Static .json files do not load while running on smartphone

I have the following files in the “…/assets/strings/” directory of my Ionic application:


When I run my application in the browser, with the “ionic serve” command, these files are perfectly accessed.

However, when I run on the smartphone with the “ionic cordova run android” command, .json files are not copied to the “android_asset / www” directory, and therefore are not accessed in the application that is running on the smartphone. Causing the following error:


Any tip will be very welcome, as I have already lost a few hours with this problem.