or '')
toggleButton.setCheckable(True)
toggleButton.setChecked(False)
toggleButton.setSizePolicy(QSizePolicy.Minimum, QSizePolicy.Minimum)
headerLine = self.headerLine
self.headerLineQStyle = QStyleSheet(QFrame)
headerLine.setFrameShape(QFrame.NoFrame) # see: https://doc.qt.io/archives/qt-4.8/qframe.html#Shape-enum
headerLine.setFrameShadow(QFrame.Plain) # see: https://doc.qt.io/archives/qt-4.8/qframe.html#Shape-enum
headerLine.setSizePolicy(QSizePolicy.Expanding, QSizePolicy.Maximum)
self.contentAreaQStyle = QStyleSheet(QScrollArea, border='none')
self.contentArea.setStyleSheet(str(self.contentAreaQStyle))
self.contentArea.setSizePolicy(QSizePolicy.Expanding, QSizePolicy.Fixed)
# start out collapsed
self.contentArea.setMaximumHeight(0)
self.contentArea.setMinimumHeight(0)
# let the entire widget grow and shrink with its content
toggleAnimation = self.toggleAnimation
toggleAnimation.addAnimation(QtCore.QPropertyAnimation(self, b"minimumHeight"))
toggleAnimation.addAnimation(QtCore.QPropertyAnimation(self, b"maximumHeight"))
toggleAnimation.addAnimation(QtCore.QPropertyAnimation(self.contentArea, b"maximumHeight"))
# don't waste space
mainLayout = self.mainLayout
mainLayout.setVerticalSpacing(0)
mainLayout.setContentsMargins(0, 0, 0, 0)
row = 0
mainLayout.addWidget(self.toggleButton, row, 0, 1, 1, QtCore.Qt.AlignLeft)
mainLayout.addWidget(self.headerLine, row, 2, 1, 1)
row += 1
mainLayout.addWidget(self.contentArea, row, 0, 1, 3)
super().setLayout(self.mainLayout)
def start_animation(checked):
arrow_type = QtCore.Qt.DownArrow if checked else QtCore.Qt.RightArrow
direction = QtCore.QAbstractAnimation.Forward if checked else QtCore.QAbstractAnimation.Backward
toggleButton.setArrowType(arrow_type)
self.toggleAnimation.setDirection(direction)
self.toggleAnimation.start()
self.toggleButton.clicked.connect(start_animation)
def setHeaderFrameStyles(self, styles):
self._setWidgetStyles(self.headerLine, self.headerLineQStyle, styles)
def setToggleButtonStyles(self, styles):
self._setWidgetStyles(self.toggleButton, self.toggleButtonQStyle, styles)
def setContentAreaStyles(self, styles):
self._setWidgetStyles(self.contentArea, self.contentAreaQStyle, styles)
def _setWidgetStyles(self, widget, qstylesheet, var):
if isinstance(var, QStyleSheet):
qstylesheet.merge(var)
widget.setStyleSheet(str(qstylesheet))
elif isinstance(var, dict):
qstylesheet.setStylesDict(var)
widget.setStyleSheet(str(qstylesheet))
elif isinstance(var, str):
widget.setStyleSheet(var)
else:
raise ValueError('invalid argument type: {type(var)}')
def setLayout(self, contentLayout):
"""
Set the layout container that you would like to expand/collapse.
This should be called after all styles are set.
"""
# Not sure if this is equivalent to self.contentArea.destroy()
self.contentArea.destroy()
self.contentArea.setLayout(contentLayout)
collapsedHeight = self.toggleButton.sizeHint().height()
contentHeight = contentLayout.sizeHint().height()
for i in range(self.toggleAnimation.animationCount()-1):
spoilerAnimation = self.toggleAnimation.animationAt(i)
spoilerAnimation.setDuration(self.animationDuration)
spoilerAnimation.setStartValue(collapsedHeight)
spoilerAnimation.setEndValue(collapsedHeight + contentHeight)
contentAnimation = self.toggleAnimation.animationAt(self.toggleAnimation.animationCount() - 1)
contentAnimation.setDuration(self.animationDuration)
contentAnimation.setStartValue(0)
contentAnimation.setEndValue(contentHeight)
class MainWindow(QMainWindow):
LIGHT_BLUE = '#148cc1'
MED_BLUE = '#0c6a94'
DARK_BLUE = '#0a3a6b'
PALE_SALMON = '#fd756d'
LIGHT_GREY = '#d2d5da'
SLATE = '#525863'
def __init__(self):
super().__init__()
self.WINDOW_STYLE = QStyleSheet(QMainWindow, background_color=self.SLATE)
self.WINDOW_STYLE = str(self.WINDOW_STYLE)
self.LABEL_STYLE = QStyleSheet(QLabel, color=self.DARK_BLUE, font_weight=400, font_size='9pt')
self.LABEL_STYLE = str(self.LABEL_STYLE)
# -- QPushButton stylesheet ---------------------
self.BUTTON_STYLE = s1 = QStyleSheet()
s1.setStyles(cls=QPushButton,
color='white',
font_weight=400,
border_style='solid',
padding='4px',
background_color=self.LIGHT_BLUE)
s1.setStyles(cls=QPushButton, psuedo=':pressed',
background_color=self.PALE_SALMON)
s1.setStyles(cls=QPushButton, psuedo=':focus-pressed',
background_color=self.PALE_SALMON)
s1.setStyles(cls=QPushButton, psuedo=':disabled',
background_color=self.LIGHT_GREY)
s1.setStyles(cls=QPushButton, psuedo=':checked',
background_color=self.PALE_SALMON)
s1.setStyles(cls=QPushButton, psuedo=':hover:!pressed:!checked',
background_color=self.MED_BLUE)
self.BUTTON_STYLE = str(self.BUTTON_STYLE)
self.BUTTON_GROUPBOX_STYLE = QStyleSheet(QGroupBox, border='none', font_weight='bold', color='white')
self.BUTTON_GROUPBOX_STYLE = str(self.BUTTON_GROUPBOX_STYLE)
self.TEXT_EDIT_STYLE = QStyleSheet(QTextEdit, color='white', border=f'1px solid {self.LIGHT_BLUE}', background_color=self.MED_BLUE)
self.TEXT_EDIT_STYLE = str(self.TEXT_EDIT_STYLE)
self.initUI()
def initUI(self):
contents_vbox = QVBoxLayout()
label_box = QHBoxLayout()
for text in ('hello', 'goodbye', 'adios'):
lbl = QLabel(text)
lbl.setStyleSheet(self.LABEL_STYLE)
lbl.setAlignment(Qt.AlignCenter)
label_box.addWidget(lbl)
button_group = QButtonGroup()
button_group.setExclusive(True)
button_group.buttonClicked.connect(self._button_clicked)
self.button_group = button_group
button_hbox = QHBoxLayout()
for _id, text in enumerate(('small', 'medium', 'large')):
btn = QPushButton(text)
btn.setCheckable(True)
btn.setStyleSheet(self.BUTTON_STYLE)
button_group.addButton(btn)
button_group.setId(btn, _id)
button_hbox.addWidget(btn)
button_group.buttons()[0].toggle()
text_area = QTextEdit()
text_area.setPlaceholderText('Type a greeting here')
text_area.setStyleSheet(self.TEXT_EDIT_STYLE)
contents_vbox.addLayout(label_box)
contents_vbox.addLayout(button_hbox)
contents_vbox.addWidget(text_area)
collapsible = Expander(self, 'Expander')
collapsible.setToggleButtonStyles({'padding': '4px', 'background-color': 'white'})
collapsible.setContentAreaStyles({'background-color': 'white'})
collapsible.setLayout(contents_vbox)
vbox = QVBoxLayout()
vbox.addWidget(collapsible)
vbox.setAlignment(Qt.AlignTop)
widget = QWidget()
widget.setLayout(vbox)
self.setCentralWidget(widget)
self.setGeometry(200, 200, 500, 400)
self.setWindowTitle('Expander')
self.setStyleSheet(self.WINDOW_STYLE)
self.show()
def _button_clicked(self, button):
"""
For the toggle behavior of a QButtonGroup to work you must
connect the clicked signal!
"""
print('button-active', self.button_group.id(button))
if __name__ == '__main__':
app = QApplication(sys.argv)
ex = MainWindow()
sys.exit(app.exec_())
