I'm trying to learn Flutter from a book that has been written before null safety, the code in it works perfectly if I add // @dart=2.9 at the beginning of the file, but gives some error without.
The error:
The argument type 'Object?' can't be assigned to the parameter type 'Map<String, dynamic>'.
Here is the code:
ListView.builder(
itemCount: latestComic,
itemBuilder: (context, i) => FutureBuilder(
future: _fetchComic(i),
builder: (context, comicResult) =>
comicResult.hasData ?
ComicTile(comic: comicResult.data) : // <- here gives the error when I remove
// @dart=2.9
Center(
child: Column(
children: [
Divider(
height: 40,
),
CircularProgressIndicator()
],
)
)
),
),
class ComicTile extends StatelessWidget {
final Map<String, dynamic> comic;
ComicTile({required this.comic});
@override
Widget build(BuildContext context) {
return ListTile(
leading: Image.network(
comic["img"],
height: 50,
width: 50,
),
title: Text(comic["title"]),
onTap: () {
Navigator.push(
context,
MaterialPageRoute(
builder: (BuildContext context) => ComicPage(comic: comic)
),
);
},
);
}
}
So I tried to change
builder: (context, comicResult)
to
builder: (context, AsyncSnapshot<Map>comicResult)
and now the error is:
The argument type 'Map<dynamic, dynamic>?' can't be assigned to the parameter type 'Map<String, dynamic>'.
Then I tried
builder: (context, AsyncSnapshot<Map<String, dynamic>>comicResult)
and now the error is:
The argument type 'Map<String, dynamic>?' can't be assigned to the parameter type 'Map<String, dynamic>'.
I tried to enter code here to solve passing parameters separately:
ComicTile(comicTitle: comicResult.data!["title"])
But I don't know how to pass images
How to pass Map<String, dynamic> to the ComicTile class?
