Reading the contents of a file into a String variable in Flutter - flutter

Question

The problem is this: I have a .txt file that contains one line of text and I need to read that line into a String variable.
Most of the methods I found return either a Future or Future and I have no idea how to convert these types into Strings. Also, I'm not sure what I'm doing wrong with readAsStringSync because I get a "FileSystemExeption: Cannot open file (OS Error: No such file or directory)", even though I have referenced it in my pubspec.yaml
class LessonPage extends StatelessWidget { LessonPage({this.title, this.appBarColor, this.barTitleColor, this.fileName});
final String title;
final Color appBarColor;
final Color barTitleColor;
final String fileName;
#override
Widget build(BuildContext context) {
final file = new File(this.fileName);
return new Scaffold(
appBar: new AppBar(
title: new Text(
this.title,
style: new TextStyle(color: this.barTitleColor)
),
backgroundColor: this.appBarColor,
),
body: new Center(
child: new Text(
file.readAsStringSync(),
softWrap: true,
)
),
);

Answer 1

Embrace Futures! This use case is exactly what FutureBuilder was made for.
To read assets as strings, you don't need to construct a File. Instead, use DefaultAssetBundle to access asset files. Make sure that the asset file you want to read is declared in pubspec.yaml.
return new Scaffold(
appBar: new AppBar(
title: new Text(
this.title,
style: new TextStyle(color: this.barTitleColor)
),
backgroundColor: this.appBarColor,
),
body: new Center(
child: new FutureBuilder(
future: DefaultAssetBundle.of(context).loadString(fileName),
builder: (context, snapshot) {
return new Text(snapshot.data ?? '', softWrap: true);
}
),
),
);
If you're reading a file that isn't an asset (for example, a file you downloaded to a temporary folder) then it's appropriate to use a File. In that case, make sure that the path is correct. Consider using FutureBuilder instead of the synchronous File APIs, for better performance.