mujeebalikhan88

This question got resolved

I put in his code

void getUID() {
  FirebaseAuth auth = FirebaseAuth.instance;
  User? user = auth.currentUser;
  if (user != null) {
    setState(() {
      uid = user.uid;
    });
  }
}

When I run the flutter program I now get this error  msg

======== Exception caught by widgets library =======================================================
The following assertion was thrown building TaskListPage(dirty, state: _TaskListPageState#61ebf):
a document path must be a non-empty string
'package:cloud_firestore/src/collection_reference.dart':
Failed assertion: line 116 pos 14: 'path.isNotEmpty'

When the exception was thrown, this was the stack: 
#2      _JsonCollectionReference.doc (package:cloud_firestore/src/collection_reference.dart:116:14)
#3      _TaskListPageState.build (package:todolist/pages/tasklist/tasklist.dart:75:16)
#4      StatefulElement.build (package:flutter/src/widgets/framework.dart:5080:27)
#5      ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4968:15)
#6      StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:5133:11)
#7      Element.rebuild (package:flutter/src/widgets/framework.dart:4690:5)
#8      ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4950:5)
#9      StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:5124:11)
#10     ComponentElement.mount (package:flutter/src/widgets/framework.dart:4944:5)
#11     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3953:16)
#12     Element.updateChild (package:flutter/src/widgets/framework.dart:3676:20)
#13     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4993:16)
#14     StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:5133:11)
#15     Element.rebuild (package:flutter/src/widgets/framework.dart:4690:5)
#16     BuildOwner.buildScope (package:flutter/src/widgets/framework.dart:2743:19)
#17     WidgetsBinding.drawFrame (package:flutter/src/widgets/binding.dart:863:21)
#18     RendererBinding._handlePersistentFrameCallback (package:flutter/src/rendering/binding.dart:381:5)
#19     SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:1289:15)
#20     SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:1218:9)
#21     SchedulerBinding._handleDrawFrame (package:flutter/src/scheduler/binding.dart:1076:5)
#22     _invoke (dart:ui/hooks.dart:145:13)
#23     PlatformDispatcher._drawFrame (dart:ui/platform_dispatcher.dart:338:5)
#24     _drawFrame (dart:ui/hooks.dart:112:31)
(elided 2 frames from class _AssertionError)
====================================================================================================

Screenshot of my emulator

can u also upload on how to start with ros?