I want to trigger a function of a different class on press of a button. Something like this example How to emit custom Events to the Event Loop in PyQt.
But I also want to pass a parameter to that function everytime the button is clicked. How do I achieve that?
If you want to add additional arguments you can use functools.partial:
main.py
from PyQt5 import QtCore, QtWidgets
from globalobject import GlobalObject
import functools
class MainWindow(QtWidgets.QMainWindow):
def __init__(self, parent=None):
super().__init__(parent)
button = QtWidgets.QPushButton(text="Press me", clicked=self.on_clicked)
self.setCentralWidget(button)
#QtCore.pyqtSlot()
def on_clicked(self):
GlobalObject().dispatchEvent("hello")
class Widget(QtWidgets.QWidget):
def __init__(self, parent=None):
super().__init__(parent)
wrapper = functools.partial(self.foo, "foo", bar="baz")
GlobalObject().addEventListener("hello", wrapper)
self._label = QtWidgets.QLabel()
lay = QtWidgets.QVBoxLayout(self)
lay.addWidget(self._label)
def foo(self, foo, bar=None):
print(foo, bar)
self._label.setText(foo)
if __name__ == "__main__":
import sys
app = QtWidgets.QApplication(sys.argv)
w1 = MainWindow()
w2 = Widget()
w1.show()
w2.show()
sys.exit(app.exec_())
That logic can also be implemented in the library:
globalobject.py
from PyQt5 import QtCore
import functools
#functools.lru_cache()
class GlobalObject(QtCore.QObject):
def __init__(self):
super().__init__()
self._events = {}
def addEventListener(self, name, func, *, args=(), kwargs=None):
kwargs = kwargs or {}
if name not in self._events:
self._events[name] = []
self._events[name].append((func, args, kwargs))
def dispatchEvent(self, name):
functions = self._events.get(name, [])
for func, args, kwargs in functions:
wrapper = func
wrapper = functools.partial(func, *args, **kwargs)
QtCore.QTimer.singleShot(0, wrapper)
main.py
from PyQt5 import QtCore, QtWidgets
from globalobject import GlobalObject
class MainWindow(QtWidgets.QMainWindow):
def __init__(self, parent=None):
super().__init__(parent)
button = QtWidgets.QPushButton(text="Press me", clicked=self.on_clicked)
self.setCentralWidget(button)
#QtCore.pyqtSlot()
def on_clicked(self):
GlobalObject().dispatchEvent("hello")
class Widget(QtWidgets.QWidget):
def __init__(self, parent=None):
super().__init__(parent)
GlobalObject().addEventListener(
"hello", self.foo, args=("foo",), kwargs={"bar": "baz"}
)
self._label = QtWidgets.QLabel()
lay = QtWidgets.QVBoxLayout(self)
lay.addWidget(self._label)
def foo(self, foo, bar=None):
print(foo, bar)
self._label.setText(foo)
if __name__ == "__main__":
import sys
app = QtWidgets.QApplication(sys.argv)
w1 = MainWindow()
w2 = Widget()
w1.show()
w2.show()
sys.exit(app.exec_())
Update:
If you want to send arguments through the dispatchEvent method then you should use the following:
globalobject.py
from PyQt5 import QtCore
import functools
#functools.lru_cache()
class GlobalObject(QtCore.QObject):
def __init__(self):
super().__init__()
self._events = {}
def addEventListener(self, name, func):
if name not in self._events:
self._events[name] = []
self._events[name].append(func)
def dispatchEvent(self, name, *, args=(), kwargs=None):
kwargs = kwargs or {}
functions = self._events.get(name, [])
for func in functions:
wrapper = func
wrapper = functools.partial(func, *args, **kwargs)
QtCore.QTimer.singleShot(0, wrapper)
main.py
from PyQt5 import QtCore, QtWidgets
from globalobject import GlobalObject
class MainWindow(QtWidgets.QMainWindow):
def __init__(self, parent=None):
super().__init__(parent)
button = QtWidgets.QPushButton(text="Press me", clicked=self.on_clicked)
self.setCentralWidget(button)
self.counter = 0
#QtCore.pyqtSlot()
def on_clicked(self):
self.counter += 1
GlobalObject().dispatchEvent("hello", args=(self.counter,))
class Widget(QtWidgets.QWidget):
def __init__(self, parent=None):
super().__init__(parent)
GlobalObject().addEventListener("hello", self.foo)
self._label = QtWidgets.QLabel()
lay = QtWidgets.QVBoxLayout(self)
lay.addWidget(self._label)
def foo(self, x):
print(x)
self._label.setNum(x)
if __name__ == "__main__":
import sys
app = QtWidgets.QApplication(sys.argv)
w1 = MainWindow()
w2 = Widget()
w1.show()
w2.show()
sys.exit(app.exec_())
Related
I am newbie and in that project I am stuck at one point. How can I access functions in MainWindow class from another Window.
For example I need to access Main.list_refresh when Child_EditAccount.btn_EDIT_ACCOUNT_3.clicked . I tried something like signal & slot but doesn't work. I maked 3 different Window with pyQt Designer and I need to link the three together.
new.py
# Designs
from design import Ui_MainWindow
from design_addAccount import Ui_MainWindow_Add
from design_editAccount import Ui_MainWindow_Edit
# Modules
from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.QtCore import pyqtSignal, pyqtSlot
import sqlite3
con = sqlite3.connect('shorts.sqlite3')
cur = con.cursor()
class Main(QtWidgets.QMainWindow):
def __init__(self, parent=None):
super(Main, self).__init__()
self.ui = Ui_MainWindow()
self.ui.setupUi(self)
self.account_process = AccountProcess()
self.ui.lst_accounts.itemClicked.connect(self.account_process.edit_account)
self.ui.btn_delete_account.clicked.connect(self.account_process.delete_account)
self.ui.btn_edit_account.clicked.connect(self.account_process.edit_account)
self.ui.btn_add_account.clicked.connect(self.account_process.add_account)
self.ui.btn_refresh.clicked.connect(self.list_refresh)
self.refresh_trigger = Child_EditAccount()
self.refresh_trigger.buttonClicked.connect(self.list_refresh)
def list_refresh(self):
self.ui.lst_accounts.clear()
for row in cur.execute("SELECT * FROM users"):
self.ui.lst_accounts.addItem('%s' % (str(row[3])))
class Child_AddAccount(QtWidgets.QMainWindow,Ui_MainWindow_Add):
def __init__(self, parent=None):
super(Child_AddAccount, self).__init__()
self.ui = Ui_MainWindow_Add()
self.ui.setupUi(self)
class Child_EditAccount(QtWidgets.QMainWindow,Ui_MainWindow_Edit):
buttonClicked = pyqtSignal()
def __init__(self, parent=None):
super(Child_EditAccount, self).__init__()
self.ui = Ui_MainWindow_Edit()
self.ui.setupUi(self)
def edit_infos(self, username, password, nickname, id):
self.id = id
self.ui.txtBox_username_3.insert(username)
self.ui.txtBox_password_3.insert(password)
self.ui.txtBox_nickname_3.insert(nickname)
self.ui.btn_EDIT_ACCOUNT_3.clicked.connect(self.update_by_id)
def update_by_id(self):
cur.execute('UPDATE users SET username="%s", password="%s", nickname="%s" WHERE id=%s' % (self.ui.txtBox_username_3.text(), self.ui.txtBox_password_3.text(), self.ui.txtBox_nickname_3.text(), self.id))
con.commit()
self.buttonClicked.emit()
class AccountProcess(QtCore.QObject):
def add_account(self):
self.child_add = Child_AddAccount()
self.child_add.show()
print('Pressed edit button')
def delete_account(self):
print('Pressed delete button')
def edit_account(self, item):
self.child_edit = Child_EditAccount()
for i in cur.execute(f"SELECT * FROM users WHERE nickname=\"{item.text()}\";"):
self.child_edit.edit_infos(str(i[1]), str(i[2]), str(i[3]), str(i[0]))
self.child_edit.show()
if __name__ == "__main__":
import sys
app = QtWidgets.QApplication(sys.argv)
main = Main()
main.show()
sys.exit(app.exec_())
You can use a pyqtSignal to do what you want.
in the Child_EditAccount class add a pyqtsignal
class Child_EditAccount(QtWidgets.QMainWindow,Ui_MainWindow_Add):
buttonClicked = pyqtSignal()
def __init__(self, parent=None):
before the __init__, then when you need to trigger the function use
buttonClicked.emit()
in the function where the button is used in the Child_EditAccount class
Then in the main window, you can create a connection to a function via the pyqtsignal
self.Child_EditAccount.buttonClicked.connect(self.myfunction)
in the __init__ of the main class. where self.Child_EditAccount is the instance of your Child_EditAccount class and self.function is the function you want to trigger Main.list_refresh
You can also create a signal from QtDesigner itself when you create the Ui_MainWindow_Edit
https://doc.qt.io/qt-5/designer-connection-mode.html
be carefull, Child_EditAccount inherite from Ui_MainWindow_Add instead of Ui_MainWindow_Edit probably.
____
what you can also do is link the sigal of the button directly in the main program as in this little example
# Modules
from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.QtCore import pyqtSignal, pyqtSlot
class Main2(QtWidgets.QMainWindow):
def __init__(self, parent=None):
super(Main2, self).__init__()
self.centralWidget = QtWidgets.QWidget()
self.setCentralWidget(self.centralWidget)
self.but= QtWidgets.QPushButton('tdvfdbt')
self.l = QtWidgets.QHBoxLayout()
self.l.addWidget(self.but)
self.centralWidget.setLayout(self.l)
class Main(QtWidgets.QMainWindow):
def __init__(self, parent=None):
super(Main, self).__init__()
self.win = Main2()
self.a = self.win.show()
self.win.but.clicked.connect(self.myfunction)
def myfunction(self):
print('called from sub window')
if __name__ == '__main__':
import sys
app = QtWidgets.QApplication(sys.argv)
ex = Main(app)
ex.setWindowTitle('Model micro GUI')
# ex.showMaximized()
ex.show()
sys.exit(app.exec())
if you know the name of the button widget of the Child_EditAccount class you can link it via
self.Child_EditAccount.btn_EDIT_ACCOUNT_3.clicked.connect(self.myfunction)
##______
Put the pystsignal in the AccountProcess class
class AccountProcess(QtCore.QObject):
buttonClicked = pyqtSignal()
def add_account(self):
self.child_add = Child_AddAccount()
self.child_add.show()
print('Pressed edit button')
def delete_account(self):
print('Pressed delete button')
def edit_account(self, item):
self.child_edit = Child_EditAccount()
for i in cur.execute(f"SELECT * FROM users WHERE nickname=\"{item.text()}\";"):
self.child_edit.edit_infos(str(i[1]), str(i[2]), str(i[3]), str(i[0]))
self.child_edit.buttonClicked.connect(self.EmitAgain)
self.child_edit.show()
def EmitAgain(self):
self.buttonClicked.emit()
Then use it in the main class
class Main(QtWidgets.QMainWindow):
def __init__(self, parent=None):
super(Main, self).__init__()
self.ui = Ui_MainWindow()
self.ui.setupUi(self)
self.account_process = AccountProcess()
self.account_process.buttonClicked.connect(self.list_refresh)
I have the following code but it's complaining that I cannot access the UI data from my thread. In my example code below, What is the best way I can access the userInputString value so my threading can run?
self.nameField is a PyQt QLineEdit.
QObject::setParent: Cannot set parent, new parent is in a different thread
QPixmap: It is not safe to use pixmaps outside the GUI thread
QWidget::repaint: Recursive repaint detected
import myUI
class MainUIClass(QtGui.QMainWindow, myUI.Ui_MainWindow):
def __init__(self, parent=None):
super(MainUIClass, self).__init__(parent)
self.setupUi(self)
self.startbutton.clicked.connect(self.do_work)
self.workerThread = WorkerThread()
self.connect(self.workerThread, SIGNAL("myThreading()"), self.myThreading, Qt.DirectConnection)
def do_work(self):
self.userInputString = self.nameField.Text()
self.workerThread.start()
def myThreading(self):
if userInputString is not None:
#Do something
class WorkerThread(QThread):
def __init__(self, parent=None):
super(WorkerThread, self).__init__(parent)
def run(self):
self.emit(SIGNAL("myThreading()"))
if __name__ == '__main__':
a = QtGui.QApplication(sys.argv)
app = MainUIClass()
app.show()
a.exec_()
Not sure if it's what you need but here is a working QThread exemple using Qt5
import time
import sys
from PyQt5 import QtWidgets, QtGui, QtCore
class MainWindow(QtWidgets.QMainWindow):
def __init__(self, parent=None):
super(MainWindow, self).__init__(parent)
self.worker_thread = WorkerThread()
self.worker_thread.job_done.connect(self.on_job_done)
self.create_ui()
def create_ui(self):
self.button = QtWidgets.QPushButton('Test', self)
self.button.clicked.connect(self.start_thread)
layout = QtWidgets.QVBoxLayout(self)
layout.addWidget(self.button)
def start_thread(self):
self.worker_thread.gui_text = self.button.text()
self.worker_thread.start()
def on_job_done(self, generated_str):
print("Generated string : ", generated_str)
self.button.setText(generated_str)
class WorkerThread(QtCore.QThread):
job_done = QtCore.pyqtSignal('QString')
def __init__(self, parent=None):
super(WorkerThread, self).__init__(parent)
self.gui_text = None
def do_work(self):
for i in range(0, 1000):
print(self.gui_text)
self.job_done.emit(self.gui_text + str(i))
time.sleep(0.5)
def run(self):
self.do_work()
if __name__ == '__main__':
app = QtWidgets.QApplication(sys.argv)
test = MainWindow()
test.show()
app.exec_()
when clicking a button in the PyQt5 Ui iam starting a mitmproxy. When the proxy is started, i try to change a listWidget with Data from the Proxy.
main.py
import sys
from PyQt5 import QtWidgets
from PyQt5.QtWidgets import QApplication, QMainWindow
from MainWindow import Ui_MainWindow
class MainWindow(QtWidgets.QMainWindow, Ui_MainWindow):
def __init__(self, *args, obj=None, **kwargs):
super(MainWindow, self).__init__(*args, **kwargs)
self.setupUi(self)
self.pushButton.clicked.connect(self.Start)
def Start(self):
x = threading.Thread(target=self.StartMITM)
x.start()
def StartMITM(self):
os.system("mitmweb -s mitmproxy.py -q --no-web-open-browser")
if __name__ == "__main__":
app = QApplication(sys.argv)
win = MainWindow()
win.show()
sys.exit(app.exec_())
mitmproxy.py - this is the error part
from mitmproxy import http
from main import MainWindow
def response(flow):
MainWindow.listWidget.addItem(flow.request.pretty_url)
Can I connect to the Widgets from another File?
It has 2 independent processes: The GUI and the mitmproxy script. And communicating both processes does not imply importing modules since you would be creating another widget, also objects should not be accessed through classes (I recommend you check your basic python notes).
In this the solution is to use some Inter process communication (IPC), in this case you can use Qt Remote Objects (QtRO):
main.py
from functools import cached_property
from PyQt5 import QtCore, QtRemoteObjects, QtWidgets
class Bridge(QtCore.QObject):
messageChanged = QtCore.pyqtSignal(str)
#QtCore.pyqtSlot(str)
def add_message(self, message):
self.messageChanged.emit(message)
class MitmwebManager(QtCore.QObject):
logChanged = QtCore.pyqtSignal(str)
def __init__(self, parent=None):
super().__init__(parent)
# self.process.setProcessChannelMode(QtCore.QProcess.MergedChannels)
self.process.readyReadStandardOutput.connect(self.handle_log)
self.process.setProgram("mitmweb")
#cached_property
def process(self):
return QtCore.QProcess()
def start(self, arguments):
self.process.setArguments(arguments)
self.process.start()
def stop(self):
self.process.kill()
def handle_log(self):
data = self.process.readAllStandardOutput()
codec = QtCore.QTextCodec.codecForName("UTF-8")
message = codec.toUnicode(data)
self.logChanged.emit(message)
class MainWindow(QtWidgets.QMainWindow):
def __init__(self, parent=None):
super().__init__(parent)
self.button = QtWidgets.QPushButton("Start", checkable=True)
self.listwidget = QtWidgets.QListWidget()
self.logview = QtWidgets.QPlainTextEdit(readOnly=True)
central_widget = QtWidgets.QWidget()
self.setCentralWidget(central_widget)
lay = QtWidgets.QGridLayout(central_widget)
lay.addWidget(self.button, 0, 0, 1, 2)
lay.addWidget(self.listwidget, 1, 0)
lay.addWidget(self.logview, 1, 1)
self.register_node = QtRemoteObjects.QRemoteObjectRegistryHost(
QtCore.QUrl("local:registry")
)
self.source_node = QtRemoteObjects.QRemoteObjectHost(
QtCore.QUrl("local:replica"), QtCore.QUrl("local:registry")
)
self.source_node.enableRemoting(self.bridge, "bridge")
self.button.toggled.connect(self.handle_toggled)
self.mitmweb.logChanged.connect(self.handle_log_changed)
self.bridge.messageChanged.connect(self.handle_message_changed)
self.resize(640, 480)
#cached_property
def mitmweb(self):
return MitmwebManager()
#cached_property
def bridge(self):
return Bridge()
def handle_toggled(self, checked):
if checked:
self.mitmweb.start(["-s", "script.py", "--no-web-open-browser"])
self.button.setText("Stop")
else:
self.mitmweb.stop()
self.button.setText("Start")
def handle_log_changed(self, message):
self.logview.insertPlainText(message)
def closeEvent(self, event):
super().closeEvent(event)
self.mitmweb.stop()
def handle_message_changed(self, message):
item = QtWidgets.QListWidgetItem(message)
self.listwidget.addItem(item)
def main():
app = QtWidgets.QApplication([])
view = MainWindow()
view.show()
app.exec_()
if __name__ == "__main__":
main()
script.py
from mitmproxy import http
from PyQt5 import QtCore, QtRemoteObjects
class Bridge(QtCore.QObject):
def __init__(self, bridge, parent=None):
super().__init__(parent)
self._message = ""
self._bridge = bridge
self.bridge.initialized.connect(self.handle_initialized)
#property
def bridge(self):
return self._bridge
#property
def message(self):
return self._message
def send_message(self, message):
self._message = message
#QtCore.pyqtSlot()
def handle_initialized(self):
self.bridge.add_message(self._message)
QtCore.QTimer.singleShot(0, QtCore.QCoreApplication.quit)
def send_qt(message):
qt_app = QtCore.QCoreApplication([])
replica_node = QtRemoteObjects.QRemoteObjectNode(QtCore.QUrl("local:registry"))
replica_bridge = replica_node.acquireDynamic("bridge")
bridge = Bridge(replica_bridge)
bridge.send_message(message)
qt_app.exec_()
def response(flow):
send_qt(flow.request.pretty_url)
I have to activate some function, when the cursor is moving. So, I used self.setMouseTracking(True) in MainWidget. But in this way mouseMoveEvent() works only when there is an empty form under cursor. I tried to create another widget over main, but it doesnt work at all.
class ClickButton(QPushButton):
def __init__(self, text, window):
...
def run(self):
...
class Window(QWidget):
def __init__(self):
super().__init__()
self.setGeometry(0, 0, 1000, 1000)
self.setMouseTracking(True)
self.clickers = [ClickButton('OK', self) for i in range(8)]
def mouseMoveEvent(self, ev):
for e in self.clickers:
e.run()
Whats to do?
If you want to detect the position of the mouse even when the mouse is on top of a child, a possible option is to use an event filter.
from PyQt5 import QtCore, QtGui, QtWidgets
class Widget(QtWidgets.QWidget):
def __init__(self, parent=None):
super(Widget, self).__init__(parent)
w_ = QtWidgets.QWidget()
lay_w = QtWidgets.QHBoxLayout(w_)
for c in (QtWidgets.QPushButton(), QtWidgets.QLineEdit()):
lay_w.addWidget(c)
lay = QtWidgets.QVBoxLayout(self)
for w in (QtWidgets.QPushButton(), QtWidgets.QLineEdit(), QtWidgets.QTextEdit(), w_):
lay.addWidget(w)
for ws in self.findChildren(QtWidgets.QWidget) + [self]:
ws.setMouseTracking(True)
ws.installEventFilter(self)
def eventFilter(self, obj, event):
if event.type() == QtCore.QEvent.MouseMove:
p_respect_to_window = self.mapFromGlobal(obj.mapToGlobal(event.pos()))
print(p_respect_to_window)
return super(Widget, self).eventFilter(obj, event)
if __name__ == '__main__':
import sys
app = QtWidgets.QApplication(sys.argv)
w = Widget()
w.show()
sys.exit(app.exec_())
On the other hand if you only want to do it in only one type of custom widget it is better to overwrite the mouseMoveEvent method of the custom widget:
from PyQt5 import QtCore, QtGui, QtWidgets
class ClickButton(QtWidgets.QPushButton):
def __init__(self, text, parent=None):
super(ClickButton, self).__init__(text=text, parent=parent)
self.setMouseTracking(True)
def mouseMoveEvent(self, event):
self.run()
super(ClickButton, self).mouseMoveEvent(event)
def run(self):
print("call to run function in button{} and time: {}".format(self.text(),
QtCore.QDateTime.currentDateTime().toString()))
class Widget(QtWidgets.QWidget):
def __init__(self, parent=None):
super(Widget, self).__init__(parent)
lay = QtWidgets.QVBoxLayout(self)
for i in range(10):
w = ClickButton(str(i), self)
lay.addWidget(w)
if __name__ == '__main__':
import sys
app = QtWidgets.QApplication(sys.argv)
w = Widget()
w.show()
sys.exit(app.exec_())
Clicking a button crashes the process. What could be wrong?
from PySide import QtCore, QtGui
class button(QtGui.QPushButton):
def __init__(self, parent=None):
super(button, self).__init__(parent)
self.clicked.connect(self.click)
self.show()
def click(self):
self.emit(QtCore.SIGNAL('customSignal'), 'String Argument')
btn = button()
class label(QtGui.QLabel):
def __init__(self, parent=None):
super(label, self).__init__(parent)
self.connect(btn, QtCore.SIGNAL('customSignal'), self.Function)
self.show()
#QtCore.Slot(str)
def Function(self, arg=None):
print 'Function arg: %r'%arg
lbl = label()
No need for #QtCore.Slot decorator:
from PyQt4 import QtCore, QtGui
import sys
if __name__ == "__main__":
app = QtGui.QApplication(sys.argv)
class button(QtGui.QPushButton):
def __init__(self, parent=None):
super(button, self).__init__(parent)
self.clicked.connect(self.click)
self.show()
def click(self):
self.emit(QtCore.SIGNAL('customSignal'), 'String Argument')
btn = button()
class label(QtGui.QLabel):
def __init__(self, parent=None):
super(label, self).__init__(parent)
self.connect(btn, QtCore.SIGNAL('customSignal'), self.method)
self.show()
def method(self, arg=None):
print 'method arg: %r'%arg
lbl = label()
sys.exit(app.exec_())
==================
from PySide import QtCore, QtGui
def function(arg=None):
print 'function arg: %r'%arg
class button(QtGui.QPushButton):
def __init__(self, parent=None):
super(button, self).__init__(parent)
self.clicked.connect(self.click)
self.show()
def click(self):
self.emit(QtCore.SIGNAL('customSignal'), 'String Argument')
btn = button()
class label(QtGui.QLabel):
def __init__(self, parent=None):
super(label, self).__init__(parent)
self.connect(btn, QtCore.SIGNAL('customSignal'), function)
self.show()
lbl = label()
====
from PyQt4 import QtCore, QtGui
import datetime
def getDatetime():
return '%s'%datetime.datetime.strftime(datetime.datetime.now(), '%Y-%m-%d %H:%M:%S')
class CustomEvent(QtCore.QEvent):
_type = QtCore.QEvent.registerEventType()
def __init__(self, name=None):
QtCore.QEvent.__init__(self, CustomEvent._type)
class label(QtGui.QLabel):
def __init__(self, parent=None):
super(label, self).__init__(parent)
def customEvent(self, event):
print '....customEvent %s if event.type(): %s == CustomEvent._type: %s'%(event, event.type(), CustomEvent._type)
if event.type() == CustomEvent._type:
self.setText(getDatetime() )
class button(QtGui.QPushButton):
def __init__(self, parent=None):
super(button, self).__init__(parent)
self.clicked.connect(self.onClick)
self.show()
def onClick(self):
event = CustomEvent(name = 'Event Name')
QtCore.QCoreApplication.postEvent(lbl, event)
if __name__ == "__main__":
import sys
app = QtGui.QApplication(sys.argv)
btn = button()
btn.show()
lbl = label()
lbl.show()
sys.exit(app.exec_())