Article Outline
Python pyqt (gui) example 'valuesource'
Modules used in program:
import QtQuick 2.0import People 1.0import sys
valuesource
Python pyqt example: valuesource
#!/usr/bin/env python
#############################################################################
##
## Copyright (C) 2013 Riverbank Computing Limited.
## Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
## All rights reserved.
##
## This file is part of the examples of PyQt.
##
## $QT_BEGIN_LICENSE:BSD$
## You may use this file under the terms of the BSD license as follows:
##
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## modification, are permitted provided that the following conditions are
## met:
## * Redistributions of source code must retain the above copyright
## notice, this list of conditions and the following disclaimer.
## * Redistributions in binary form must reproduce the above copyright
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## the documentation and/or other materials provided with the
## distribution.
## * Neither the name of Nokia Corporation and its Subsidiary(-ies) nor
## the names of its contributors may be used to endorse or promote
## products derived from this software without specific prior written
## permission.
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## THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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## $QT_END_LICENSE$
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#############################################################################
import sys
from PyQt5.QtCore import (pyqtProperty, pyqtSignal, pyqtSlot, Q_CLASSINFO,
QCoreApplication, QDate, QObject, QTime, QTimer, QUrl)
from PyQt5.QtGui import QColor
from PyQt5.QtQml import (qmlAttachedPropertiesObject, qmlRegisterType,
QQmlComponent, QQmlEngine, QQmlListProperty, QQmlProperty,
QQmlPropertyValueSource)
QML = b'''
import People 1.0
import QtQuick 2.0
BirthdayParty {
HappyBirthdaySong on announcement { name: "Bob Jones" }
onPartyStarted: console.log("This party started rockin' at " + time);
host: Boy {
name: "Bob Jones"
shoe { size: 12; color: "white"; brand: "Nike"; price: 90.0 }
}
Boy {
name: "Leo Hodges"
BirthdayParty.rsvp: "2009-07-06"
shoe { size: 10; color: "black"; brand: "Reebok"; price: 59.95 }
}
Boy {
name: "Jack Smith"
shoe { size: 8; color: "blue"; brand: "Puma"; price: 19.95 }
}
Girl {
name: "Anne Brown"
BirthdayParty.rsvp: "2009-07-01"
shoe.size: 7
shoe.color: "red"
shoe.brand: "Marc Jacobs"
shoe.price: 699.99
}
}
'''
class ShoeDescription(QObject):
def __init__(self, parent=None):
super(ShoeDescription, self).__init__(parent)
self._size = 0
self._color = QColor()
self._brand = ''
self._price = 0.0
shoeChanged = pyqtSignal()
@pyqtProperty(int, notify=shoeChanged)
def size(self):
return self._size
@size.setter
def size(self, size):
if self._size != size:
self._size = size
self.shoeChanged.emit()
@pyqtProperty(QColor, notify=shoeChanged)
def color(self):
return self._color
@color.setter
def color(self, color):
if self._color != color:
self._color = color
self.shoeChanged.emit()
@pyqtProperty(str, notify=shoeChanged)
def brand(self):
return self._brand
@brand.setter
def brand(self, brand):
if self._brand != brand:
self._brand = brand
self.shoeChanged.emit()
@pyqtProperty(float, notify=shoeChanged)
def price(self):
return self._price
@price.setter
def price(self, price):
if self._price != price:
self._price = price
self.shoeChanged.emit()
class Person(QObject):
def __init__(self, parent=None):
super(Person, self).__init__(parent)
self._name = ''
self._shoe = ShoeDescription()
nameChanged = pyqtSignal()
@pyqtProperty(str, notify=nameChanged)
def name(self):
return self._name
@name.setter
def name(self, name):
if self._name != name:
self._name = name
self.nameChanged.emit()
@pyqtProperty(ShoeDescription)
def shoe(self):
return self._shoe
class Boy(Person):
pass
class Girl(Person):
pass
class BirthdayPartyAttached(QObject):
def __init__(self, parent):
super(BirthdayPartyAttached, self).__init__(parent)
self._rsvp = QDate()
rsvpChanged = pyqtSignal()
@pyqtProperty(QDate, notify=rsvpChanged)
def rsvp(self):
return self._rsvp
@rsvp.setter
def rsvp(self, rsvp):
if self._rsvp != rsvp:
self._rsvp = rsvp
self.rsvpChanged.emit()
class BirthdayParty(QObject):
Q_CLASSINFO('DefaultProperty', 'guests')
partyStarted = pyqtSignal(QTime, arguments=['time'])
def __init__(self, parent=None):
super(BirthdayParty, self).__init__(parent)
self._host = None
self._guests = []
hostChanged = pyqtSignal()
@pyqtProperty(Person, notify=hostChanged)
def host(self):
return self._host
@host.setter
def host(self, host):
if self._host != host:
self._host = host
self.hostChanged.emit()
@pyqtProperty(QQmlListProperty)
def guests(self):
return QQmlListProperty(Person, self, self._guests)
@pyqtProperty(str)
def announcement(self):
return ''
@announcement.setter
def announcement(self, announcement):
print(announcement)
def startParty(self):
self.partyStarted.emit(QTime.currentTime())
class HappyBirthdaySong(QObject, QQmlPropertyValueSource):
def __init__(self, parent=None):
super(HappyBirthdaySong, self).__init__(parent)
self._line = -1
self._lyrics = []
self._target = QQmlProperty()
self._name = ''
timer = QTimer(self)
timer.timeout.connect(self.advance)
timer.start(1000)
nameChanged = pyqtSignal()
@pyqtProperty(str, notify=nameChanged)
def name(self):
return self._name
@name.setter
def name(self, name):
if self._name != name:
self._name = name
self._lyrics = [
"",
"Happy birthday to you,",
"Happy birthday to you,",
"Happy birthday dear %s," % self._name,
"Happy birthday to you!"
]
self.nameChanged.emit()
def setTarget(self, target):
self._target = target
@pyqtSlot()
def advance(self):
self._line += 1
if self._line < len(self._lyrics):
self._target.write(self._lyrics[self._line])
else:
QCoreApplication.instance().quit()
app = QCoreApplication(sys.argv)
qmlRegisterType(BirthdayPartyAttached)
qmlRegisterType(BirthdayParty, "People", 1, 0, "BirthdayParty",
attachedProperties=BirthdayPartyAttached)
qmlRegisterType(HappyBirthdaySong, "People", 1, 0, "HappyBirthdaySong")
qmlRegisterType(ShoeDescription)
qmlRegisterType(Person)
qmlRegisterType(Boy, "People", 1, 0, "Boy")
qmlRegisterType(Girl, "People", 1, 0, "Girl")
engine = QQmlEngine()
component = QQmlComponent(engine)
component.setData(QML, QUrl())
party = component.create()
if party is not None and party.host is not None:
print("\"%s\" is having a birthday!" % party.host.name)
if isinstance(party.host, Boy):
print("He is inviting:")
else:
print("She is inviting:")
for guest in party.guests:
attached = qmlAttachedPropertiesObject(BirthdayParty, guest, False)
if attached is not None:
rsvpDate = attached.property('rsvp')
else:
rsvpDate = QDate()
if rsvpDate.isNull():
print(" \"%s\" RSVP date: Hasn't RSVP'd" % guest.name)
else:
print(" \"%s\" RSVP date: %s" % (guest.name, rsvpDate.toString()))
party.startParty()
else:
for e in component.errors():
print("Error:", e.toString());
sys.exit(app.exec_())
Useful links
- Learn PyQt: https://pythonbasics.org/pyqt-hello-world/
- Install PyQt: https://pythonbasics.org/install-pyqt/