PyQt5 - QTableView

[d_stranz]

the selectionChanged.connect just doesn't trigger the get_Details any longer.

I don't think you understand how signals and slots work. A connection (via connect()) between a signal (selectionChanged()) amd a slot (get_Details()) does not result in an immediate function call to the slot code.

What a connect() means is this: "In the future, when this signal is emitted by the signalling object instance (selectionModel), call this slot (get_Details()) and pass that slot the arguments provided by the signal". (Which in this case are the QModelIndex indexes that have been selected and deselected).

You do not call connect() every time you want to retrieve the new selection and pass that to the slot. You generally call connect() once when you are creating the object instances you are connecting. Thereafter, you simply wait for your slot to be called whenever the signalling object changes state.

You haven't posted enough of your code to verify what you are actually doing, but your description of how you are invoking connect() makes it seem like you have a misunderstanding of the protocol.

[szotke]

The bulk of the code is as follows. I have not included the SQL connection string as this works.

import sys
import datetime
from PyQt5 import QtWidgets as qtw
from PyQt5 import QtCore as qtc
from PyQt5 import QtGui as qtg
from PyQt5 import QtSql as qts
from PyQt5 import uic							
from PyQt5.QtSql import QSqlDatabase
 
MainWindow_Ui, MainWindow_Base = uic.loadUiType('CriticalAlarmListGUI.ui')
 
 
 
#class MainWindow(qtw.QMainWindow, Ui_MainWindow):
class MainWindow(MainWindow_Base, MainWindow_Ui):
	events = {}
 
	def __init__(self):
		"""MainWindow constructor.
 
		This widget will be the main window.
		Define all the UI components in here.
		"""
		super().__init__()
		# Main UI code goes here
		self.setupUi(self)
 
		# Connect to databases
                    #removed for security purposes
 
 
		# Build the Query
		StartDate = datetime.date(2020, 11, 1)
		EndDate = datetime.date.today()
 
		# Set the valid date range for the Calendar
		self.Calendar.setDateRange(StartDate, EndDate)
 
		# Format Dates for SQL
		StartDate = "'" + str(StartDate.strftime("%m/%d/%Y")) + "'"
		EndDate = "'" + str(EndDate.strftime("%m/%d/%Y")) + "'"
 
		# Get the list of critical alarms within the date range
		CriticalAlarms = self.get_Critical_Alarms(StartDate, EndDate)
 
		# Loop through the Critical Alarm list and update the calendar date format of the results
		for i in range(CriticalAlarms.rowCount()):
			datetime_str = CriticalAlarms.record(i).value("EventStamp")
			datetime_obj = datetime.datetime.strptime(datetime_str, '%Y-%m-%d %H:%M:%S.%f0')
 
			# Update the format of the date on the calendar day that the alarm occured
			format = qtg.QTextCharFormat()
			format.setFont(qtg.QFont('Times', 15))
			date = qtc.QDate(datetime_obj)			
			self.Calendar.setDateTextFormat(date, format)
 
		# Single Date Selected on the Calendar
		self.Calendar.selectionChanged.connect(self.config_Critical_Alarms)
 
		# Single record selected on the CriticalAlarmList widget
		self.CriticalAlarmList.selectionModel().selectionChanged.connect(self.get_Critical_Alarm_Details)
 
		# End main UI code
		self.show()
 
 
	def config_Critical_Alarms(self):
		print ("config_Critical_Alarms")
		CriticalAlarms = None
		StartDate = self.Calendar.selectedDate()
		EndDate = StartDate.addDays(1)
 
		StartDate = "'" + qtc.QDate.toString(StartDate, 'MM/dd/yyyy') + "'"
		EndDate = "'" + qtc.QDate.toString(EndDate, 'MM/dd/yyyy') + "'"
		CriticalAlarms = self.get_Critical_Alarms(StartDate, EndDate)
 
 
	def get_Critical_Alarms(self, StartDate, EndDate):
		print ("get_Critical_Alarms")
 
		alarm_state = "'UNACK_ALM'"
		queryString = f'SELECT EventStamp, TagName, Description, Priority FROM v_AlarmHistory WHERE (AlarmState = {alarm_state}) '\
			f'AND (EventStamp >= {StartDate}) AND (Priority <= 10) AND '\
			f'(EventStamp <= {EndDate}) ORDER BY EventStamp DESC'
 
		# Process the SQL Query
		CriticalAlarms = qts.QSqlQueryModel()
		CriticalAlarms.setQuery(queryString)
 
		self.CriticalAlarmList.setModel(CriticalAlarms)
		self.CriticalAlarmList.resizeColumnsToContents()
		self.StatusLabel.setText('Found {0} critical alarms between {1} and {2}'.format(CriticalAlarms.rowCount(), StartDate, EndDate))		
 
		return(CriticalAlarms)
 
 
	def get_Critical_Alarm_Details(self, selected):
		print ("get_Critical_Alarm_Details")
		indexes = self.CriticalAlarmList.selectionModel().selectedRows()
		model = self.CriticalAlarmList.model()
		for index in indexes:
			self.StatusLabel.setText('Selected row: {0}, Tag: {1}'.format(index.row(), model.data(model.index(index.row(), 1))))
 
 
	def UiComponents(self, datetime_obj):
		print ("UiComponents")
		# Calendar day format
		format = qtg.QTextCharFormat()
		format.setFont(qtg.QFont('Times', 15))
		date = qtc.QDate(datetime_obj)			
		value = self.Calendar.dateTextFormat()
		self.label.setWordWrap(True)
		self.label.setText("Date: " + str(value))
 
 
 
 
# Main
if __name__ == '__main__':
	app = qtw.QApplication(sys.argv)
	# Requirement to save a reference to MainWindow
	# if it goes out of scope, it will be destroyed.
	mw = MainWindow()
	sys.exit(app.exec())

import sys
import datetime
from PyQt5 import QtWidgets as qtw
from PyQt5 import QtCore as qtc
from PyQt5 import QtGui as qtg
from PyQt5 import QtSql as qts
from PyQt5 import uic							
from PyQt5.QtSql import QSqlDatabase

MainWindow_Ui, MainWindow_Base = uic.loadUiType('CriticalAlarmListGUI.ui')



#class MainWindow(qtw.QMainWindow, Ui_MainWindow):
class MainWindow(MainWindow_Base, MainWindow_Ui):
	events = {}

	def __init__(self):
		"""MainWindow constructor.

		This widget will be the main window.
		Define all the UI components in here.
		"""
		super().__init__()
		# Main UI code goes here
		self.setupUi(self)

		# Connect to databases
                    #removed for security purposes


		# Build the Query
		StartDate = datetime.date(2020, 11, 1)
		EndDate = datetime.date.today()

		# Set the valid date range for the Calendar
		self.Calendar.setDateRange(StartDate, EndDate)

		# Format Dates for SQL
		StartDate = "'" + str(StartDate.strftime("%m/%d/%Y")) + "'"
		EndDate = "'" + str(EndDate.strftime("%m/%d/%Y")) + "'"

		# Get the list of critical alarms within the date range
		CriticalAlarms = self.get_Critical_Alarms(StartDate, EndDate)

		# Loop through the Critical Alarm list and update the calendar date format of the results
		for i in range(CriticalAlarms.rowCount()):
			datetime_str = CriticalAlarms.record(i).value("EventStamp")
			datetime_obj = datetime.datetime.strptime(datetime_str, '%Y-%m-%d %H:%M:%S.%f0')

			# Update the format of the date on the calendar day that the alarm occured
			format = qtg.QTextCharFormat()
			format.setFont(qtg.QFont('Times', 15))
			date = qtc.QDate(datetime_obj)			
			self.Calendar.setDateTextFormat(date, format)

		# Single Date Selected on the Calendar
		self.Calendar.selectionChanged.connect(self.config_Critical_Alarms)

		# Single record selected on the CriticalAlarmList widget
		self.CriticalAlarmList.selectionModel().selectionChanged.connect(self.get_Critical_Alarm_Details)

		# End main UI code
		self.show()


	def config_Critical_Alarms(self):
		print ("config_Critical_Alarms")
		CriticalAlarms = None
		StartDate = self.Calendar.selectedDate()
		EndDate = StartDate.addDays(1)

		StartDate = "'" + qtc.QDate.toString(StartDate, 'MM/dd/yyyy') + "'"
		EndDate = "'" + qtc.QDate.toString(EndDate, 'MM/dd/yyyy') + "'"
		CriticalAlarms = self.get_Critical_Alarms(StartDate, EndDate)


	def get_Critical_Alarms(self, StartDate, EndDate):
		print ("get_Critical_Alarms")

		alarm_state = "'UNACK_ALM'"
		queryString = f'SELECT EventStamp, TagName, Description, Priority FROM v_AlarmHistory WHERE (AlarmState = {alarm_state}) '\
			f'AND (EventStamp >= {StartDate}) AND (Priority <= 10) AND '\
			f'(EventStamp <= {EndDate}) ORDER BY EventStamp DESC'

		# Process the SQL Query
		CriticalAlarms = qts.QSqlQueryModel()
		CriticalAlarms.setQuery(queryString)

		self.CriticalAlarmList.setModel(CriticalAlarms)
		self.CriticalAlarmList.resizeColumnsToContents()
		self.StatusLabel.setText('Found {0} critical alarms between {1} and {2}'.format(CriticalAlarms.rowCount(), StartDate, EndDate))		

		return(CriticalAlarms)


	def get_Critical_Alarm_Details(self, selected):
		print ("get_Critical_Alarm_Details")
		indexes = self.CriticalAlarmList.selectionModel().selectedRows()
		model = self.CriticalAlarmList.model()
		for index in indexes:
			self.StatusLabel.setText('Selected row: {0}, Tag: {1}'.format(index.row(), model.data(model.index(index.row(), 1))))


	def UiComponents(self, datetime_obj):
		print ("UiComponents")
		# Calendar day format
		format = qtg.QTextCharFormat()
		format.setFont(qtg.QFont('Times', 15))
		date = qtc.QDate(datetime_obj)			
		value = self.Calendar.dateTextFormat()
		self.label.setWordWrap(True)
		self.label.setText("Date: " + str(value))




# Main
if __name__ == '__main__':
	app = qtw.QApplication(sys.argv)
	# Requirement to save a reference to MainWindow
	# if it goes out of scope, it will be destroyed.
	mw = MainWindow()
	sys.exit(app.exec())

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I believe I have the signals and slots set up correctly. Please make any suggestions to why I do not get the continued function of the signal.

[d_stranz]

OK, I am not a Python expert, but what I think is happening is that in get_Critical_Alarms() you are setting a new model on your list. This causes the selectionModel() to become invalid, and therefore the selectionChanged() signal is disconnected.

Try adding the connect() statement after line 90.

[szotke]

Try adding the connect() statement after line 90.

That worked.

Thank you very much.

[d_stranz]

Sure. I think your original idea would work if you did not create a new CriticalAlarms model every time you make a query. If you make CriticalAlarms a member variable of your class, create it and connect to the selectionChanged() signal and then simply call setQuery() on that instance each time the calendar selection changes, your model will be reset with each query and the current selection will be cleared. The selection model won't be destroyed, it will just be cleared. The next time an item is selected, the selectionChanged() signal will be emitted.

So basically, remove line 87 above, remove the new connection you added after line 90 (keeping the original one from line 61), and make CriticalAlarms into self.CriticalAlarms. Then I think your original code will work. You probably don't have to change get_CriticalAlarms() return value since you'll be returning the same object reference (self.CriticalAlarms).