Adjust view based on mobile device

We have an mobile app that we have distributed to our customers for use in the field with their techs. The app was created/designed using a older Android mobile phone and turned out great. I recently visited one of my customers and talked with their techs and most of the techs had different mobile devices with different screen sizes and our app looked awkward on some of their devices, meaning not centered and clean looking.

App functioned as expected on all devices, but the look wasn’t clean. With all different screens these mobile phones are coming with, I like to be able to have the app auto adjust for the different screen sizes on the mobile devices. Basically zoom in / out based on screen size.

Is this possible ? Just a fyi, we have our app set to “full width”

Any and all help would be appreciated…