It takes lots of time and sometimes QRCode is not getting scanned

[sana080]

Description of the problem:

I am using for scanning QRCode but it is not getting scanned and when it is then it takes lots of time

Which library version are you using? 3.5.2

**Which phone/tablet are you using, and which Android version does it run?
. Moto G, Android 5.1

Does the same happen on other devices or an emulator?
Tested in MotoG and Samsung J2

[Adikso]

I am also having this problem on Nexus 5, Android 6.0

[deathnopool]

having the same problem on android n

[Nerkritus]

Also experiencing this on Motorola G Play, Android 6.0.1

Library version 3.5.0.

[aitbaali]

any solution @journeyapps?

[rkistner]

@aitbaali No solution yet. Could be related to the target SDK version of the app, but haven't confirmed yet.

[Nerkritus]

@rkistner I'm targeting Marshmallow (23) in my app with minimum SDK set to Kit Kat (19).

I also recently installed the Feb 2017 security patches if that helps.

[pawelantczak]

Same with targetSdkVersion 25

[eligiobz]

Same problems on Samsung J7 and targetSdkVersion 23

[Nerkritus]

I've noticed this is only affecting my app in debug. When I run the release from the play store on the problem device, QR code scanning works fine.

So perhaps it's not such a big deal.

[letitfly]

+1 same here. Android 5.1, HTC One.

[sana080]

@Nerkrotus : Agree
Working comparatively better and fast when not running in debug mode

[aitbaali]

It worked fast and better for me when I change the size of the barcodeview to a small size (in my case: W500 & H300 on a tablet) and turn the torch on.

barcodeScanner is an instance if DecoratedBarcodeView
barcodeScanner.getBarcodeView().setFramingRectSize(new Size(width, height));

if (hasFlash()) {
            barcodeScannerFid.setTorchOn();
}

 /**
     * Check if the device's camera has a Flashlight.
     *
     * @return true if there is Flashlight, otherwise false.
     */
    private boolean hasFlash() {
        return getApplicationContext().getPackageManager()
                .hasSystemFeature(PackageManager.FEATURE_CAMERA_FLASH);
    }

see https://github.com/journeyapps/zxing-android-embedded/blob/50e3acce091decc195f67e6079b86427ddc2ad60/sample/src/main/java/example/zxing/CustomScannerActivity.java

[ismdcf]

Had the same issue when trying to give a custom random size and then figured out the aspect ratio plays a major role in the qr code readability.

Following size worked for me
240dp height
320dp width

and if setting the value to a larger screen size multiplying the value by integer gave good readability.
480dp height
640dp width

[xxss0903]

before Detector to detect the QRCode bitmatrix, i found if bitmatrix.rotate180() can improve the scan effective.

[rkistner]

Debugger mode will make scanning slower - always test performance without a debugger connected.

For the other reports here there is not enough info to debug.