In the "lists" section, I can't change the Clock to the Anchor under the List Buttons header.

1. Clock on the down arrow.
2. See the menu appear.
3. Click on the Anchor.
4. Nothing happens.

Expected behavior: The menu closes and I see the Anchor displayed in the button.

Actual behavior: The menu remains open. If I click away, the Clock is still selected.

The same thing happens with the Basic and Color example List Buttons.

cace42525049b6c6473a7b579de440be66df0221 introduced the a bug in TextInput that manifests as the following exception:

Tried to make a child into a parent of itself.
'package:flutter/src/widgets/focus_manager.dart':
Failed assertion: line 1041 pos 12: 'child != this'

I hope my layout is fine in the example - I've still got to work on figuring that out for myself.

I also noticed that Ink widgets were present in the implementation of Tab/TabPane without any Material to paint on, so I replaced those with DecoratedBox widgets. There are certainly other solutions to achieve the same effect but this is the most lightweight one that I've found.

They served to enforce that the caller can't set the selection to an out-of-bounds index based on an attached list view, but that's notnecessary at all -- the caller just sets selected ranges, and if those ranges are outside the bounds of the actual list content, there's no inherent harm in that; it's the caller's business.

The only non-assert usage of attach/detach was the selectAll() API method, but that API's not needed either, since the caller knows their data model and can just set the desired range.

Fixes #14

Hi Todd,

Awesome talk and what a great library.

You might want to point out somewhere what the minimum required version of Flutter for this repo is. I did try the current latest stable (2.2.0), but then there were a lot of errors like: ../lib/src/scroll_bar.dart:826:29: Error: Type 'LongPressDownDetails' not found.

Switching to 2.3.0-1.0.pre solved it for me.

Regards, Sander

Since https://github.com/flutter/flutter/pull/85798, Rollup is triggering the following assertion:

======== Exception caught by rendering library =====================================================
The following assertion was thrown during paint():
Attempted to create a handle to an already disposed layer: ClipRectLayer#2aefa(handles: 0, clipRect: Rect.fromLTRB(6.0, 22.0, 699.0, 242.0), clipBehavior: Clip.hardEdge).
'package:flutter/src/rendering/layer.dart':
Failed assertion: line 620 pos 7: 'layer?.debugDisposed != true'


Either the assertion indicates an error in the framework itself, or we should provide substantially more information in this error message to help you determine and fix the underlying cause.
In either case, please report this assertion by filing a bug on GitHub:
  https://github.com/flutter/flutter/issues/new?template=2_bug.md

The relevant error-causing widget was: 
  _RevealBox _RevealBox:file:///Users/tvolkert/project/tvolkert/chicago/lib/src/rollup.dart:204:11
When the exception was thrown, this was the stack: 
#2      LayerHandle.layer= (package:flutter/src/rendering/layer.dart:620:7)
#3      ContainerLayer.append (package:flutter/src/rendering/layer.dart:1042:25)
#4      PaintingContext.appendLayer (package:flutter/src/rendering/object.dart:237:21)
#5      PaintingContext.pushLayer (package:flutter/src/rendering/object.dart:395:5)
#6      PaintingContext.pushClipRect (package:flutter/src/rendering/object.dart:454:7)
#7      _RenderRevealBox.paint (package:chicago/src/rollup.dart:278:30)
#8      RenderObject._paintWithContext (package:flutter/src/rendering/object.dart:2409:7)
#9      PaintingContext.paintChild (package:flutter/src/rendering/object.dart:189:13)
#10     RenderBoxContainerDefaultsMixin.defaultPaint (package:flutter/src/rendering/box.dart:2794:15)
#11     RenderFlex.paint (package:flutter/src/rendering/flex.dart:1078:7)
#12     RenderObject._paintWithContext (package:flutter/src/rendering/object.dart:2409:7)
#13     PaintingContext.paintChild (package:flutter/src/rendering/object.dart:189:13)
#14     RenderBoxPane.paint (package:chicago/src/box_pane.dart:349:17)
#15     RenderObject._paintWithContext (package:flutter/src/rendering/object.dart:2409:7)
#16     PaintingContext.paintChild (package:flutter/src/rendering/object.dart:189:13)
#17     RenderScrollPane._paintChildren.<anonymous closure> (package:chicago/src/scroll_pane.dart:1769:19)
#18     ClipContext._clipAndPaint (package:flutter/src/painting/clip.dart:30:12)
#19     ClipContext.clipRectAndPaint (package:flutter/src/painting/clip.dart:58:5)
#20     RenderScrollPane._paintChildren (package:chicago/src/scroll_pane.dart:1768:17)
#21     PaintingContext.pushLayer (package:flutter/src/rendering/object.dart:398:12)
#22     PaintingContext.pushClipRect (package:flutter/src/rendering/object.dart:454:7)
#23     RenderScrollPane.paint (package:chicago/src/scroll_pane.dart:1748:13)
#24     RenderObject._paintWithContext (package:flutter/src/rendering/object.dart:2409:7)
#25     PaintingContext._repaintCompositedChild (package:flutter/src/rendering/object.dart:141:11)
#26     PaintingContext.repaintCompositedChild (package:flutter/src/rendering/object.dart:100:5)
#27     PipelineOwner.flushPaint (package:flutter/src/rendering/object.dart:979:29)
#28     RendererBinding.drawFrame (package:flutter/src/rendering/binding.dart:455:19)
#29     WidgetsBinding.drawFrame (package:flutter/src/widgets/binding.dart:883:13)
#30     RendererBinding._handlePersistentFrameCallback (package:flutter/src/rendering/binding.dart:319:5)
#31     SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:1143:15)
#32     SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:1080:9)
#33     SchedulerBinding._handleDrawFrame (package:flutter/src/scheduler/binding.dart:996:5)
#37     _invoke (dart:ui/hooks.dart:164:10)
#38     PlatformDispatcher._drawFrame (dart:ui/platform_dispatcher.dart:262:5)
#39     _drawFrame (dart:ui/hooks.dart:127:31)
(elided 5 frames from class _AssertionError and dart:async)
The following RenderObject was being processed when the exception was fired: _RenderRevealBox#9f570 relayoutBoundary=up3
...  needs compositing
...  parentData: offset=Offset(0.0, 16.0); flex=null; fit=null (can use size)
...  constraints: BoxConstraints(unconstrained)
...  size: Size(693.0, 220.0)
RenderObject: _RenderRevealBox#9f570 relayoutBoundary=up3
  needs compositing
  parentData: offset=Offset(0.0, 16.0); flex=null; fit=null (can use size)
  constraints: BoxConstraints(unconstrained)
  size: Size(693.0, 220.0)
...  child: RenderPadding#1aac6 relayoutBoundary=up4 NEEDS-PAINT
...    needs compositing
...    parentData: <none> (can use size)
...    constraints: BoxConstraints(unconstrained)
...    size: Size(693.0, 220.0)
...    padding: EdgeInsets(0.0, 4.0, 0.0, 0.0)
...    textDirection: ltr
...    child: RenderFlex#69cd9 relayoutBoundary=up5 NEEDS-PAINT
...      needs compositing
...      parentData: offset=Offset(0.0, 4.0) (can use size)
...      constraints: BoxConstraints(unconstrained)
...      size: Size(693.0, 216.0)
...      direction: horizontal
...      mainAxisAlignment: start
...      mainAxisSize: min
...      crossAxisAlignment: center
...      textDirection: ltr
...      verticalDirection: down
...      child 1: RenderConstrainedBox#3eff2 relayoutBoundary=up6
...        parentData: offset=Offset(0.0, 108.0); flex=null; fit=null (can use size)
...        constraints: BoxConstraints(unconstrained)
...        size: Size(7.0, 0.0)
...        additionalConstraints: BoxConstraints(w=7.0, 0.0<=h<=Infinity)
...      child 2: RenderConstrainedBox#0cbdb relayoutBoundary=up6
...        parentData: offset=Offset(7.0, 108.0); flex=null; fit=null (can use size)
...        constraints: BoxConstraints(unconstrained)
...        size: Size(4.0, 0.0)
...        additionalConstraints: BoxConstraints(w=4.0, 0.0<=h<=Infinity)
...      child 3: RenderFlex#fc552 relayoutBoundary=up6 NEEDS-PAINT
...        needs compositing
...        parentData: offset=Offset(11.0, 0.0); flex=null; fit=null (can use size)
...        constraints: BoxConstraints(unconstrained)
...        size: Size(682.0, 216.0)
...        direction: horizontal
...        mainAxisAlignment: start
...        mainAxisSize: max
...        crossAxisAlignment: start
...        textDirection: ltr
...        verticalDirection: down
...        child 1: _RenderBorderLayout#0707b relayoutBoundary=up7 NEEDS-PAINT
...          needs compositing
...          parentData: offset=Offset(0.0, 0.0); flex=null; fit=null (can use size)
...          constraints: BoxConstraints(unconstrained)
...          size: Size(188.0, 180.0)
...        child 2: RenderConstrainedBox#49a52 relayoutBoundary=up7
...          parentData: offset=Offset(188.0, 0.0); flex=null; fit=null (can use size)
...          constraints: BoxConstraints(unconstrained)
...          size: Size(4.0, 0.0)
...          additionalConstraints: BoxConstraints(w=4.0, 0.0<=h<=Infinity)
...        child 3: _RenderBorderLayout#6a2c1 relayoutBoundary=up7
...          needs compositing
...          parentData: offset=Offset(192.0, 0.0); flex=null; fit=null (can use size)
...          constraints: BoxConstraints(unconstrained)
...          size: Size(165.0, 130.0)
...        child 4: RenderConstrainedBox#49e6f relayoutBoundary=up7
...          parentData: offset=Offset(357.0, 0.0); flex=null; fit=null (can use size)
...          constraints: BoxConstraints(unconstrained)
...          size: Size(4.0, 0.0)
...          additionalConstraints: BoxConstraints(w=4.0, 0.0<=h<=Infinity)
...        child 5: _RenderBorderLayout#f4143 relayoutBoundary=up7
...          needs compositing
...          parentData: offset=Offset(361.0, 0.0); flex=null; fit=null (can use size)
...          constraints: BoxConstraints(unconstrained)
...          size: Size(171.0, 216.0)
...        child 6: RenderConstrainedBox#fa98f relayoutBoundary=up7
...          parentData: offset=Offset(532.0, 0.0); flex=null; fit=null (can use size)
...          constraints: BoxConstraints(unconstrained)
...          size: Size(4.0, 0.0)
...          additionalConstraints: BoxConstraints(w=4.0, 0.0<=h<=Infinity)
...        child 7: _RenderBorderLayout#e2686 relayoutBoundary=up7
...          needs compositing
...          parentData: offset=Offset(536.0, 0.0); flex=null; fit=null (can use size)
...          constraints: BoxConstraints(unconstrained)
...          size: Size(146.0, 134.0)
====================================================================================================

Observed at 14b1e5ec34524ac527dce1ac4d23db6355487f1c

I have a list of items that can be selected or not. It affects many aspects of the app. There's a ListView that's used to configure that list of items, so I use a ListViewSelectionController as the source of truth. Unfortunately that ListView isn't always on screen, so sometimes it's not attached, and ListViewSelectionController.isItemSelected asserts that it is attached. So I can't use the ListViewSelectionController as the source of truth.

Side note: it would be great if ListViewSelectionController had an affordance to enumerate the selected items. Currently I have to just loop over the items one by one querying if they're selected, and that seems expensive given how the list is backed.

ListViewSelectionController will send notifications any time any of its mutation affordances are invoked, even if the net result does not involve changing anything about the selection.

Render objects should not subscribe to anything until they are attached, and should unsubscribe from things when they are detached. RenderListView subscribes when the selectionController property is set, and never unsubscribes.

This means that if you have a ListView that uses a controller, and then you remove it from the rendering, and give the controller to something else, then when the controller changes value, that original ListView will try to dirty itself and throw an exception (because it's disposed and thus should not be mutating itself any more).

Hey Todd, I want to use chicago in an upcoming talk about Flutter for Desktop, so I thought I'd update it for Flutter 3.

Ping me if you have any questions!

If I tab through https://tvolkert.github.io/ I never get to the list boxes.

In general, tabbing through https://tvolkert.github.io/, I don't get to the check boxes, the link buttons, any of the widgets under "Lists", half of the widgets in the calendar section, up and down arrows down move between radio buttons, and nothing in the Tables section ends up getting focus.