Hello Adam,
I managed to reproduce the issue on Gigabyte Roma with Android 4.4.2. But it seems that you have implemented a lot of custom logic in your app and it works really slow. Could you please try to debug your app, this may help you to find the reason of the issue http://devcenter.appery.io/documentat...
Also could you please check the permissions:
http://en.miui.com/thread-38514-1-1.html
https://code.google.com/p/zxing/issue...
http://stackoverflow.com/questions/90...