Flutter: Get the variable after the running of a function

Question

I'm having a problem getting a variable after the function runs.

I have to read a qr code and then put the qr code in a text field, but when i try to read it gets the default variable text, and only gets the right qr code when i try to read for the seccond time.

Here is the qr reader function:

  Future<void> scanQR() async {
    String barcodeScanRes;
    // Platform messages may fail, so we use a try/catch PlatformException.
    try {
      barcodeScanRes = await FlutterBarcodeScanner.scanBarcode(
          '#ff6666', 'Cancel', true, ScanMode.QR);
      print(barcodeScanRes);
    } on PlatformException {
      barcodeScanRes = 'Failed to get platform version.';
    }
    if (!mounted) return;

    setState(() {
      _scanBarcode = barcodeScanRes;
    });

  }

Here the button to run the function and then put the qr on the controller:

       onPressed: () {
                              scanQR();
                           
                                setState(() {
                                  _codprodController.text = _scanBarcode;
                                });                                                    
                            },
//on the first time i try it shows "unknown" that is the _scanBarCode default text instead of the qr i read

I guess the problem is the "_codprodController.text = _scanBarcode;" that its not runnig after (but together) the scanQR() but i dont know hot to fix.

Nilesh Senta · Accepted Answer · 2021-04-06 13:39:06Z

1

Try below

  onPressed: () async {
                              await scanQR();
                           
                                setState(() {
                                  _codprodController.text = _scanBarcode;
                                });                                                    
                            },

answered Apr 6, 2021 at 13:39

Nilesh Senta

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1 Comment

abrev Over a year ago

Oh, so easy, i just forgot it. Thanks!

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