https://github.com/phonegap/phonegap-plugin-barcodescanner/issues/418

ionic cordova platform rm android

ionic cordova platform rm ios

ionic cordova plugin rm phonegap-plugin-barcodescanner

rm -r plugins

rm -r node_modules

rm package-lock.json

Next remove the phonegap-plugin-barcodescanner of the package.json. Run:

npm install

ionic cordova platform add android

Next do a new build:

ionic cordova run android

Next add the plugin again:

ionic cordova plugin add phonegap-plugin-barcodescanner