Animation failed assertion flutter

Question

This assertion follows me around using different codes for some reason now, searching about it and found that the flutter team hasn't solved it yet for a while now, is there anything we can do?

v`I/flutter ( 5598): Another exception was thrown: 
'package:flutter/src/animation/animations.dart': Failed assertion: line 
376 pos 15: 'parent != null': is not true.
I/chatty  ( 5598): uid=10085(com.example.gam3ity_aa) 1.ui identical 21 
lines
I/flutter ( 5598): Another exception was thrown: 
'package:flutter/src/animation/animations.dart': Failed assertion: line 
376 pos 15: 'parent != null': is not true.
I/flutter ( 5598): Another exception was thrown: 
'package:flutter/src/animation/animations.dart': Failed assertion: line 
376 pos 15: 'parent != null': is not true.
I/chatty  ( 5598): uid=10085(com.example.gam3ity_aa) 1.ui identical 10 
lines
I/flutter ( 5598): Another exception was thrown: 
'package:flutter/src/animation/animations.dart': Failed assertion: line 
376 pos 15: 'parent != null': is not true.
I/flutter ( 5598): Another exception was thrown: 
'package:flutter/src/animation/animations.dart': Failed assertion: line 
376 pos 15: 'parent != null': is not true.
I/chatty  ( 5598): uid=10085(com.example.gam3ity_aa) 1.ui identical 8 
lines
I/flutter ( 5598): Another exception was thrown: 
'package:flutter/src/animation/animations.dart': Failed assertion: line 
376 
 pos 15: 'parent != null': is not true.

`

Answer 1

This was happening for me when accidentally creating a Tween object with (parent: null)

  @override
  void initState() {
    _animation = Tween(begin: 0.0, end: 1.0).animate(CurvedAnimation(
      parent: null, // <---------------- This line should be an AnimationController
      curve: widget.curve,
      reverseCurve: widget.reverseCurve ?? widget.curve,
    ));
    super.initState();
  }

It should have been like this:

  AnimationController _animationController;
  Animation _animation;

  @override
  void initState() {
    _animationController = AnimationController(
        duration: Duration(milliseconds: 500),
        reverseDuration: Duration(milliseconds: 1000),
        vsync: this,
        value: 1.0
    );
    _animation = Tween(begin: 0.0, end: 1.0).animate(CurvedAnimation(
      parent: _animationController,
      curve: widget.curve,
      reverseCurve: widget.reverseCurve ?? widget.curve,
    ));
    super.initState();
  }