Thumbs not rendering - Flutter 1.20

pastordougdev commented 4 years ago

I am just beginning to work with the RangeSlider widget. When trying to render a simple RangeSlider, encountering the following:

══╡ EXCEPTION CAUGHT BY RENDERING LIBRARY ╞═════════════════════════════════════════════════════════
The following NoSuchMethodError was thrown during paint():
The getter 'isEmpty' was called on null.
Receiver: null
Tried calling: isEmpty

When the exception was thrown, this was the stack:
#0      Object.noSuchMethod (dart:core-patch/object_patch.dart:51:5)
#1      RoundSliderThumbShape.paint (package:flutter/src/material/slider_theme.dart:2395:30)
#2      _RenderRangeSlider._paintThumbs (package:flutter_range_slider/src/flutter_range_slider.dart:1043:29)
#3      _RenderRangeSlider.paint (package:flutter_range_slider/src/flutter_range_slider.dart:914:5)
#4      RenderObject._paintWithContext (package:flutter/src/rendering/object.dart:2266:7)
#5      PaintingContext.paintChild (package:flutter/src/rendering/object.dart:186:13)
#6      RenderShiftedBox.paint (package:flutter/src/rendering/shifted_box.dart:72:15)
#7      RenderObject._paintWithContext (package:flutter/src/rendering/object.dart:2266:7)
#8      PaintingContext.paintChild (package:flutter/src/rendering/object.dart:186:13)
#9      RenderBoxContainerDefaultsMixin.defaultPaint (package:flutter/src/rendering/box.dart:2525:15)
#10     RenderFlex.paint (package:flutter/src/rendering/flex.dart:969:7)
#11     RenderObject._paintWithContext (package:flutter/src/rendering/object.dart:2266:7)
#12     PaintingContext.paintChild (package:flutter/src/rendering/object.dart:186:13)
#13     RenderBoxContainerDefaultsMixin.defaultPaint (package:flutter/src/rendering/box.dart:2525:15)
#14     RenderCustomMultiChildLayoutBox.paint (package:flutter/src/rendering/custom_layout.dart:406:5)
#15     RenderObject._paintWithContext (package:flutter/src/rendering/object.dart:2266:7)
#16     PaintingContext.paintChild (package:flutter/src/rendering/object.dart:186:13)
#17     RenderProxyBoxMixin.paint (package:flutter/src/rendering/proxy_box.dart:133:15)
#18     _RenderInkFeatures.paint (package:flutter/src/material/material.dart:533:11)
#19     RenderObject._paintWithContext (package:flutter/src/rendering/object.dart:2266:7)
#20     PaintingContext.paintChild (package:flutter/src/rendering/object.dart:186:13)
#21     RenderProxyBoxMixin.paint (package:flutter/src/rendering/proxy_box.dart:133:15)
#22     PaintingContext.pushLayer (package:flutter/src/rendering/object.dart:393:12)
#23     RenderPhysicalModel.paint (package:flutter/src/rendering/proxy_box.dart:1821:15)
#24     RenderObject._paintWithContext (package:flutter/src/rendering/object.dart:2266:7)
#25     PaintingContext.paintChild (package:flutter/src/rendering/object.dart:186:13)
#26     RenderProxyBoxMixin.paint (package:flutter/src/rendering/proxy_box.dart:133:15)
#27     RenderObject._paintWithContext (package:flutter/src/rendering/object.dart:2266:7)
#28     PaintingContext.paintChild (package:flutter/src/rendering/object.dart:186:13)
#29     RenderProxyBoxMixin.paint (package:flutter/src/rendering/proxy_box.dart:133:15)
#30     RenderObject._paintWithContext (package:flutter/src/rendering/object.dart:2266:7)
#31     PaintingContext._repaintCompositedChild (package:flutter/src/rendering/object.dart:137:11)
#32     PaintingContext.repaintCompositedChild (package:flutter/src/rendering/object.dart:97:5)
#33     PipelineOwner.flushPaint (package:flutter/src/rendering/object.dart:982:29)
#34     RendererBinding.drawFrame (package:flutter/src/rendering/binding.dart:406:19)
#35     WidgetsBinding.drawFrame (package:flutter/src/widgets/binding.dart:867:13)
#36     RendererBinding._handlePersistentFrameCallback (package:flutter/src/rendering/binding.dart:286:5)
#37     SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:1117:15)
#38     SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:1056:9)
#39     SchedulerBinding.scheduleWarmUpFrame.<anonymous closure> (package:flutter/src/scheduler/binding.dart:865:7)
(elided 4 frames from class _RawReceivePortImpl, class _Timer, and dart:async-patch)

The following RenderObject was being processed when the exception was fired: _RenderRangeSlider#32f2f:
  creator: _RangeSliderRenderObjectWidget ← RangeSlider ← SliderTheme ← Padding ← Container ← Column ←
    _BodyBuilder ← MediaQuery ← LayoutId-[<_ScaffoldSlot.body>] ← CustomMultiChildLayout ←
    AnimatedBuilder ← DefaultTextStyle ← ⋯
  parentData: offset=Offset(20.0, 20.0) (can use size)
  constraints: BoxConstraints(0.0<=w<=374.0, 0.0<=h<=Infinity)
  size: Size(374.0, 32.0)
This RenderObject has no descendants.

In RoundSliderThumbShape.paint, it is expecting an argument of type Size called sizeWithOverflow which is not being passed.