Create simple messagebox to report error in input value

[PyGrrl_FL]

Hello,

I am completely new to GUI development using Qt and have about 1 year of python programming. I am working on a project that involves connecting to Oracle database and creating a file for processing. If the result of the query returns a null dataset, I want to have a messagebox popup to inform the user that the information they entered is incorrect.

Here is my code so far:

*import sys
import os
import cx_Oracle
import csv
from datetime import datetime as dt
from PyQt5.QtWidgets import QApplication, QDialog, QLineEdit, QPushButton, QFormLayout, QLabel, QMessageBox
from invalid_popup import Ui_invalidPopup

class Form(QDialog):
def init(self, parent=None):
super(Form,self).init(parent)
self.setWindowTitle("Window Title")

    # Create widgets
    self.myCourseInput = QLineEdit(self)
    self.QCourseLabel = QLabel("Enter Course ID: ")
    self.submitBtn = QPushButton("SUBMIT")
    self.showdialog = QMessageBox

    # Create layout and add widgets
    layout = QFormLayout()
    layout.addRow(self.QCourseLabel,self.myCourseInput)
    layout.addRow(self.submitBtn)

    # Set dialog layout
    self.setLayout(layout)

    # Connect submit button to action
    self.submitBtn.clicked.connect(self.Submit_btn)

# Run code to generate files for grade dispute processing
def Submit_btn(self):
    Text = self.myCourseInput.text().upper() # Set any alpha input to uppercase

    # Connect to Oracle database
    os.putenv('ORACLE_HOME', <path to oracle home>)
    os.putenv('LD_LIBRARY_PATH',r"C:\oracle\instantclient_18_3")
    cnxn = cx_Oracle.connect(database connection info)
    cursor = cnxn.cursor()

    self.SQL1 = "select cm.BATCH_UID as EXTERNAL_COURSE_KEY, cm.COURSE_ID, cm.COURSE_NAME, cm.AVAILABLE_IND, cm.ROW_STATUS, ds.BATCH_UID as DATA_SOURCE_KEY from course_main cm, DATA_SOURCE ds where cm.COURSE_ID = :cid and ds.PK1 = cm.DATA_SRC_PK1"

    cursor.execute(self.SQL1, {'cid': (Text)})
    courseResults = cursor.fetchall()
    if courseResults == []:
        self.showdialog.show()
    else:
        dskCourse = str(courseResults[0][5])

        filename = (r"C:\Downloads\\" + dskCourse)
        gdCourseFile = open(filename,"w");
        output=csv.writer(gdCourseFile, delimiter = "|", lineterminator = "\n")
        header = ('EXTERNAL_COURSE_KEY', 'COURSE_ID', 'COURSE_NAME', 'AVAILABLE_IND', 'ROW_STATUS', 'DATA_SOURCE_KEY', 'NEW_DATA_SOURCE_KEY')
        output.writerow(header)
        ctr = 0
        for row in courseResults:
            if row[4] == 2:
                ctr += 1
                rowStatus = 'ENABLED'
                newRow = list(row)
                newRow[3] = 'Y'
                newRow[4] = (str(rowStatus)) #Update the row_status of the course to enable for the grade dispute
                newRow.append('SYSTEM')
                output.writerow(newRow)

                #Create footer for feed file
                currentDt = dt.now()
                today = currentDt.strftime('%H:%M:%S %m/%d/%Y')
                footer = ('***FileFooter', str(ctr), today)
                output.writerow(footer)
                return(self.myCourseInput.text())
            else:
                return(self.myCourseInput.text())

        gdCourseFile.close()

    cnxn.commit()
    cursor.close()
    cnxn.close()
    print("Connection closed.")

def showdialog(QDialog):
   msg = QMessageBox()
   msg.setIcon(QMessageBox.Information)
   msg.setText("There are no results for the value entered.")
   msg.setWindowTitle("Invalid Entry")
   msg.setStandardButtons(QMessageBox.Ok)

Create the Qt Application

app = QApplication(sys.argv)

Create and show the form

form = Form()
form.show()

Run the main Qt loop

sys.exit(app.exec())*

[SGaist]

Hi and welcome to devnet,

You should use the equivalent of the QMessageBox::information static method.

if not courseResults:
   QMessageBox.information(self, 
                           self.tr("Invalid Entry")
                           self.tr("There are no results for the value entered."))

[PyGrrl_FL]

@SGaist Thank you! Thank you! It does exactly what I need! Can you explain what the "self.tr" means? (Noob question, I'm sure. :))

[SGaist]

It's the method used for application internationalisation/translation. It's not mandatory but I have the habit of making all strings shown to the users ready for translation.

[PyGrrl_FL]

Thanks for the explanation!