Improve date picker flow handling

PR #572

Author: Apprentice2907

lib/app/utils/add_task_dialogue/date_picker_input.dart

@@ -106,11 +106,36 @@ class _AddTaskDatePickerInputState extends State<AddTaskDatePickerInput> {
           firstDate: DateTime.now(),
           lastDate: DateTime(2101),
         );
+        
+        // FIX: Check if date was selected before showing time picker
+        if (picked == null) {
+          return; // User canceled date picker, exit early
+        }
+        
+        // Only show time picker if date was selected
         final TimeOfDay? time = await showTimePicker(
           context: context,
           initialTime: TimeOfDay.now(),
         );
-        if (picked == null || time == null) return;
+        
+        // If user cancels time picker, still set the date with default time
+        if (time == null) {
+          setState(() {
+            // Set date with end-of-day time (23:59)
+            _selectedDates[forIndex] = picked.add(
+              const Duration(hours: 23, minutes: 59),
+            );
+            // Update the controller text
+            _controllers[forIndex].text =
+                dateToStringForAddTask(_selectedDates[forIndex]!);
+          });
+          if (widget.onDateChanges != null) {
+            widget.onDateChanges!(_selectedDates);
+          }
+          return;
+        }
+        
+        // Both date and time selected
         setState(() {
           _selectedDates[forIndex] =
               picked.add(Duration(hours: time.hour, minutes: time.minute));
@@ -135,4 +160,4 @@ class _AddTaskDatePickerInputState extends State<AddTaskDatePickerInput> {
     }
     return null;
   }
-}
+}