Hi there! Please add this one.

Could you please support null safety, so this library can be used in null safe project? Thank you.

A feature to specify a custom shadow color would be nice.

Hi great package. Will be nice to permit show or hide top or bottom fade.

I have a multi language app
The package works fine with LTR using FadingEdgeScrollView.fromScrollView
But its not functional with RTL
I think AlignmentDirectional should do the trick
Thank you for your efforts

I am using fading_edge_scrollview 3.0.0 on Flutter 2.10.3, and when I try to run my app I get these warnings:

C:/..../flutter/.pub-cache/hosted/pub.dartlang.org/fading_edge_scrollview-3.0.0/lib/src/fading_edge_scrollview.dart:196:10: Error: Method 'addPostFrameCallback' cannot be called on 'WidgetsBinding?' because it is potentially null.
- 'WidgetsBinding' is from 'package:flutter/src/widgets/binding.dart' ('/C:/..../flutter/packages/flutter/lib/src/widgets/binding.dart').
package:flutter/…/widgets/binding.dart:1
Try calling using ?. instead.
      it.addPostFrameCallback(_postFrameCallback);
         ^^^^^^^^^^^^^^^^^^^^

/C:/..../flutter/.pub-cache/hosted/pub.dartlang.org/fading_edge_scrollview-3.0.0/lib/src/fading_edge_scrollview.dart:197:10: Error: Method 'addObserver' cannot be called on 'WidgetsBinding?' because it is potentially null.
- 'WidgetsBinding' is from 'package:flutter/src/widgets/binding.dart' ('/C:/..../flutter/packages/flutter/lib/src/widgets/binding.dart').
package:flutter/…/widgets/binding.dart:1
Try calling using ?. instead.
      it.addObserver(this);

/C:/..../flutter/.pub-cache/hosted/pub.dartlang.org/fading_edge_scrollview-3.0.0/lib/src/fading_edge_scrollview.dart:220:29: Error: Method 'removeObserver' cannot be called on 'WidgetsBinding?' because it is potentially null.
- 'WidgetsBinding' is from 'package:flutter/src/widgets/binding.dart' ('/C:/..../flutter/packages/flutter/lib/src/widgets/binding.dart').
package:flutter/…/widgets/binding.dart:1
Try calling using ?. instead.
    WidgetsBinding.instance.removeObserver(this);

I did all the suggested changes in fading_edge_scrollview.dart and now it works.
Can you fix this in the repo?

I am using a SingleChildScrollView and inside is an AnimatedList that can automatically scroll down to the last item. I found that the effect only appeared when I was using my hand and scrolling. I want to know is there a way to make the Fading effect appear automatically when the Listview is scrollable?

Triggering Way:

1. I made a FadingEdgeScrollView.fromSingleChildScrollView with a ScrollController() and then nested it in a ListView.
2. I placed a PieMenu(https://pub.dev/packages/pie_menu, which has a LongPress gesture bounden) as a parent of the FadingEdgeScrollView.
3. When I did the long press, I was getting the ScrollController attached to multiple scroll views error.

Although involved, I think this problem is not connected with PieMenu, it's just one of the ways of triggering this error (triggerable by other done-by-user operations, too). The reason of the error is most probably affiliated with getting multiple positions.

Involved Version:

3.0.0, upon Flutter 3.16.

Full Error Output:

The following assertion was thrown during a scheduler callback:
ScrollController attached to multiple scroll views.
'package:flutter/src/widgets/scroll_controller.dart':
Failed assertion: line 158 pos 12: '_positions.length == 1'

When the exception was thrown, this was the stack: 
#2      ScrollController.position (package:flutter/src/widgets/scroll_controller.dart:158:12)
#3      _FadingEdgeScrollViewState._controllerIsReady (package:fading_edge_scrollview/src/fading_edge_scrollview.dart:202:45)
#4      _FadingEdgeScrollViewState._postFrameCallback (package:fading_edge_scrollview/src/fading_edge_scrollview.dart:210:9)
#5      SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:1325:15)
#6      SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:1264:9)
#7      SchedulerBinding._handleDrawFrame (package:flutter/src/scheduler/binding.dart:1113:5)
#8      _invoke (dart:ui/hooks.dart:312:13)
#9      PlatformDispatcher._drawFrame (dart:ui/platform_dispatcher.dart:383:5)
#10     _drawFrame (dart:ui/hooks.dart:283:31)
(elided 2 frames from class _AssertionError)

Solving Strategy:

I tested and found it solvable by https://stackoverflow.com/a/70672454/15439845. I'll make a pull request later.

Using fading_edge_scrollview 2.0.0, and I found this issue being reported quite often in our crashlytics console, which seems to point to an issue with the fact _isScrolledToEnd can be null based off the line it points to.
`

Non-fatal Exception: io.flutter.plugins.firebase.crashlytics.FlutterError: Null check operator used on a null value. Error thrown Instance of 'ErrorDescription'.
at ScrollPosition.maxScrollExtent(ScrollPosition.java:140)
at _FadingEdgeScrollViewState._postFrameCallback(_FadingEdgeScrollViewState.java:206)
at SchedulerBinding._invokeFrameCallback(SchedulerBinding.java:1144)
at SchedulerBinding.handleDrawFrame(SchedulerBinding.java:1090)
at SchedulerBinding._handleDrawFrame(SchedulerBinding.java:998)

I found out that you are creating constructors for no reason when you don't do anything special for each constructor :
here check these constructors they have the same implementation but with different constructor arguments :

  /// Constructor for creating [FadingEdgeScrollView] with [PageView] as child
  /// child must have [PageView.controller] set
  factory FadingEdgeScrollView.fromPageView({
    Key key,
    @required PageView child,
    double gradientFractionOnStart = 0.1,
    double gradientFractionOnEnd = 0.1,
    bool shouldDisposeScrollController = false,
  }) {
    assert(child.controller != null, "Child must have controller set");

    return FadingEdgeScrollView._internal(
      key: key,
      child: child,
      scrollController: child.controller,
      scrollDirection: child.scrollDirection,
      reverse: child.reverse,
      gradientFractionOnStart: gradientFractionOnStart,
      gradientFractionOnEnd: gradientFractionOnEnd,
      shouldDisposeScrollController: shouldDisposeScrollController,
    );
  }

  /// Constructor for creating [FadingEdgeScrollView] with [AnimatedList] as child
  /// child must have [AnimatedList.controller] set
  factory FadingEdgeScrollView.fromAnimatedList({
    Key key,
    @required AnimatedList child,
    double gradientFractionOnStart = 0.1,
    double gradientFractionOnEnd = 0.1,
    bool shouldDisposeScrollController = false,
  }) {
    assert(child.controller != null, "Child must have controller set");

    return FadingEdgeScrollView._internal(
      key: key,
      child: child,
      scrollController: child.controller,
      scrollDirection: child.scrollDirection,
      reverse: child.reverse,
      gradientFractionOnStart: gradientFractionOnStart,
      gradientFractionOnEnd: gradientFractionOnEnd,
      shouldDisposeScrollController: shouldDisposeScrollController,
    );
  }

why is that ?

Hello with flutter 3.10 I have pixelated children:

Before:

Flutter 3.10:

Any ideas to fix this ? Thx 😇

I've tested this package with 2 scrollviews I have in my app, the fade is only applying to the end of the scrollview, not the start.

A null pointer exception is thrown when using the FadingEdgeScrollView inside the TabBarView.

Steps to reproduce:

1. Clone this repo with a minimum code which reproduces the problem: shemhazai/flutter_fading_edge_scrollview
2. Navigate through pages by clicking on the TabBar tabs (must not be adjacent tabs).
3. The exception is thrown (as posted below).

I/flutter ( 6149): ══╡ EXCEPTION CAUGHT BY SCHEDULER LIBRARY >╞═════════════════════════════════════════════════════════
I/flutter ( 6149): The following NoSuchMethodError was thrown during a scheduler callback:
I/flutter ( 6149): The getter 'position' was called on null.
I/flutter ( 6149): Receiver: null
I/flutter ( 6149): Tried calling: position
I/flutter ( 6149):
I/flutter ( 6149): When the exception was thrown, this was the stack:
I/flutter ( 6149): #0 Object.noSuchMethod (dart:core-patch/object_patch.dart:53:5)
I/flutter ( 6149): #1 _FadingEdgeScrollViewState.initState. (package:fading_edge_scrollview/src/fading_edge_scrollview.dart:168:23)
I/flutter ( 6149): #2 SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:1113:15)
I/flutter ( 6149): #3 SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:1060:9)
I/flutter ( 6149): #4 SchedulerBinding._handleDrawFrame (package:flutter/src/scheduler/binding.dart:968:5)
I/flutter ( 6149): #8 _invoke (dart:ui/hooks.dart:261:10)
I/flutter ( 6149): #9 _drawFrame (dart:ui/hooks.dart:219:3)
I/flutter ( 6149): (elided 3 frames from dart:async)

I did not experience this exception when I was using the FadingEdgeScrollView without the TabBarView - so most likely this is an important factor to consider.

It may happen that content inside the scollable is too small.
In that case Flutter handle it quite well : Ripple effects are disabled along with scrolling.
But the fade stays.
How to hide the fade in that case ?

../../../Documents/flutter/.pub-cache/hosted/pub.dartlang.org/fading_edge_scrollview-2.0.1/lib/src/fading_edge_scrollview.dart:220:20: Warning: Operand of null-aware operation '?.' has type 'WidgetsBinding' which excludes null.

• 'WidgetsBinding' is from 'package:flutter/src/widgets/binding.dart' ('../../../Documents/flutter/packages/flutter/lib/src/widgets/binding.dart').
  WidgetsBinding.instance?.removeObserver(this);

This plugin calls .dispose() on the ScrollController argument it receives.

This means the obvious usage pattern is now wrong:

class _MyWidgetState extends State<MyWidget> {
  ScrollController _myController;

  @override
  void initState() {
    super.initState();
    _myController = ScrollController();
  }

  @override
  void dispose() {
    // Wrong, because this plugin wants me *not* to dispose my own controller!
    _myController.dispose();
    super.dispose();
  }

  @override
  Widget build() {
    return FadingEdgeScrollView.fromScrollView(child: ... _myController ...);
  }
}

This is surprising: If I'm supposed to create the controller and pass it in, it should also be my job to dispose it. This is the way it works everywhere else in Flutter.

So, I think you should not dispose the controller and let the user control its lifetime instead. This user ran into the same problem and would probably agree.

Thank you!

It would be nice if the fade at the bottom doesn't disappear so sudden.
Maybe it could smoothly disappear when you are scrolling towards the end / start of the list?

I was using the Marquee Package that depends on this package and I noticed that the pub.dev
shows the following error during the analysis issues.

ERROR: The argument type 'PageController?' can't be assigned to the parameter type 'ScrollController'.

When I ran my project using the marquee package, it sure enough, it showed an execution error.

Hi there! Subj. Or maybe there is some param for this feature?