[quantummkv]

>I used activities instead of fragments. I had the feeling that the fragment was not the best option because the navigation plan can be too complex. am I right?

> When choosing the products, I used only a single activity and used code to change the design of the activity. I thought it that can be faster than using many activities and keep the download size smaller. Does it make sense?

This is where fragments come into picture. You break up parts of your UI in fragments then swap then in and out of your activities. You can also use multiple fragments to compose the UI in an activity.

A good way to think of this is to consider an activity as a Room. All the various tables, furniture, etc inside the room become fragments that you can move in and out of rooms according to your need. To extend this analogy a bit more, you can use multiple activities to separate the various logical parts of your app. Similar to how an apartment has many rooms, with each room having a separate function.

Btw, This is the kind of thing that got me into programming as a kid. An excellent use of technology to solve a personal pain point in a traditional business. Keep working on it.

[maherdeeb]

Your illustration about activity vs fragment is awesome. I wish I knew this before. Thank you very much!