Error while scanning sometimes on android

[tmfelwu]

On android, sometimes, when the code is scanned the scanner doesnt close and if u continue scanning after scan that the scanner closes with {text:"", cancelled: true}

[kbytesys]

It happend also to me in my samsung s3 mini.

The first scan works fine, then the scanner scan the code twice and returns {text:"", cancelled: true}

[kbytesys]

I made an interesting test:

$scope.scanBarcode = function() {
    alert("With this alert, the scan will work");

    $cordovaBarcodeScanner.scan().then(function(imageData) {
      alert(imageData.text);
      console.log("Barcode Format -> " + imageData.format);
      console.log("Cancelled -> " + imageData.cancelled);
    }, function(error) {
      alert(error);
      console.log("An error happened -> " + error);
    });
  };

It's a bit weird, but the scan works. This doesn't solve the issue, but can help to find what's wrong.

[tmfelwu]

Yeah i think the js code is fine, something probably wrong with the java code here I think this test resultCode == Activity.RESULT_OK is failing and this.callbackContext.error("Unexpected error"); is being called. I have no idea where to go from here. I would be happy if it atleast gives the correct result after second scan. Idk java @kbytesys can u look into it.

[kbytesys]

That java code doesn't explain why the barcode reader tries to scan twice.

I think there are some bug in the activation of the cordova plugin or in the zxing library installed in some phones, but I'm unable to debug this issue atm :(

Maybe some official dev could try to recreate the bug or just release the plugin with some extra debug log info 😸

[tmfelwu]

given the amount of activity here that will be a long time

[kbytesys]

Maybe this issue could be related

#124

[kbytesys]

@sparshy please, you can try if my fork submitted in the pr solves your problem?

https://github.com/kbytesys/phonegap-plugin-barcodescanner/tree/android-zxing-integration

[tmfelwu]

@kbytesys No still the same error, is it working for you?

[kbytesys]

@sparshy yep

did you removed the old plugin and added mine with

cordova plugin add https://github.com/kbytesys/phonegap-plugin-barcodescanner.git#android-zxing-integration

?

[fonini]

Wrapping the plugin call with a setTimeout also works.

[tmfelwu]

@fonini can you elaborate

@kbytesys yes i did install ur plugin

[fonini]

@sparshy I've used the $timeout from Ionic/Angular

$timeout(function(){
    cordova.plugins.barcodeScanner.scan(
      function (result) {
          alert("We got a barcode\n" +
                "Result: " + result.text + "\n" +
                "Format: " + result.format + "\n" +
                "Cancelled: " + result.cancelled);
      }, 
      function (error) {
          alert("Scanning failed: " + error);
      }
   );
});

But I guess you can use a simple setTimeout instead the $timeout.

[koga73]

@fonini Wrapping in a $timeout worked for me. Do you have any idea what the issue is and why this would fix it?

[fonini]

@koga73 Unfortunately, I have no idea why.

[koga73]

I've noticed when it is going to "fail" the barcode scanner almost appears to open twice. Any scanning after and it fails. The timeout works most of the time but I still saw it fail once or twice. I added a 100ms delay to the timeout and it seems to be better now.

[koga73]

Update: This is the same as issue #38
Change "ng-click" to "on-touch". This also explains why the timeout was somewhat effective.

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