As you can see from my question, I am wondering which are the options to store data when creating application (let's say Android app, but also any other kind), other then using database and servers (SQL Server, Oracle, SQLite etc.)? Because when using this kind of storing data the user also has to be connected to the server and I don't want that.
Till now I met only with apps that store data in databases and if I have a TextBox where I input words that should later be shown in ComboBox those would always be followed with sql commands Insert into and after that Select from database to populate the ComboBox. But where should I Insert into and how can I do that if I want to store data on application user's mobile phone when deploying Android application?
If you don't want to use databases, try referring to this: How to store persistent data easily without using databases?
It is also mentioned in one of the answers above. But I would recommend you using Android Studio's SharedPreferences. Here are some links: https://developer.android.com/reference/android/content/SharedPreferences https://developer.android.com/training/data-storage/shared-preferences
Otherwise, offline storage options: What is the best way to store data offline on android apps?