Use an enum to define the thread status

download_window.py

@@ -1,7 +1,7 @@
 from PyQt5 import uic
 from PyQt5.QtCore import Qt, pyqtSlot
 from PyQt5.QtWidgets import QWidget, QMessageBox
-from download_thread import DownloadThread
+from threads import DownloadThread, ThreadStatus
 Ui_Download_window, _ = uic.loadUiType("download_db_window.ui")
 
 class DownloadWindow(QWidget, Ui_Download_window):
@@ -37,18 +37,15 @@ class DownloadWindow(QWidget, Ui_Download_window):
 
         self.download_thread = DownloadThread(db_location, data_folder)
         self.download_thread.finished.connect(self.wait_close)
-        self.download_thread.no_connection_error.connect(self.show_no_connection_warning)
-        self.download_thread.bad_db_download_error.connect(self.show_bad_download_warning)
 
         self.cancel_btn.clicked.connect(self.terminate_process)
 
-    @pyqtSlot()
     def show_no_connection_warning(self):
-        self.bad_db_download_msg.setText(f"Unable to correctly download the database.\nReason: {self.download_thread.reason}")
+        self.bad_db_download_msg.setText(f"""Unable to correctly download the database.
+        Reason: {self.download_thread.reason}""")
         self.no_internet_msg.show()
         self.everything_ok = False
 
-    @pyqtSlot()
     def show_bad_download_warning(self):
         self.bad_db_download_msg.show()
         self.everything_ok = False
@@ -62,7 +59,13 @@ class DownloadWindow(QWidget, Ui_Download_window):
 
     @pyqtSlot()
     def wait_close(self):
-        if self.download_thread.regular_execution:
+        if self.download_thread.status == ThreadStatus.ok:
+            self.close()
+        elif self.download_thread.status == ThreadStatus.no_connection_err:
+            self.show_no_connection_warning()
+        elif self.download_thread.status == ThreadStatus.bad_download_err:
+            self.show_bad_download_warning
+        else:
             self.close()
 
     def reject(self):

main.py

@@ -55,7 +55,6 @@ class MyApp(QMainWindow, Ui_MainWindow):
         self.setupUi(self)
         self.set_initial_size()
         self.download_window = DownloadWindow(self.db_location, self.data_folder)
-        self.show()
         self.actionExit.triggered.connect(qApp.quit)
         self.action_update_database.triggered.connect(self.download_db)
         self.db_version = None
@@ -289,6 +288,9 @@ class MyApp(QMainWindow, Ui_MainWindow):
                                 self.description_text,]
 
         self.url_button.clicked.connect(self.go_to_web_page_signal)
+
+        self.show()
+
         self.load_db()
         self.display_signals()
         self.search_bar.textChanged.connect(self.display_signals)

threads.py

@@ -1,24 +1,31 @@
+from enum import Enum, auto
 from io import BytesIO
 from os import mkdir
 import os.path
 from shutil import rmtree
 import urllib3
 from zipfile import ZipFile
-from PyQt5.QtCore import QThread, pyqtSignal
+from PyQt5.QtCore import QThread
 import utilities
 
-class DownloadThread(QThread):
+class ThreadStatus(Enum):
-    no_connection_error = pyqtSignal()
+    ok = auto()
-    bad_db_download_error = pyqtSignal()
+    no_connection_err = auto()
-    bad_file_error = pyqtSignal()
+    no_file_err = auto()
+    bad_download_err = auto()
 
+class DownloadThread(QThread):
     def __init__(self, db_location, path):
         super().__init__()
         self.__db_location = db_location
         self.__path = path
-        self.regular_execution = True
+        self.__status = None
         self.reason = 0
 
+    @property
+    def status(self):
+        return self.__status
+
     def __del__(self):
         self.terminate()
         self.wait()
@@ -29,26 +36,27 @@ class DownloadThread(QThread):
             # db = urllib.request.urlopen(self.__db_location)
             # raise urllib.error.URLError('Test')
         except urllib3.exceptions.MaxRetryError: # No internet connection.
-            self.regular_execution = False
+            # self.no_connection_error.emit()
-            self.no_connection_error.emit()
+            self.__status = ThreadStatus.no_connection_err
             return
         if db.status != 200:
-            self.regular_execution = False
             self.reason = db.reason
-            self.bad_db_download_error.emit()
+            # self.bad_download_error.emit()
+            self.__status = ThreadStatus.bad_download_err
             return
         if not utilities.checksum_ok(db.data, "folder"):
-            regular_execution = False
+            # self.bad_download_error.emit()
-            self.bad_db_download_error.emit()
+            self.__status = ThreadStatus.bad_download_err
             return
         if os.path.exists(self.__path):
             rmtree(self.__path)
         try:
-        # data_folder = db.read()
+            # data_folder = db.read()
-            # data_folder = db.data
             with ZipFile(BytesIO(db.data)) as zipped:
                 zipped.extractall()
         except:
-            self.regular_execution = False
+            # self.bad_file_error.emit()
-            self.bad_file_error.emit()
+            self.__status = ThreadStatus.bad_file_err
             return
+        else:
+            self.__status = ThreadStatus.ok