How to outline color an icon but that you can fill the color as well [Flutter]

Question

Hi what I want to do is make a stacked Icons type similar to this example for Text:

Stack(
                children: <Widget>[
                  Text(
                    widget.news.title,
                    style: TextStyle(
                      fontSize: 20,
                      foreground: Paint()
                        ..style = PaintingStyle.stroke
                        ..strokeWidth = 2
                        ..color = Colors.black,
                    ),
                  ),
                  Text(
                    widget.news.title,
                    style: TextStyle(
                      fontSize: 20,
                      color: Colors.white,
                    ),
                  ),
                ],
              ),

So what my goal is to have an amber colored fill with white outline for backarrow icon (added with SilverAppBar), but for now I was only able to access the iconTheme as follow:

iconTheme: IconThemeData(
                color: Colors.white,
              ),

So my question is as follow: How can I have back arrow icon with SilverAppBar colored that way

Output Image:

The Widget part code:

return <Widget>[
            SliverAppBar(
              pinned: true,
              expandedHeight: 200,
              title: Stack(
                children: <Widget>[
                  Text(
                    widget.news.title,
                    style: TextStyle(
                      fontSize: 20,
                      foreground: Paint()
                        ..style = PaintingStyle.stroke
                        ..strokeWidth = 2
                        ..color = Colors.black,
                    ),
                  ),
                  Text(
                    widget.news.title,
                    style: TextStyle(
                      fontSize: 20,
                      color: Colors.white,
                    ),
                  ),
                ],
              ),
              flexibleSpace: FlexibleSpaceBar(
                background: Image.network(
                  widget.news.urlToImage,
                  fit: BoxFit.fill,
                  errorBuilder: (context, error, StackTrace) {
                    return Image(
                      fit: BoxFit.cover,
                      image: AssetImage("images/placeholder_details.png"),
                    );
                  },
                ),
              ),
            )
          ];

Looking forward to hear your opinion :D

Answer 1

Tried out multiple solutions, and this works perfectly.

Use icon_decoration like this:

DecoratedIcon(
    icon: Icon(Icons.arrow_back, color: Colors.white),
    decoration: IconDecoration(border: IconBorder()),
)