Fix #7 with exception handler.

View/mainwindow.py

@@ -275,7 +275,15 @@ class Ui_MainWindow(object):
         cc_kt.exec()
 
     def db_browser_for_sqlite(self):
-        Popen(f"sqlitebrowser", shell=True)
+        try:
+            Popen("sqlitebrowser")
+        except OSError as e:
+            msg_box = QtWidgets.QMessageBox()
+            msg_box.setWindowTitle("DB Browser for SQLite Error")
+            msg_box.setIcon(QtWidgets.QMessageBox.Critical)
+            msg_box.setText(f"DB Browser for SQLite Error:\n  {str(e)}")
+            msg_box.setStandardButtons(QtWidgets.QMessageBox.Ok)
+            msg_box.exec()
 
     def about_window(self):
         print("about")