My PyQt5 script is skipping a line inside a function - python

I want to make a simple browser GUI for learning purposes with PyQt5. A function that I want is to have in the status bar a text "Online". If the user clicks somewhere else from the browser and the application loses focus, a message will appear in the status bar indicating that, and after a few seconds the browser will change the url to google.
If I run the following code everything works fine as expected, when app loses focus it navigates to google. However, the message "Application lost focus ..." doesn't appear in the statusbar. It simply skips that line. If I remove the seturl and time.sleep line, the script will change the text as expected.
Why is it skipping that line? (Line 55)
import sys
import time
from PyQt5.QtGui import QIcon, QFont
from PyQt5.QtCore import *
from PyQt5.QtWidgets import QApplication, QWidget, QPushButton, QMessageBox, QFrame ,QMainWindow, QLabel
from PyQt5.QtWebEngineWidgets import *
class VLine(QFrame):
# a simple VLine, like the one you get from designer
def __init__(self):
super(VLine, self).__init__()
self.setFrameShape(self.VLine|self.Sunken)
class MainWindow(QMainWindow):
def __init__(self):
super(MainWindow, self).__init__()
self.setFocus()
app.focusChanged.connect(self.on_focusChanged)
self.browser = QWebEngineView()
self.browser.setContextMenuPolicy(Qt.PreventContextMenu)
self.browser.setUrl(QUrl('http://stackoverflow.com'))
self.setCentralWidget(self.browser)
self.showMaximized()
self.date = QDate.currentDate()
font = QFont('Arial', 16, QFont.Bold)
self.statusBar().setFont(font)
timer = QTimer(self)
timer.timeout.connect(self.showTime)
timer.start(1000)
self.lbl1 = QLabel(self)
self.lbl1.setStyleSheet('border: 0; color: red;')
self.lbl1.setFont(font)
self.statusBar().reformat()
self.statusBar().setStyleSheet('border: 0; background-color: #FFF8DC;')
self.statusBar().setStyleSheet("QStatusBar::item {border: none;}")
self.statusBar().addPermanentWidget(VLine()) # <---
self.statusBar().addPermanentWidget(self.lbl1)
self.statusBar().addPermanentWidget(VLine())
def showTime(self):
current_time = QTime.currentTime()
label_time = current_time.toString('hh:mm:ss')
self.statusBar().showMessage('Time: ' + label_time + ' || Date: ' + self.date.toString('dd.MM.yyyy'))
def on_focusChanged(self):
if self.isActiveWindow() == False:
print(f"\nwindow is the active window: {self.isActiveWindow()}")
self.lbl1.setText('Application lost focus. Returning to Google in 5 seconds')
time.sleep(5)
self.browser.setUrl(QUrl('http://google.com'))
self.lbl1.setText('Online')
else:
print(f"window is the active window: {self.isActiveWindow()}")
self.lbl1.setText('Online')
app = QApplication(sys.argv)
QApplication.setApplicationName('Browser')
window = MainWindow()
app.exec_()

You are confusing how the focusChanged signal works: it emits a signal regarding the focus changes within the program.
What you need is to override the changeEvent of the window and intercept an ActivationChange event type.
class MainWindow(QMainWindow):
# ...
def changeEvent(self, event):
if event.type() == event.ActivationChange:
# ...
That said, NEVER put a blocking function within the main thread.
Remove the time.sleep and never think about using it again for this kind of things.
Add a function for that redirect, and create a QTimer that you can start when losing focus (and stop if regaining it again before the timeout).
class MainWindow(QMainWindow):
def __init__(self):
# ...
self.focusLostTimer = QTimer(
interval=5000, singleShot=True, timeout=self.focusRedirect)
def focusRedirect(self):
self.browser.setUrl(QUrl('http://google.com'))
def changeEvent(self, event):
if event.type() == event.ActivationChange:
if not self.isActiveWindow():
self.focusLostTimer.start()
else:
self.focusLostTimer.stop()

Related

Open popup notification on the same monitor where the mainwindow is in python an pyqt5

In my QMainWindow i have a button which opens a new QDialog in the bottom right monitorcorner with a successmessage when i click it.
Now, if i move the QMainWindow to another monitor (i have 3 monitor) and click the button the successmessage popup appears in the monitor where the QMainWindow was opened. What i want is that the popup message appears in the monitor where my QMainWindow actually is. So if i move the QMainWindow to Monitor 1 and click the button, the successpopup should opens in monitor 1. If the QMainWindow is in monitor 2, the successpopup should open in monitor 2 an same for monitor 3.
with
screenNumber = QDesktopWidget().screenNumber(self)
i can read the screennumber where the mainwindow is. and this works fine. Evertime i click the button i read out the screennumber. But i don't found a way, to set the screennumber to my notification.
Any ideas?
Edit:
maybe it helps if i show my notify class
notes.py
from UIs.UI_notify import Ui_Notification
from PyQt5.QtWidgets import QDialog, QApplication, QDesktopWidget
from PyQt5 import QtCore
from PyQt5.QtCore import QRect, QPropertyAnimation, QTimer
import sys
class icon():
checked = "check-circle"
alert = "times-circle"
question = "question-circle"
class notify(QDialog, Ui_Notification):
def __init__(self, parent=None):
super(notify,self).__init__(parent)
self.setupUi(self)
self.setWindowFlag(QtCore.Qt.WindowType.FramelessWindowHint)
self.setAttribute(QtCore.Qt.WidgetAttribute.WA_TranslucentBackground)
## Some helping stuff
############################################################
parent_sSize = QDesktopWidget().screenGeometry(parent)
parent_screenNumber = QDesktopWidget().screenNumber(parent)
sSize = QDesktopWidget().screenGeometry()
screenNumber = QDesktopWidget().screenNumber()
print("notification ScreenNumber = " + str(screenNumber))
print(sSize.width())
print(sSize.height())
print("Parents ScreenNumber = " + str(parent_screenNumber))
print(parent_sSize.width())
print(parent_sSize.height())
self.Note_Exit.clicked.connect(self.close)
## ScreenSize from parent
############################################################
self.hidedPos = QRect(parent_sSize.width()-self.width()-10,
parent_sSize.height()-self.height()+200,
self.frameGeometry().width(),
self.frameGeometry().height())
self.showPos = QRect(parent_sSize.width()-self.width()-10,
parent_sSize.height()-self.height()-50,
self.frameGeometry().width(),
self.frameGeometry().height())
def setNote(self, icon=icon.checked, headline="Headline", text="Text"):
self.icon = icon
self.headline = headline
self.text = text
self.noty_Label_Icon.setText(self.icon)
self.noty_Label_Headline.setText(self.headline)
self.noty_Label_Text.setText(self.text)
self.setGeometry(self.hidedPos)
self.anim = QPropertyAnimation(self,b"geometry")
self.anim.setDuration(700)
self.anim.setEasingCurve(QtCore.QEasingCurve.OutBack)
self.anim.setEndValue(self.showPos)
self.anim.start()
self.notyTimer = QTimer()
self.notyTimer.singleShot(4000,self.hideNote)
def hideNote(self):
self.anim = QPropertyAnimation(self,b"geometry")
self.anim.setDuration(700)
self.anim.setEasingCurve(QtCore.QEasingCurve.InOutBack)
self.anim.setEndValue(self.hidedPos)
self.anim.start()
self.anim.finished.connect(self.close)
if __name__ == "__main__":
notes = QApplication(sys.argv)
dialog = notify()
dialog.show()
sys.exit(notes.exec())
You cannot use the size of the widget during its construction, as at that moment it has a default size (640x480 for top level widgets, 100x30 for widgets created with a parent, including dialogs): the only reliable option is to use the sizeHint() or ensure that the layout has been properly activated with adjustSize().
Then, you don't need the screen to get the target position, as the parent geometry will suffice, but you do need it for the start position, otherwise the dialog will "pop up" at an arbitrary point below the window. Note that QDesktopWidget is considered obsolete, and you should use QScreen instead.
Finally, since you might want to reuse the notification, the start position should be set when the popup is actually being shown, not before. The same goes for the position when hiding (in case the notification could be moved).
class Notify(QDialog, Ui_Notification):
def __init__(self, parent):
super().__init__(parent)
self.setupUi(self)
self.setWindowFlag(QtCore.Qt.WindowType.FramelessWindowHint)
self.setAttribute(QtCore.Qt.WA_TranslucentBackground)
self.showAnim = QPropertyAnimation(self, b'geometry')
self.showAnim.setDuration(700)
self.showAnim.setEasingCurve(QtCore.QEasingCurve.OutBack)
self.hideAnim = QPropertyAnimation(self, b'geometry')
self.hideAnim.setDuration(700)
self.hideAnim.setEasingCurve(QtCore.QEasingCurve.InOutBack)
self.hideTimer = QTimer(self, singleShot=True)
self.hideTimer.setInterval(4000)
self.hideTimer.timeout.connect(self.hideNote)
self.showAnim.finished.connect(self.hideTimer.start)
self.hideAnim.finished.connect(self.close)
def setNote(self, icon=icon.checked, headline="Headline", text="Text"):
self.icon = icon
self.headline = headline
self.text = text
self.noty_Label_Icon.setText(self.icon)
self.noty_Label_Headline.setText(self.headline)
self.noty_Label_Text.setText(self.text)
self.adjustSize() # important!
endRect = self.rect()
center = self.parent().geometry().center()
endRect.moveCenter(center)
screen = QApplication.screenAt(center)
startRect = QRect(endRect)
startRect.moveTop(screen.geometry().bottom())
self.setGeometry(startRect)
self.showAnim.setStartValue(startRect)
self.showAnim.setEndValue(endRect)
self.showAnim.start()
self.show()
def hideNote(self):
rect = self.geometry()
self.hideAnim.setStartValue(rect)
screen = QApplication.screenAt(rect.center())
rect.moveTop(screen.geometry().bottom())
self.hideAnim.setEndValue(rect)
self.hideAnim.start()
if __name__ == "__main__":
notes = QApplication(sys.argv)
notes.setStyle('fusion')
w = QMainWindow()
b = QPushButton('click!')
w.setCentralWidget(b)
w.show()
notify = Notify(w)
b.clicked.connect(lambda: notify.setNote())
sys.exit(notes.exec())
Be aware that if you're going to create the popup every time, you should also set the WA_DeleteOnClose attribute in order to destroy it when closed, otherwise it will be kept in memory.
Note: QTimer.singleShot() is a static function, creating an instance of QTimer to use it is pointless, as that instance won't be used and a new QTimer would be created anyway.
Thank you.
In the meantime i found a solution which works for me.
Look a little dirty but works.
could you tell me, whats the difference between my code an yours?
Why should i use your code, except the fact that you are a better programmer ;-)
I set the WA_DeleteOnClose Attribute.
Good to know that. Thanks
notes.py
from UIs.UI_notify import Ui_Notification
from PyQt5.QtWidgets import QDialog, QApplication
from PyQt5 import QtCore
from PyQt5.QtCore import QRect, QPropertyAnimation, QTimer
import sys
class icon():
checked = "check-circle"
alert = "times-circle"
question = "question-circle"
clock = "clock"
class notify(QDialog, Ui_Notification):
def __init__(self, parent=None):
super(notify,self).__init__(parent)
self.setupUi(self)
self.setWindowFlag(QtCore.Qt.WindowType.FramelessWindowHint)
self.setAttribute(QtCore.Qt.WidgetAttribute.WA_TranslucentBackground)
self.setAttribute(QtCore.Qt.WidgetAttribute.WA_DeleteOnClose)
self.setWindowModality(QtCore.Qt.NonModal)
self.Note_Exit.clicked.connect(self.close)
self.parent_h = self.parent().geometry().height()
self.parent_w = self.parent().geometry().width()
self.parent_x = self.parent().geometry().x()
self.parent_y = self.parent().geometry().y()
self.dialog_w = self.width()
self.dialog_h = self.height()
self.setGeometry(self.parent_x+self.parent_w-self.dialog_w-10, self.parent_y+self.parent_h-self.dialog_h+120, self.dialog_w, self.dialog_h)
## ScreenSize from parent
############################################################
def setNote(self, icon=icon.checked, headline="Headline", text="Text"):
self.icon = icon
self.headline = headline
self.text = text
self.noty_Label_Icon.setText(self.icon)
self.noty_Label_Headline.setText(self.headline)
self.noty_Label_Text.setText(self.text)
self.anim = QPropertyAnimation(self,b"geometry")
self.anim.setDuration(700)
self.anim.setEasingCurve(QtCore.QEasingCurve.OutBack)
self.anim.setEndValue(QRect(self.parent_x+self.parent_w-self.dialog_w-10, self.parent_y+self.parent_h-self.dialog_h-20, self.dialog_w, self.dialog_h))
self.anim.start()
self.notyTimer = QTimer()
self.notyTimer.singleShot(4000,self.hideNote)
def hideNote(self):
self.anim = QPropertyAnimation(self,b"geometry")
self.anim.setDuration(700)
self.anim.setEasingCurve(QtCore.QEasingCurve.InOutBack)
self.anim.setEndValue(QRect(self.parent_x+self.parent_w-self.dialog_w-10, self.parent_y+self.parent_h-self.dialog_h+120, self.dialog_w, self.dialog_h))
self.anim.start()
self.anim.finished.connect(self.close)
if __name__ == "__main__":
notes = QApplication(sys.argv)
dialog = notify()
dialog.show()
sys.exit(notes.exec())

PyQt5 QTabWidget showing currentWidget() "NoneType"

I'm building a simple browser with python, PyQt5 QWebEnjineView.
I want to make the reload button to be hidden when the page is loading and "stop loading" button visible,
When loading is finished, then reload button will be visible again and "stop loading" button will be hidden.
My QWebEnjineView is in a method called add_new_tab and I've defined QTabWidget as self.tabs in the init method.
import os
import sys
from PyQt5 import QtGui
from PyQt5 import QtCore
from PyQt5.QtGui import *
from PyQt5.QtCore import *
from PyQt5.QtWidgets import *
from PyQt5.QtWebEngineWidgets import QWebEngineView
class mainWindow(QMainWindow):
def __init__(self, *args, **kwargs):
super(mainWindow, self).__init__()
# create tabs
self.tabs = QTabWidget()
self.tabs.tabBarDoubleClicked.connect(self.tab_open_doubleclick)
self.tabs.setTabsClosable(True)
self.tabs.tabCloseRequested.connect(self.close_current_tab)
self.tabs.currentWidget().loadProgress.connect(self.loadProgressHandler)
self.tabs.currentWidget().loadFinished.connect(self.loadFinishedHandler)
self.setCentralWidget(self.tabs)
# self.setCentralWidget(self.browser)
self.showMaximized()
# nav bar
self.navbar = QToolBar()
self.navbar.setMovable(False)
self.addToolBar(self.navbar)
# Refresh button
self.reload_butn = QPushButton(self, text="Reload")
self.reload_butn.clicked.connect(self.reload_tab)
# Set reload button visible
self.reload_butn.setHidden(False)
# Stop button
self.stop_btn = QPushButton(self, text="Stop")
self.stop_btn.clicked.connect(self.stop_loading_tab)
self.stop_btn.setHidden(True)
# Set stop_butn hidden initially
self.stop_btn.setHidden(True)
# Add Refresh and Stop button
self.navbar.addWidget(self.stop_btn)
self.navbar.addWidget(self.reload_butn)
# Add Address bar
self.url_bar = QLineEdit()
self.url_bar.returnPressed.connect(self.navigate_to_url)
self.navbar.addWidget(self.url_bar)
# on startup
self.add_new_tab(QUrl("https://www.google.com/"), "Homepage")
self.show()
#QtCore.pyqtSlot(int)
def loadProgressHandler(self, prog):
self.stop_btn.setHidden(False) # When any page is loading, then stop_butn will visible
self.reload_butn.setHidden(True) # When any page is loading, then reload_butn will hidde
#QtCore.pyqtSlot()
def loadFinishedHandler(self):
self.reload_butn.setHidden(False) # When loading is finished, then reload_butn will be visible again for the user
self.stop_btn.setHidden(True) # When load finished, stop button will be hidden
# reload tab
def reload_tab(self):
self.tabs.currentWidget().reload()
def stop_loading_tab(self):
self.tabs.currentWidget().stop()
def close_current_tab(self, i):
if self.tabs.count() < 2 :
return
self.tabs.removeTab(i)
# stop load current tab
def stop_loading_tab(self):
self.tabs.currentWidget().stop()
# doubleclick on empty space for new tab
def tab_open_doubleclick(self, i):
if i == -1: # No tab under the click
self.add_new_tab(QUrl("http://www.google.com/"), label="New tab")
# function to add new tab
def add_new_tab(self, qurl=None, label="Blank"):
if qurl is None:
qurl = QUrl('https://www.google.com/')
browser = QWebEngineView()
browser.setUrl(qurl)
i = self.tabs.addTab(browser, label)
self.tabs.setCurrentIndex(i)
def navigate_to_url(self):
self.tabs.currentWidget().setUrl(QUrl(self.url_bar.text()))
app = QApplication(sys.argv)
app.setApplicationName("browser")
window = mainWindow()
app.exec_()
I have some button for reload, back, home etc. where I called self.tabs.currentWidget().reload() for example in the reload method,
But when I'm adding self.tabs.currentWidget().loadProgress.connect(self.loadProgressHandler)
for the operation, then It's giving me a error
self.tabs.currentWidget().loadProgress.connect(self.loadProgressHandler)
AttributeError: 'NoneType' object has no attribute 'loadProgress'
Can anyone tell me why is it showing that the self.tabs.currentWidget() is NoneType?
Is there a way to fix it? Ask me if you need more details
Thank you!
The cause of the error is:
self.tabs.currentWidget().loadProgress.connect(self.loadProgressHandler)
self.tabs.currentWidget().loadFinished.connect(self.loadFinishedHandler)
Where the OP is assuming that the connection will occur with all the pages, and that is incorrect since it will only occur with the current widget which in that case is None causing the error.
In this case the solution is to connect each QWebEngineView created and check in the slots if the sender() matches the currentWidget().
remove
self.tabs.currentWidget().loadProgress.connect(self.loadProgressHandler)
self.tabs.currentWidget().loadFinished.connect(self.loadFinishedHandler)
add connection:
def add_new_tab(self, qurl=None, label="Blank"):
if qurl is None:
qurl = QUrl('https://www.google.com/')
browser = QWebEngineView()
browser.loadProgress.connect(self.loadProgressHandler)
browser.loadFinished.connect(self.loadFinishedHandler)
i = self.tabs.addTab(browser, label)
self.tabs.setCurrentIndex(i)
browser.load(qurl)
Validate:
#QtCore.pyqtSlot(int)
def loadProgressHandler(self, prog):
if self.tabs.currentWidget() is not self.sender():
return
self.stop_btn.show()
self.reload_butn.hide()
#QtCore.pyqtSlot()
def loadFinishedHandler(self):
if self.tabs.currentWidget() is not self.sender():
return
self.reload_butn.show()
self.stop_btn.hide()
Update:
There are the following errors:
The visibility of the widgets added to the QToolBar are managed using the associated QActions.
Instead of managing 2 slots associated with the progress and completion of loading, only one of them should be used since, for example, the associated slot is also called when it is loaded at 100% so it could be hidden since it can be invoked together with finished.
It is better to verify that the variables that can be None to avoid exceptions.
Considering the above, the solution is:
import sys
from PyQt5.QtCore import pyqtSlot, QUrl
from PyQt5.QtWidgets import (
QApplication,
QLineEdit,
QMainWindow,
QPushButton,
QTabWidget,
QToolBar,
)
from PyQt5.QtWebEngineWidgets import QWebEngineView
class mainWindow(QMainWindow):
def __init__(self, parent=None):
super(mainWindow, self).__init__(parent)
self.tabs = QTabWidget(tabsClosable=True)
self.tabs.tabBarDoubleClicked.connect(self.tab_open_doubleclick)
self.tabs.tabCloseRequested.connect(self.close_current_tab)
self.navbar = QToolBar(movable=True)
self.addToolBar(self.navbar)
self.reload_butn = QPushButton(self, text="Reload")
self.reload_butn.clicked.connect(self.reload_tab)
self.stop_btn = QPushButton(self, text="Stop")
self.stop_btn.clicked.connect(self.stop_loading_tab)
self.url_bar = QLineEdit()
self.url_bar.returnPressed.connect(self.navigate_to_url)
self.stop_action = self.navbar.addWidget(self.stop_btn)
self.reload_action = self.navbar.addWidget(self.reload_butn)
self.navbar.addWidget(self.url_bar)
self.stop_action.setVisible(False)
self.add_new_tab(QUrl("https://www.google.com/"), "Homepage")
self.setCentralWidget(self.tabs)
self.showMaximized()
#pyqtSlot(int)
def loadProgressHandler(self, prog):
if self.tabs.currentWidget() is not self.sender():
return
loading = prog < 100
self.stop_action.setVisible(loading)
self.reload_action.setVisible(not loading)
def reload_tab(self):
self.tabs.currentWidget().reload()
def stop_loading_tab(self):
self.tabs.currentWidget().stop()
def close_current_tab(self, i):
if self.tabs.count() < 2:
return
self.tabs.removeTab(i)
def stop_loading_tab(self):
if self.tabs.currentWidget() is None:
return
self.tabs.currentWidget().stop()
def tab_open_doubleclick(self, i):
if i == -1:
self.add_new_tab(QUrl("http://www.google.com/"), label="New tab")
def add_new_tab(self, qurl=None, label="Blank"):
if qurl is None:
qurl = QUrl("https://www.google.com/")
browser = QWebEngineView()
browser.loadProgress.connect(self.loadProgressHandler)
i = self.tabs.addTab(browser, label)
self.tabs.setCurrentIndex(i)
browser.load(qurl)
def navigate_to_url(self):
if self.tabs.currentWidget() is None:
return
self.tabs.currentWidget().load(QUrl.fromString(self.url_bar.text()))
def main():
app = QApplication(sys.argv)
app.setApplicationName("browser")
window = mainWindow()
app.exec_()
if __name__ == "__main__":
main()

How do I draw on a Qlabel with QPainter when multithreading with QThreadpool?

Please excuse me if my description isn't perfect, I'm still pretty new at PyQt and also Python in general. If you have recommendations on how to improve the question, please let me know.
I'm trying to draw on a Pixmap-QLabel, which is part of a QMainWindow, with QPainter. The QPainter is called in a loop, because the drawing is updated after a fixed duration. Drawing on the Pixmap works as intended, the problem I have is that the label always opens in a new window, instead of being placed on the QLabel inside the original QMainWindow.
I suspect that the reason for that is that I'm calling the QPainter from a Worker-class-object which is created by the QThreadpool-object. If I call the QPainter from inside the initialization of the GUI, the Pixmap-label is created as part of the QMainWindow as intended. Unfortunately the multithreading is necessary so the GUI stays responsive while the QLabel is updating.
The GUI itself is created with QtCreator, and simply loaded into the script.
Here's my code:
import os
import sys
import time
from PyQt5 import QtWidgets, QtCore, uic
from PyQt5.QtWidgets import QLabel, QPushButton, QMainWindow
from PyQt5.QtGui import QPixmap, QPainter, QPen, QPaintEvent
from PyQt5.QtCore import *
class Ui(QMainWindow):
def __init__(self):
super(Ui, self).__init__()
self.counter = 0
# load ui which can be designed with Qt Creator
uic.loadUi("ui/paintEvent_Loop.ui", self)
# find the QLabel where the picture should be placed
self.pixmap_label = self.findChild(QtWidgets.QLabel, "pixmap_label")
# creating the pixmap-label here works as intended
'''self.draw_label = PixmapLabel(self.pixmap_label)
self.draw_label.setGeometry(130, 50, 911, 512)
self.draw_label.show()'''
self.label = self.findChild(QLabel, "label")
# find the button with the name "cancel_button"
self.cancel_button = self.findChild(QtWidgets.QPushButton, "cancel_button")
self.cancel_button.clicked.connect(self.close_application)
# find the start_button button
self.start_button = self.findChild(QtWidgets.QPushButton, "start_button")
self.start_button.clicked.connect(self.start_loop)
self.pause_cont_button = self.findChild(QPushButton, "pause_cont_button")
self.pause_cont_button.clicked.connect(self.toggle_pause_continue)
self.pause_cont_button.hide()
# create the QThreadPool object to manage multiple threads
self.threadpool = QThreadPool()
print("Multithreading with maximum %d threads" % self.threadpool.maxThreadCount())
self.run_loop = True
# show application
self.show()
def close_application(self):
app.quit()
def toggle_pause_continue(self):
"""
changes the value of boolean run_loop to pause and continue the loop through the samples in the chosen scene
:return:
"""
if self.run_loop:
self.run_loop = False
else:
self.run_loop = True
def start_loop(self):
# hide start_button and show pause_cont_button
self.start_button.hide()
self.pause_cont_button.show()
self.pause_cont_button.setCheckable(True)
# start one further thread managed by threadpool
worker = Worker()
self.threadpool.start(worker)
class PixmapLabel(QLabel):
def __init__(self, parent=None):
super(PixmapLabel, self).__init__(parent=parent)
def paintEvent(self, a0: QPaintEvent) -> None:
# initiate QPainter instance
painter = QPainter(window.draw_label)
# open image
picture = QPixmap(os.getcwd() + '/test-image.png')
myPicturePixmap = picture.scaled(self.size(), QtCore.Qt.KeepAspectRatio)
self.setPixmap(myPicturePixmap)
# draw red box on it
painter.drawPixmap(self.rect(), myPicturePixmap)
pen = QPen(Qt.red, 3)
painter.setPen(pen)
painter.drawRect(10, 10, 100, 100)
class Worker(QRunnable):
# worker thread
def __init__(self):
super().__init__()
#pyqtSlot()
def run(self):
print("Thread start")
for self.i in range(0, 50):
# create pixmap_label with drawings
# FIXME: make pixmap-label part of original GUI
window.draw_label = PixmapLabel(window.pixmap_label)
window.draw_label.setGeometry(130, 50, 911, 512)
window.draw_label.show()
window.label.setText(str(self.i))
while window.run_loop == False:
time.sleep(0.05)
# show image for 0.5 seconds, then update image
time.sleep(0.5)
window.draw_label.destroy()
time.sleep(0.05)
# print in terminal to know that we are finished
print("Thread complete")
if __name__ == "__main__":
app = QtWidgets.QApplication(sys.argv)
window = Ui()
app.exec_()
The image I'm using:

PyQt: signal emitted twice when calculations are too long

I use two widgets: a QSpinBox and a QLineEdit. valueChanged slot of the QSpinBox widget is connected to the update function. This function consist of a time-consuming processing (a loop with calculations or a time.sleep() call) and a QLineEdit.setText() call. At the beginning, i thought it worked as expected but I noticed that the signal seems to be emitted twice when the calculations takes a long time.
Bellow is the code:
import time
from PyQt5.QtWidgets import QWidget, QSpinBox, QVBoxLayout, QLineEdit
class Window(QWidget):
def __init__(self):
# parent constructor
super().__init__()
# widgets
self.spin_box = QSpinBox()
self.line_edit = QLineEdit()
# layout
v_layout = QVBoxLayout()
v_layout.addWidget(self.spin_box)
v_layout.addWidget(self.line_edit)
# signals-slot connections
self.spin_box.valueChanged.connect(self.update)
#
self.setLayout(v_layout)
self.show()
def update(self, param_value):
print('update')
# time-consuming part
time.sleep(0.5) # -> double increment
#time.sleep(0.4) # -> works normally!
self.line_edit.setText(str(param_value))
if __name__ == '__main__':
from PyQt5.QtWidgets import QApplication
import sys
app = QApplication(sys.argv)
win = Window()
sys.exit(app.exec_())
Another version of update:
# alternative version, calculations in a loop instead of time.sleep()
# -> same behaviour
def update2(self, param_value):
print('update2')
for i in range(2000000): # -> double increment
x = i**0.5 * i**0.2
#for i in range(200000): # -> works normally!
# x = i**0.5 * i**0.2
self.line_edit.setText(str(param_value))
There is no real mystery here. If you click a spin-box button, the value will increase by a single step. But if you press and hold down the button, it will increase the values continually. In order to tell the difference between a click and a press/hold, a timer is used. Presumably, the threshold is around half a second. So if you insert a small additional delay, a click may be interpreted as a short press/hold, and so the spin-box will increment by two steps instead of one.
UPDATE:
One way to work around this behaviour is by doing the processing in a worker thread, so that the delay is eliminated. The main problem with this is avoiding too much lag between spin-box value changes and line-edit updates. If you press and hold the spin-box button, a large number of signal events could be queued by the worker thread. A simplistic approach would wait until the spin-box button was released before handling all those queued signals - but that would result in a long delay whilst each value was processed separately. A better approach is to compress the events, so that only the most recent signal is handled. This will still be somewhat laggy, but if the processing time is not too long, it should result in acceptable behaviour.
Here is a demo that implements this approach:
import sys, time
from PyQt5.QtWidgets import (
QApplication, QWidget, QSpinBox, QVBoxLayout, QLineEdit,
)
from PyQt5.QtCore import (
pyqtSignal, pyqtSlot, Qt, QObject, QThread, QMetaObject,
)
class Worker(QObject):
valueUpdated = pyqtSignal(int)
def __init__(self, func):
super().__init__()
self._value = None
self._invoked = False
self._func = func
#pyqtSlot(int)
def handleValueChanged(self, value):
self._value = value
if not self._invoked:
self._invoked = True
QMetaObject.invokeMethod(self, '_process', Qt.QueuedConnection)
print('invoked')
else:
print('received:', value)
#pyqtSlot()
def _process(self):
self._invoked = False
self.valueUpdated.emit(self._func(self._value))
class Window(QWidget):
def __init__(self):
super().__init__()
self.spin_box = QSpinBox()
self.line_edit = QLineEdit()
v_layout = QVBoxLayout()
v_layout.addWidget(self.spin_box)
v_layout.addWidget(self.line_edit)
self.setLayout(v_layout)
self.thread = QThread(self)
self.worker = Worker(self.process)
self.worker.moveToThread(self.thread)
self.worker.valueUpdated.connect(self.update)
self.spin_box.valueChanged.connect(self.worker.handleValueChanged)
self.thread.start()
self.show()
def process(self, value):
time.sleep(0.5)
return value
def update(self, param_value):
self.line_edit.setText(str(param_value))
if __name__ == '__main__':
app = QApplication(sys.argv)
win = Window()
sys.exit(app.exec_())

How to customize QPushButton to only popup menu when clicked around the arrow?

I want to add a popup menu to QPushButton, but only popup it when you click near the arrow, if you click other area on the button, it calls the slot connected in main UI.
I know there is QToolButton, and you can set its ToolButtonPopupMode to MenuButtonPopup, but for some reason it looks different than then rest of the button on my UI, I assume I could somehow modify the style of it to make it look exactly like QPushButton, anyway in the end I decided to subclass QPushButton instead.
The problems in the following code are:
1. How do I get the rect of the arrow, maybe show a dashed rect around the arrow, I thought the "popup menu hotspot" area should be a little bit bigger than the arrow. right now I hardcoded 20px, but I think it should be retrieved from QStyle?
[solved] How to make the button look "pressed" when clicked not near the arrow, right now its look does not change, I guess it's because I did not call base class MousePressEvent, because I don't want the menu to popup when clicked elsewhere.
How to move the position of the arrow, in my applicaton it is too close to the right edge, how can I move it to the left a little bit?
code:
from PyQt4 import QtGui, QtCore
import sys
class MyButton(QtGui.QPushButton):
def __init__(self, parent=None):
super(MyButton, self).__init__(parent)
def mousePressEvent(self, event):
if event.type() == QtCore.QEvent.MouseButtonPress:
# figure out press location
pos = event.pos
topRight = self.rect().topRight()
bottomRight = self.rect().bottomRight()
frameWidth = self.style().pixelMetric(QtGui.QStyle.PM_DefaultFrameWidth)
print topRight, bottomRight, frameWidth
# get the rect from QStyle instead of hardcode numbers here
arrowTopLeft = QtCore.QPoint(topRight.x()-20, topRight.y())
arrowRect = QtCore.QRect(arrowTopLeft, bottomRight)
if arrowRect.contains(event.pos()):
print 'clicked near arrow'
# event.accept()
QtGui.QPushButton.mousePressEvent(self, event)
else:
print 'clicked outside'
# call the slot connected, without popup the menu
# the following code now does not make
# the button pressed
self.clicked.emit(True)
event.accept()
class Main(QtGui.QDialog):
def __init__(self, parent=None):
super(Main, self).__init__(parent)
layout = QtGui.QVBoxLayout()
pushbutton = MyButton('Popup Button')
layout.addWidget(pushbutton)
menu = QtGui.QMenu()
menu.addAction('This is Action 1', self.Action1)
menu.addAction('This is Action 2', self.Action2)
pushbutton.setMenu(menu)
self.setLayout(layout)
pushbutton.clicked.connect(self.button_press)
def button_press(self):
print 'You pressed button'
def Action1(self):
print 'You selected Action 1'
def Action2(self):
print 'You selected Action 2'
if __name__ == '__main__':
app = QtGui.QApplication(sys.argv)
main = Main()
main.show()
app.exec_()
edit:
it seems this will stop the menu from poping up if clicked on the left side of the button
else:
print 'clicked outside'
self.blockSignals(True)
QtGui.QPushButton.mousePressEvent(self, event)
self.blockSignals(False)
Have you thought on using a QComboBox?
Or maybe two buttons next to each other one for appearance only, and the other that calls your context?
Would work to use mask on your button through pixmap.
You also could make some use of setStyleSheet("") can make some use of these attributes.
Here is a little example:
import sys
from PyQt5.QtCore import Qt
from PyQt5.QtWidgets import QApplication
from PyQt5.QtWidgets import QHBoxLayout
from PyQt5.QtWidgets import QPushButton
from PyQt5.QtWidgets import QScrollArea
from PyQt5.QtWidgets import QVBoxLayout
from PyQt5.QtWidgets import QWidget
class WPopUpButton(QWidget):
"""WPopUpButton is a personalized QPushButton."""
w_container = None
v_layout_container = None
v_scroll_area = None
v_layout_preview = None
def __init__(self):
"""Init UI."""
super(WPopUpButton, self).__init__()
self.init_ui()
def init_ui(self):
"""Init all ui object requirements."""
self.button_that_do_nothing = QPushButton("Popup Button")
self.button_that_do_nothing.setStyleSheet("""
border: 0px;
background: gray;
""")
self.button_that_do_something = QPushButton("->")
#you can also set icon, to make it look better :D
self.button_that_do_something.setStyleSheet("""
border: 0px;
background: gray;
""")
self.layout = QHBoxLayout()
self.layout.setSpacing(0)
self.layout.setContentsMargins(0,0,0,0)
self.layout.addWidget(self.button_that_do_nothing)
self.layout.addWidget(self.button_that_do_something)
self.setLayout(self.layout)
self.create_connections()
def create_connections(self):
self.button_that_do_something.pressed.connect(self.btn_smtg_pressed)
self.button_that_do_something.released.connect(self.btn_smtg_released)
def btn_smtg_pressed(self):
self.button_that_do_something.setStyleSheet("""
border: 0px;
background: blue;
""")
def btn_smtg_released(self):
self.button_that_do_something.setStyleSheet("""
border: 0px;
background: gray;
""")
# HERE YOU DO WHAT YOU NEED
# FOR EXAMPLE CALL YOUR CONTEXT WHATEVER :D
def run():
app = QApplication(sys.argv)
GUI = WPopUpButton()
GUI.show()
sys.exit(app.exec_())
run()
By the way I'm using Pyqt5, you just gotta change your imports ")
Here's another option that may partially answer your question.
Instead of using the default menu, you can combine CustomContextMenu and custom arrow created by either QLabel and/or .png images.
setContentsMargins in the code will allow a much more flexible layout.
sample image
import os
from PyQt5.QtWidgets import (
QDialog,
QPushButton,
QApplication,
QVBoxLayout,
QMenu,
QStyle,
QHBoxLayout,
QLabel,
)
from PyQt5.QtCore import (
QEvent,
QPoint,
QRect,
Qt,
QSize,
)
from PyQt5.QtGui import (
QIcon,
QMouseEvent,
)
import sys
import functools
import copy
class MyButton(QPushButton):
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
self.clicked_near_arrow = None
# set icon by letter
self.label_icon = QLabel(" ▼ ")
self.label_icon.setAttribute(Qt.WA_TranslucentBackground)
self.label_icon.setAttribute(Qt.WA_TransparentForMouseEvents)
icon_size = QSize(19, 19)
# set icon by picture
self.pixmap_default = QIcon("default_button.png").pixmap(icon_size) # prepare images if necessary
self.pixmap_presssed = QIcon("pressed_button.png").pixmap(icon_size) # prepare images if necessary
self.pic_icon = QLabel()
self.pic_icon.setAttribute(Qt.WA_TranslucentBackground)
self.pic_icon.setAttribute(Qt.WA_TransparentForMouseEvents)
self.pic_icon.setPixmap(self.pixmap_default)
# layout
lay = QHBoxLayout(self)
lay.setContentsMargins(0, 0, 6, 3)
lay.setSpacing(0)
lay.addStretch(1)
lay.addWidget(self.pic_icon)
lay.addWidget(self.label_icon)
def set_icon(self, pressed):
if pressed:
self.label_icon.setStyleSheet("QLabel{color:white}")
self.pic_icon.setPixmap(self.pixmap_presssed)
else:
self.label_icon.setStyleSheet("QLabel{color:black}")
self.pic_icon.setPixmap(self.pixmap_default)
def mousePressEvent(self, event):
if event.type() == QEvent.MouseButtonPress:
self.set_icon(pressed=True)
# figure out press location
topRight = self.rect().topRight()
bottomRight = self.rect().bottomRight()
# get the rect from QStyle instead of hardcode numbers here
arrowTopLeft = QPoint(topRight.x()-19, topRight.y())
arrowRect = QRect(arrowTopLeft, bottomRight)
if arrowRect.contains(event.pos()):
self.clicked_near_arrow = True
self.blockSignals(True)
QPushButton.mousePressEvent(self, event)
self.blockSignals(False)
print('clicked near arrow')
self.open_context_menu()
else:
self.clicked_near_arrow = False
QPushButton.mousePressEvent(self, event)
def mouseMoveEvent(self, event):
if self.rect().contains(event.pos()):
self.set_icon(pressed=True)
else:
self.set_icon(pressed=False)
QPushButton.mouseMoveEvent(self, event)
def mouseReleaseEvent(self, event):
self.set_icon(pressed=False)
if self.clicked_near_arrow:
self.blockSignals(True)
QPushButton.mouseReleaseEvent(self, event)
self.blockSignals(False)
else:
QPushButton.mouseReleaseEvent(self, event)
def setMenu(self, menu):
self.menu = menu
self.setContextMenuPolicy(Qt.CustomContextMenu)
self.customContextMenuRequested.connect(self.open_context_menu)
# ContextMenueのlauncher
def open_context_menu(self, point=None):
point = QPoint(7, 23)
self.menu.exec_(self.mapToGlobal(point))
event = QMouseEvent(QEvent.MouseButtonRelease, QPoint(10, 10), Qt.LeftButton, Qt.LeftButton, Qt.NoModifier)
self.mouseReleaseEvent(event)
class Main(QDialog):
def __init__(self, parent=None):
super(Main, self).__init__(parent)
menu = QMenu()
menu.addAction('This is Action 1', self.Action1)
menu.addAction('This is Action 2', self.Action2)
pushbutton = MyButton('Popup Button')
pushbutton.setMenu(menu)
layout = QVBoxLayout()
layout.addWidget(pushbutton)
self.setLayout(layout)
# event connect
pushbutton.setAutoDefault(False)
pushbutton.clicked.connect(self.button_press)
def button_press(self):
print('You pressed button')
def Action1(self):
print('You selected Action 1')
def Action2(self):
print('You selected Action 2')
if __name__ == '__main__':
app = QApplication(sys.argv)
main = Main()
main.show()
app.exec_()

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