Flutter QR how to pass QR data to the next screen - flutter

Question

How do I make it so when the user scan a QR code, the result will then be passed to the next screen.
Here is my code so far,
Widget build(BuildContext context) => SafeArea(
child: Scaffold(
body: Stack(
alignment: Alignment.center,
children: <Widget>[
buildQrView(context),
Positioned(top: 10, child: buildControlButtons()),
Positioned(bottom: 30, child: buildResult()),
],
),
),
The buildResult is this
Widget buildResult() => Container(
padding: EdgeInsets.all(12),
decoration: BoxDecoration(
borderRadius: BorderRadius.circular(8), color: Colors.white24),
child: Text(
barcode != null ? _dataFetch() : 'Scan a code!',
maxLines: 3,
),
Then the function _dataFetch is as below
_dataFetch() async {
if (barcode == null) {
print('error');
} else {
var route = new MaterialPageRoute(
builder: (BuildContext context) =>
new TransferProcessQR(
value: PassdataQR(
email: barcode!.code.toString(),
)
)
);
Navigator.of(context).push(route);
}
I have another class for PassdataQR but its pretty self explanatory. With this code everytime I run it will give me an error
The following _TypeError was thrown building QRScanPage(dirty, dependencies: [MediaQuery], state: _QRScanPageState#720ae):
type 'Future' is not a subtype of type 'String'
and the Navigator functions will be messed up.
Is there another approach I can do, so after a QR code is scanned, the result will be passed to the next screen without errors?

Answer 1

It seems to me that your _dataFetch method returns a futureand in your buildResult method you're using it like so:
Text(
barcode != null ? _dataFetch() : 'Scan a code!',
maxLines: 3,
)
You can use a futurebuilder to retrieve the async data:
Widget buildResult() => Container(
padding: EdgeInsets.all(12),
decoration: BoxDecoration(
borderRadius: BorderRadius.circular(8), color: Colors.white24),
child: FutureBuilder<string>(
future: _dataFetch,
builder: (BuildContext context, AsyncSnapshot<String> snapshot) {
if (snapshot.HasData) {
return Text(snapshot.data, maxLines: 3);
} else return Text('Scan a code!', maxLines: 3);
},
),
);

Answer 2

According to your repository you could just modify line 150:
controller.scannedDataStream
.listen((barcode) => {
setState(() => this.barcode = barcode));
Get.to(new TransferProcessQR(
value: PassdataQR(
email: barcode!.code.toString(),
)
));
}
Notice that in order for this to work you'll have to use the Get Package Route Management to navigate to another page. That's because you don't have access to the build context in this code snipped. Normally you would call Navigator.of(context).push(...) but that's not possible without a build context.