Checking endtime, starttime

sohstationviewer/view/main_window.py

@@ -368,6 +368,16 @@ class MainWindow(QtWidgets.QMainWindow, UIMainWindow):
         Read data from selected files/directories, process and plot channels
             read from those according to current options set on the GUI
         """
+
+        start_tm_str = self.time_from_date_edit.date().toString(
+            QtCore.Qt.ISODate)
+        end_tm_str = self.time_to_date_edit.date().toString(QtCore.Qt.ISODate)
+        self.start_tm = datetime.strptime(start_tm_str, TM_FORMAT).timestamp()
+        self.end_tm = datetime.strptime(end_tm_str, TM_FORMAT).timestamp()
+        if self.end_tm <= self.start_tm:
+            msg = "To Date must be greater than From Date."
+            QtWidgets.QMessageBox.warning(self, "Wrong Date Given", msg)
+            return
         self.info_list_widget.clear()
         is_working = (self.is_loading_data or self.is_plotting_soh or
                       self.is_plotting_waveform or self.is_plotting_tps)
@@ -424,12 +434,6 @@ class MainWindow(QtWidgets.QMainWindow, UIMainWindow):
         self.req_soh_chans = self.get_requested_soh_chan()
         self.req_wf_chans = self.get_requested_wf_chans()
 
-        start_tm_str = self.time_from_date_edit.date().toString(
-            QtCore.Qt.ISODate)
-        end_tm_str = self.time_to_date_edit.date().toString(QtCore.Qt.ISODate)
-        self.start_tm = datetime.strptime(start_tm_str, TM_FORMAT).timestamp()
-        self.end_tm = datetime.strptime(end_tm_str, TM_FORMAT).timestamp()
-
         self.data_loader.init_loader(
             self.data_type,
             self.tracking_info_text_browser,