Closing QWidget window - python

I am using following code to close Qwidget window automatically after some period of time
class ErrorWindow2(QtGui.QWidget):
def __init__( self ):
QtGui.QWidget.__init__( self, None, QtCore.Qt.WindowStaysOnTopHint)
msgBox = QMessageBox(self)
msgBox.move (500,500)
msgBox.setIcon(QMessageBox.Critical)
msgBox.setText("Test 2")
msgBox.setWindowTitle("ERROR")
msgBox.setStandardButtons(QMessageBox.Ok)
self.errWin2Timer = QtCore.QTimer()
self.errWin2Timer.timeout.connect(self.closeBox)
self.errWin2Timer.setSingleShot(True)
self.errWin2Timer.start(10000)
ret = msgBox.exec_()
if ret == QtGui.QMessageBox.Ok:
return
else:
return
def closeBox(self):
self.close()
def closeEvent(self, event):
logger.debug("Reached Error window 1 close event")
if self.errWin2:
self.errWin2.stop()
self.errWin2.deleteLater()
event.accept()
But the problem is that self.close doesn't work. What is the best possible way to close the window automatically after some period of time?

The problem is that when you put ret = msgBox.exec_() before the constructor finishes executing, the window object has not finished being built, so there is nothing to close, so when the dialog is closed the window that was just opened will be displayed. I finish building. The idea is to finish building the window and then call ret = msgBox.exec_() and for that we will use a QTimer.singleShot().
On the other hand, the closeEvent method is not necessary since I was trying to do it. IMHO is to eliminate the self.errWin2Timer from memory (although it seems that there was a typo since you use errWin2 instead of errWin2Timer) but being son of the window is not necessary since in Qt if the parent dies the children will also die.
from PyQt4 import QtCore,QtGui
class ErrorWindow2(QtGui.QWidget):
def __init__( self ):
super(ErrorWindow2, self).__init__(None, QtCore.Qt.WindowStaysOnTopHint)
self.errWin2Timer = QtCore.QTimer(self,
interval=10*1000,
singleShot=True,
timeout=self.close)
self.errWin2Timer.start()
QtCore.QTimer.singleShot(0, self.showMessageBox)
def showMessageBox(self):
msgBox = QtGui.QMessageBox(self)
msgBox.move (500,500)
msgBox.setIcon(QtGui.QMessageBox.Critical)
msgBox.setText("Test 2")
ret = msgBox.exec_()
if ret == QtGui.QMessageBox.Ok:
print("OK")
if __name__ == '__main__':
import sys
app = QtGui.QApplication(sys.argv)
w = ErrorWindow2()
w.show()
sys.exit(app.exec_())

Related

How to dim background when using qmessagebox?

I want to set the background in dim mode, when a QMessagebox is popped up.
Currently, I have tried to use a simple QMesssagebox, but the background shows as normal display, when it pops up.
The image for 1st page is as follow
When go to next slide is pushed, it goes to next index as follow
When going back to 1st index, the back button is pushed which pops up the messagebox as follow
However, the mainwindow seems to have no effect on its focus.
Therefore, what would I need to do to make it dimmer than the focused messagebox.
How can I do this? Any suggestions?
EDIT
import sys
from PyQt5 import uic
from PyQt5.QtWidgets import QApplication, QMainWindow, QMessageBox
class MainWindow(QMainWindow):
def __init__(self):
super().__init__()
self.ui = uic.loadUi("message.ui",self)
self.notification = QMessageBox()
self.ui.next_slide.clicked.connect(self.second_index)
self.ui.go_back.clicked.connect(self.alert_msg)
self.show()
def home(self):
self.ui.stackedWidget.setCurrentIndex(0)
def second_index(self):
self.ui.stackedWidget.setCurrentIndex(1)
def alert_msg(self):
self.notification.setWindowTitle("Exiting")
self.notification.setText("Are you sure, you want to exit")
self.notification.setIcon(QMessageBox.Critical)
self.notification.setStandardButtons(QMessageBox.Yes | QMessageBox.No)
self.back = self.notification.exec_()
if self.back == QMessageBox.Yes:
self.home()
else:
pass
if __name__ == "__main__":
app=QApplication(sys.argv)
mainwindow=MainWindow()
app.exec_()
You can create a custom widget that is a direct child of the window that has to be "dimmed", ensure that it always has the same size as that window, and just paint it with the selected color:
class Dimmer(QWidget):
def __init__(self, parent):
parent = parent.window()
super().__init__(parent)
parent.installEventFilter(self)
self.setAttribute(Qt.WA_DeleteOnClose)
self.adaptToParent()
self.show()
def adaptToParent(self):
self.setGeometry(self.parent().rect())
def eventFilter(self, obj, event):
if event.type() == event.Resize:
self.adaptToParent()
return super().eventFilter(obj, event)
def paintEvent(self, event):
qp = QPainter(self)
qp.fillRect(self.rect(), QColor(127, 127, 127, 127))
class MainWindow(QMainWindow):
# ...
def alert_msg(self):
dimmer = Dimmer(self)
# ...
self.back = self.notification.exec_()
dimmer.close()
Note that, unless you plan to reuse the "dim widget", it must be destroyed either by calling close() as done above (see the WA_DeleteOnClose flag) or using deleteLater(). Hiding it will not be enough.

revert rejected dialogue/form to show last accepted values on reopen

I'm setting up an "options" dialog in a program, where I can change some values and close the dialog with Ok/Cancel to accept of reject my changes. After closing the dialog with cancel and reopening it, i would like the last accepted values to be displayed, however I am know sure how to implement this.
Below is a very simplified version of my code. I chose to instanciate the dialog only once (as opposed to creating a new instance each time I call the dialog), mainly to avoid having to call the __init__ and import data from save files each time I open the dialog.
from PyQt5.QtWidgets import QMainWindow, QPushButton,\
QApplication, QTextEdit, QDialog, QDialogButtonBox
class MainWindow(QMainWindow):
def __init__(self):
super().__init__()
btn = QPushButton('open text 1', self)
btn.move(10, 10)
btn.clicked.connect(self.open_dlg)
self.txtdlg = TextDialog()
def open_dlg(self):
if self.txtdlg.exec_() == QDialog.Accepted:
print(self.txtdlg.preferences)
class TextDialog(QDialog):
def __init__(self):
super().__init__()
self.preferences = "text here"
self.resize(200, 150)
self.textedit = QTextEdit(self)
self.textedit.resize(200, 100)
self.textedit.setText(self.preferences)
btns = QDialogButtonBox(QDialogButtonBox.Ok | QDialogButtonBox.Cancel, self)
btns.move(20, 100)
btns.accepted.connect(self.save_and_close)
btns.rejected.connect(self.reject)
def save_and_close(self):
self.preferences = self.textedit.toPlainText()
self.accept()
if __name__ == '__main__':
import sys
app = QApplication(sys.argv)
MW = MainWindow()
MW.show()
sys.exit(app.exec_())
As it is, after clicking Cancel the dialog keeps any unsaved changes to its widgets if I reopen it. My fist idea was to connect the cancel button to a close_without_saving method that updates the dialog to the last saved values before closing, but the displayed values will not be up to date if preferences is changed for some reason while the dialog is invisible. Can I run some code when i call exec_ ? Or is the logic behind my implementation wrong somehow?
You have to implement a method that sets the values of the dialog to the default values:
# ...
class MainWindow(QMainWindow):
# ...
def open_dlg(self):
self.txtdlg.reset()
if self.txtdlg.exec_() == QDialog.Accepted:
print(self.txtdlg.preferences)
class TextDialog(QDialog):
# ...
def reset(self):
self.preferences = "text here"
self.textedit.setText(self.preferences)
def save_and_close(self):
self.preferences = self.textedit.toPlainText()
self.accept()
# ...

Terminating QWidget doesn't work

I used self.close to close the widget that is running. Whole code is as follows:
class timeTracker(QWidget):
'''time tracker main application v_0.8'''
def __init__(self, parent=None):
super(timeTracker, self).__init__(parent)
self.grid = QGridLayout()
self.setLayout(self.grid)
while not self.connectivity():
print(self.connectivity())
ret = QMessageBox.warning(self, "Not connected to network. Please check the connection", "", QMessageBox.Yes | QMessageBox.No, QMessageBox.Yes)
if ret == QMessageBox.No:
self.close()
qApp.quit()
break
qApp.quit()
# self.time_widget = timeline.timeWidget()
# self.grid.addWidget(self.time_widget, 0, 0)
def connectivity(self):
try:
urllib.request.urlopen("http://www.google.com", timeout=1)
return True
except urllib.error.URLError as error:
return False
if __name__ == "__main__":
application = QApplication(sys.argv)
main_widget = timeTracker()
main_widget.show()
main_widget.move(10, 10)
sys.exit(application.exec_())
What I expect from this code is, as long as the connectivity function is returning True, user will be repeatedly asked to do the certain action if they click yes. If they click no, I would like to terminate the whole widget. But when I click no, then it just goes through the lines after the self.close. What can I do to actually terminate the program?
To close an application forcefully as in this case we can use sys.exit()
if ret == QMessageBox.No:
sys.exit(0)

PyQt Make parent GUI wait till child GUI is closed

I am new to pyqt.I am trying to invoke a child GUI when a button is clicked in the parent GUI. In this process, parent GUI has to wait for the child GUI to be closed by the user after selecting some inputs. But this is not happening, Parent GUI does execute the next lines after which the child GUI has been invoked. Below is the code where I am passing an argument to child GUI from parent GUI. The child GUI will return value based on OK/Cancel button click
Code:
import sys
from PyQt4 import QtGui,QtCore,Qt
from PyQt4.QtCore import *
from PyQt4.QtGui import *
class Child(QtGui.QWidget):
def __init__(self,switches=None):
super(Child,self).__init__()
self.swwidget = QtGui.QWidget()
self.swlayout = QtGui.QGridLayout()
switches = ['abc1','def1']
switches.sort()
self.switches = switches
def switchesUI(self):
self.swwidget.setWindowModality(QtCore.Qt.ApplicationModal)
self.swl = len(self.switches)
self.sw = {}
self.addsw = []
print ("I am in switchesUI")
#Add the switches to layout dynamically
for i in range(self.swl):
self.sw[i] = QtGui.QCheckBox(self.switches[i])
self.swlayout.addWidget(self.sw[i],i,0)
self.swbuttonbox = QtGui.QDialogButtonBox(QDialogButtonBox.Ok | QDialogButtonBox.Cancel);
self.swbuttonbox.setOrientation(QtCore.Qt.Horizontal)
self.swlayout.addWidget(self.swbuttonbox)
self.swwidget.setWindowTitle('Switches')
self.swwidget.setLayout(self.swlayout)
self.swwidget.show()
self.connect(self.swbuttonbox,QtCore.SIGNAL("accepted()"),self.swaccept)
self.connect(self.swbuttonbox,QtCore.SIGNAL("rejected()"),self.swreject)
def swaccept(self):
for i in range(self.swl):
if self.sw[i].isChecked():
self.addsw.append(self.switches[i])
self.swwidget.close()
return self.addsw
def swreject(self):
self.swwidget.close()
return None
class Parent(QtGui.QWidget):
def __init__(self):
super(Parent,self).__init__()
QtGui.QWidget.__init__(self)
self.button = QtGui.QPushButton('Test', self)
self.layout = QtGui.QVBoxLayout(self)
self.layout.addWidget(self.button)
self.assw = ['Test1','Test2']
self.CH = Child(self.assw)
self.connect(self.button,SIGNAL("clicked()"),self.popup)
print ("Child GUI closed")
def popup(self):
self.CH.switchesUI()
def main():
app = QtGui.QApplication(sys.argv)
form = Parent()
form.show()
sys.exit(app.exec_())
if __name__ == '__main__':
main()
After the button "Test" is clicked, a child GUI will pop-up. I don't want the statement "Child GUI Closed" to be printed till the child GUI is closed.
Can someone suggest me how to achieve this functionality ?
You have to handle closeEvent to perform operations when a window wants to close, also since your Child class inherits from QWidget which means it's a QWidget itself you dont need to create another one with self.swwidget
import sys
from PyQt4 import QtGui,QtCore,Qt
from PyQt4.QtCore import *
from PyQt4.QtGui import *
class Child(QtGui.QWidget):
def __init__(self,switches=None):
super(Child,self).__init__()
# self.swwidget = QtGui.QWidget() # you don't need to do this you can add all the properties to self
self.swlayout = QtGui.QGridLayout()
switches = ['abc1','def1']
switches.sort()
self.switches = switches
def switchesUI(self):
self.setWindowModality(QtCore.Qt.ApplicationModal)
self.swl = len(self.switches)
self.sw = {}
self.addsw = []
print ("I am in switchesUI")
#Add the switches to layout dynamically
for i in range(self.swl):
self.sw[i] = QtGui.QCheckBox(self.switches[i])
self.swlayout.addWidget(self.sw[i],i,0)
self.swbuttonbox = QtGui.QDialogButtonBox(QDialogButtonBox.Ok | QDialogButtonBox.Cancel);
self.swbuttonbox.setOrientation(QtCore.Qt.Horizontal)
self.swlayout.addWidget(self.swbuttonbox)
self.setWindowTitle('Switches')
self.setLayout(self.swlayout)
self.show()
self.connect(self.swbuttonbox,QtCore.SIGNAL("accepted()"),self.swaccept)
self.connect(self.swbuttonbox,QtCore.SIGNAL("rejected()"),self.swreject)
def swaccept(self):
for i in range(self.swl):
if self.sw[i].isChecked():
self.addsw.append(self.switches[i])
self.close()
return self.addsw
def swreject(self):
self.close()
return None
def closeEvent(self, event):
print ("Child GUI closed")
class Parent(QtGui.QWidget):
def __init__(self):
super(Parent,self).__init__()
QtGui.QWidget.__init__(self)
self.button = QtGui.QPushButton('Test', self)
self.layout = QtGui.QVBoxLayout(self)
self.layout.addWidget(self.button)
self.assw = ['Test1','Test2']
self.CH = Child(self.assw)
self.connect(self.button,SIGNAL("clicked()"),self.popup)
def popup(self):
self.CH.switchesUI()
def main():
app = QtGui.QApplication(sys.argv)
form = Parent()
form.show()
sys.exit(app.exec_())
if __name__ == '__main__':
main()

PyQT4 QWidget must receive 'close' signal twice before closing

I'm writing a PyQT4 (4.11) program that performs a long slow task which ideally needs a progress bar. The program works almost perfectly if I don't use threads, sub-classing a QWidget which only contains a QProgressBar and a layout. Instantiating this sub-class as form, I can call form.show() to put it on screen, and then my long slow loop can update the progress by calling form.progressbar.setValue(progress). There are two problems with this:
if the user tries to interact with the window they get 'not responding' messages from the windows manager/OS desktop process. This is because events are not being processed.
because events aren't being processed, the user can't cancel the long slow loop by closing the window.
So I tried making the long slow loop run in a separate thread, using a signal to update the progress bar. I overrode the closeEvent of my QWidget so that it can cancel interaction with the hardware device (all wrapped in mutexes so the device communication doesn't get out of sync). Again, this almost works. If I cancel, the application quits. If I leave it to run to completion though, I have to close the window manually (i.e. click the close icon or press alt-f4), even though I'm sending a close signal to the QWidget. As you can see in the code below there are some complications, since the app can't close immediately if cancelled, because it has to wait for some hardware clean up to happen. Here is a minimal version of my code
import sys
import os
import time
from PyQt4 import QtCore, QtGui
class Ui_ProgressBarDialog(QtGui.QWidget):
def __init__(self, on_close=None):
QtGui.QWidget.__init__(self)
self.setupUi(self)
self.center()
#on_close is a function that is called to cancel
#the long slow loop
self.on_close = on_close
def center(self):
qr = self.frameGeometry()
cp = QtGui.QDesktopWidget().availableGeometry().center()
qr.moveCenter(cp)
self.move(qr.topLeft())
def setupUi(self, ProgressBarDialog):
ProgressBarDialog.setObjectName(_fromUtf8("ProgressBarDialog"))
ProgressBarDialog.resize(400, 33)
self.verticalLayout = QtGui.QVBoxLayout(ProgressBarDialog)
self.verticalLayout.setObjectName(_fromUtf8("verticalLayout"))
self.progressBar = QtGui.QProgressBar(ProgressBarDialog)
self.progressBar.setProperty("value", 0)
self.progressBar.setObjectName(_fromUtf8("progressBar"))
self.verticalLayout.addWidget(self.progressBar)
self.retranslateUi(ProgressBarDialog)
#This allows the long slow loop to update the progress bar
QtCore.QObject.connect(
self,
QtCore.SIGNAL("updateProgress"),
self.progressBar.setValue
)
#Catch the close event so we can interrupt the long slow loop
QtCore.QObject.connect(
self,
QtCore.SIGNAL("closeDialog"),
self.closeEvent
)
#Repaint the window when the progress bar's value changes
QtCore.QObject.connect(
self.progressBar,
QtCore.SIGNAL("valueChanged(int)"),
self.repaint
)
QtCore.QMetaObject.connectSlotsByName(ProgressBarDialog)
def retranslateUi(self, ProgressBarDialog):
ProgressBarDialog.setWindowTitle("Please Wait")
def closeEvent(self, event, force=False):
if self.on_close is not None and not force:
self.on_close()
app = QtGui.QApplication(sys.argv)
filename = str(QtGui.QFileDialog.getSaveFileName(
None,
"Save as",
os.getcwd(),
"Data files: (*.dat)"
))
loop_mutex = thread.allocate_lock()
cancelled = False
can_quit = False
result = None
def cancel_download():
global cancelled
if can_quit:
return
if QtGui.QMessageBox.question(
None,
'Cancel Download',
"Are you sure you want to cancel the download?",
QtGui.QMessageBox.Yes | QtGui.QMessageBox.No,
QtGui.QMessageBox.No) == QtGui.QMessageBox.Yes:
with loop_mutex:
selected_device.cancelDownload()
cancelled = True
while not can_quit:
time.sleep(0.25)
form = ProgressBarDialog.Ui_ProgressBarDialog(cancel_download)
form.setWindowTitle("Please Wait")
form.progressBar.setMaximum(1000)
form.progressBar.setValue(0)
form.show()
def long_slow_loop(mutex, filename):
global can_quit, result
progress = 0
temp_binary_file = open(filename, "wb")
#The iterator below does the actual work of interacting with a
#hardware device, so I'm locking around the "for" line. I must
#not fetch more data from the device while a cancel command is
#in progress, and vice versa
mutex.acquire()
for data in ComplexIteratorThatInteractsWithHardwareDevice():
mutex.release()
temp_binary_file.write(datablock)
progress += 1
form.emit(QtCore.SIGNAL("updateProgress"), progress)
mutex.acquire()
if cancelled:
break
mutex.release()
result = not cancelled
temp_binary_file.close()
if cancelled:
os.unlink(filename)
#having set can_quit to True the following emission SHOULD
#cause the app to exit by closing the last top level window
can_quit = True
form.emit(QtCore.SIGNAL("closeDialog"), QtGui.QCloseEvent(), True)
thread.start_new_thread(do_dump, (loop_mutex, filename))
app.exec_()
if result == True:
QtGui.QMessageBox.information(None, 'Success', "Save to disk successful", QtGui.QMessageBox.Ok)
It turns out the secret is to use a QThread which emits some signals when the thread exits. Either "finished" or "terminated" depending on whether the exit was normal or abnormal. Here's some code
import sys
import os
import time
from PyQt4 import QtCore, QtGui
class Ui_ProgressBarDialog(QtGui.QWidget):
def __init__(self, process, parent = None):
QtGui.QWidget.__init__(self, parent)
self.thread = process
self.setupUi(self)
self.center()
self.thread.start()
def center(self):
qr = self.frameGeometry()
cp = QtGui.QDesktopWidget().availableGeometry().center()
qr.moveCenter(cp)
self.move(qr.topLeft())
def setupUi(self, ProgressBarDialog):
ProgressBarDialog.setObjectName("ProgressBarDialog")
ProgressBarDialog.resize(400, 33)
self.verticalLayout = QtGui.QVBoxLayout(ProgressBarDialog)
self.verticalLayout.setObjectName("verticalLayout")
self.progressBar = QtGui.QProgressBar(ProgressBarDialog)
self.progressBar.setProperty("value", 0)
self.progressBar.setObjectName("progressBar")
self.verticalLayout.addWidget(self.progressBar)
self.retranslateUi(ProgressBarDialog)
#Close when the thread finishes (normally)
QtCore.QObject.connect(
self.thread,
QtCore.SIGNAL("finished()"),
self.close
)
#Close when the thread is terminated (exception, cancelled etc)
QtCore.QObject.connect(
self.thread,
QtCore.SIGNAL("terminated()"),
self.close
)
#Let the thread update the progress bar position
QtCore.QObject.connect(
self.thread,
QtCore.SIGNAL("updateProgress"),
self.progressBar.setValue
)
#Repaint when the progress bar value changes
QtCore.QObject.connect(
self.progressBar,
QtCore.SIGNAL("valueChanged(int)"),
ProgressBarDialog.repaint
)
QtCore.QMetaObject.connectSlotsByName(ProgressBarDialog)
def retranslateUi(self, ProgressBarDialog):
ProgressBarDialog.setWindowTitle("Please Wait")
def closeEvent(self, event):
if self.thread.exit_status == self.thread.RUNNING:
if QtGui.QMessageBox.question(None, 'Cancel Download', "Are you sure you want to cancel the download?", QtGui.QMessageBox.Yes | QtGui.QMessageBox.No, QtGui.QMessageBox.No) == QtGui.QMessageBox.Yes:
if self.thread.exit_status == self.thread.RUNNING:
self.thread.exiting = True
while self.thread.exiting:
time.sleep(0.25)
elif self.thread.exit_status == self.thread.SUCCESS:
self.thread.exit_status = self.thread.CANCELLED
else:
if self.thread.exit_status == self.thread.RUNNING:
event.ignore()
app = QtGui.QApplication(sys.argv)
filename = str(QtGui.QFileDialog.getSaveFileName(
None,
"Save as",
os.getcwd(),
"Data files: (*.dat)"
))
class DeviceDataStreamHandler(QtCore.QThread):
RUNNING = 1
SUCCESS = 0
FAILURE = -1
CANCELLED = -2
class CancelledError(Exception):
pass
def __init__(self, parent = None, **kwargs):
QtCore.QThread.__init__(self, parent)
self.exiting = False
self.exit_status = DeviceDataStreamHandler.RUNNING
self.device = device
self.filename = filename
def run(self):
progress = 0
try:
temp_binary_file = open(self.filename, "wb")
#getDataStream is an interator returing strings
for data in self.device.getDataStream():
temp_binary_file.write(data)
progress += 1
self.emit(QtCore.SIGNAL("updateProgress"), progress)
if self.exiting:
raise DeviceDataStreamHandler.CancelledError()
self.exit_status = DeviceDataStreamHandler.SUCCESS
except DeviceDataStreamHandler.CancelledError:
self.exit_status = DeviceDataStreamHandler.CANCELLED
self.device.cancelDownload()
except Exception as E:
self.exit_status = DeviceDataStreamHandler.FAILURE
self.error_details = str(E)
finally:
temp_binary_file.close()
if self.exit_status == DeviceDataStreamHandler.CANCELLED:
os.unlink(filename)
self.exiting = False
class HardwareDeviceObject(object):
def __init__(self):
#initialises comms with a hardware device
self.event_count = 0
self.capture = False
def startCapture(self):
self.capture = True
def cancelDownload():
self.capture = False
def read(self):
#returns a string sent from the device
time.sleep(1)
self.event_count += 1
return self.event_count
def getDataStream(self):
class DataStreamIterator(object):
def __init__(self, ds, max_capture_count = 100):
self.ds = ds
self.capture_count = 0
self.max_capture_count = max_capture_count
def __iter__(self):
return self
def next(self):
#return string received from device
if self.ds.capture and self.capture_count < self.max_capture_count:
self.capture_count += 1
return self.ds.read()
else:
raise StopIteration()
self.startCapture()
return DataStreamIterator(self)
capture = DeviceDataStreamHandler(device = HardwareDeviceObject(), filename = filename)
form = ProgressBarDialog.Ui_ProgressBarDialog(capture)
form.setWindowTitle("Dumping sessions")
form.progressBar.setMaximum(100) #expect 100 outputs from the device
form.progressBar.setValue(0)
form.show()
app.exec_()
if capture.exit_status == DeviceDataStreamHandler.SUCCESS:
QtGui.QMessageBox.information(None, 'Success', "Save to disk successful", QtGui.QMessageBox.Ok)
elif capture.exit_status == DeviceDataStreamHandler.FAILURE:
QtGui.QMessageBox.critical(None, 'Error interacting with device', "{}".format(capture.error_details), QtGui.QMessageBox.Ok)

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