Flutter gutter icons to not show for widgets inside conditional expressions

newer to flutter ans VS, in my mac it can show flutter icons when write code, but it can not show in left ...
I searched a lot of information but didn’t find the answer

flutter : Flutter 1.22.5 • channel stable
dart: 2.10.4 (stable)
VS: 1.54.1

Any suggestions are appreciated~~

I've not been able to repro this, the same icon shows up here:

If you paste the following simple code into your file somewhere, does it show there?

const a = const Icon(Icons.keyboard_arrow_up);

Does it not show up in any files or just some specific ones?

@DanTup

@DanTup
in my project it not show up in any files but it show correctly code is const a = const Icon(Icons.keyboard_arrow_up);

@PhoenixLeeSin

@PhoenixLeeSin are you able to trim your file down to something small you can share that still shows the problem? Perhaps with the same code I can reproduce it.

@DanTup

@DanTup oh.....when i init a new flutter project, icons shows in left!!!!

i do not konw why....

@PhoenixLeeSin

@PhoenixLeeSin can you try copying exactly the same code (ideally the whole file) into the small test project, and see if the same occurs there?

@DanTup

@DanTup thank u reply, when i copy the whole file it occurs error..
It’s a small mistake, but it does make me uncomfortable sometimes
whole file :

import 'package:flutter/material.dart';

class ScalableBox extends StatefulWidget {
  final List<Row> visibleSpans;
  final List<Row> unVisibleSpans;

  const ScalableBox({Key key, this.visibleSpans, this.unVisibleSpans})
      : super(key: key);
  @override
  _ScalableBoxState createState() => _ScalableBoxState();
}

class _ScalableBoxState extends State<ScalableBox> {
  bool _isMore = true;
  @override
  Widget build(BuildContext context) {
    return Container(
      padding: EdgeInsets.fromLTRB(10, 0, 0, 10),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: <Widget>[
          widget.visibleSpans.length >= 1
              ? widget.visibleSpans[0]
              : Container(),
          widget.visibleSpans.length >= 2
              ? widget.visibleSpans[1]
              : Container(),
          widget.visibleSpans.length >= 3
              ? widget.visibleSpans[2]
              : Container(),
          Offstage(
            offstage: _isMore,
            child: Column(
              children: widget.unVisibleSpans,
            ),
          ),
          widget.unVisibleSpans.length > 0
              ? Container(
                  child: GestureDetector(
                    onTap: () {
                      setState(() {
                        _isMore = !_isMore;
                      });
                    },
                    child: _isMore
                        ? Row(
                            mainAxisAlignment: MainAxisAlignment.center,
                            crossAxisAlignment: CrossAxisAlignment.center,
                            children: <Widget>[
                              Text(
                                '展开',
                                style: TextStyle(color: Colors.blue),
                              ),
                              Icon(
                                Icons.keyboard_arrow_down,
                                color: Colors.blue,
                                size: 16,
                              )
                            ],
                          )
                        : Row(
                            mainAxisAlignment: MainAxisAlignment.center,
                            crossAxisAlignment: CrossAxisAlignment.center,
                            children: <Widget>[
                              Text(
                                '收起',
                                style: TextStyle(
                                  color: Colors.blue,
                                ),
                              ),
                              Icon(
                                Icons.keyboard_arrow_up,
                                color: Colors.blue,
                                size: 16,
                              )
                            ],
                          ),
                  ),
                )
              : Container(),
        ],
      ),
    );
  }
}

@PhoenixLeeSin

@PhoenixLeeSin thanks! I was able to trim this down and it looks like it might be caused by the ternary operator:

I'll see if I can find a way to handle this. Thanks!

Thanks u Reply~

@bwilkerson

@bwilkerson this fails because I'm using the Flutter Outline data to locate icons, and for code with conditionals the then/else expressions are flat. This code:

return Container(
  child: true ? Icon(Icons.keyboard_arrow_down) : Container(),
);

Produces an outline like:

"children": [
	{
		"element": {
			"range": /*...*/,
			"name": "Icon(Icons.keyboard_arrow_down)",
			"kind": "CONSTRUCTOR_INVOCATION"
		},
		"range": /*...*/,
		"codeRange": /*...*/
	}
]

I had a look at handling this, and have a possible fix here (which supports conditionals both in child expressions and in widget lists):

https://dart-review.googlesource.com/c/sdk/+/192688/

Although I don't know if it's the correct/best fix. The conditional is not shown in the tree, so it looks a bit like a flat list even when some pair of the child nodes could be exclusive. Perhaps an additional node could be inserted, although it would add more to the tree (if/else in collections do not currently do that, they're just flattened, so this does match them).

WDYT?

I remember asking the question about if and for elements in the flutter outline when we were first implementing support for them, and I seem to remember that we decided to use a flat representation because we didn't have a good answer for the question of what to do when one branch would be represented in the outline and the other wouldn't.

I think that the solution in the referenced CL lgtm.

[analyzer] Include ConditionalExpressions in Flutter Outlines

This is fixed by dart-lang/sdk@387e9d9. The fix ships in the Dart SDK (not the VS Code extension), so will show up only once you're on a newer SDK that includes that change.

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Flutter gutter icons to not show for widgets inside conditional expressions #3196

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Flutter gutter icons to not show for widgets inside conditional expressions #3196

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DanTup commented on Mar 11, 2021

PhoenixLeeSin commented on Mar 12, 2021

DanTup commented on Mar 15, 2021

PhoenixLeeSin commented on Mar 16, 2021

DanTup commented on Mar 16, 2021

PhoenixLeeSin commented on Mar 17, 2021

DanTup commented on Mar 17, 2021

PhoenixLeeSin commented on Mar 18, 2021

DanTup commented on Mar 23, 2021

bwilkerson commented on Mar 23, 2021

DanTup commented on Mar 24, 2021

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