How does gnome-app-install decides which packages are listed and which are not?

Depending on your selection for "Show:" your what you put into "Search:" and what category you select on the left.

There are still some packages that don't show up there because they don't have actually an entry into your applications menu.

Usually there are only programs that have a graphical user interface (GUI). If you want to install other applications or basically all you can on ubuntu you should consider using "synaptics" (menu: System->Administration->Synaptic Package Manager) or the command line tool apt (commands: "apt-get", "apt-cache" and so on).

I think it is as well influenced by the selections you make in System->Administration->Software Sources

Hope this solves your question.

You don't understand me...

I want to obtain the full package list used by gnome-app-install, therefore, I need:
1. The way gnome-app-install obtain the full package list
And/Or
2. The list itself

I prefer the second way, since it will ease my work.

I browsed the source of gnome-app-install and found out that it uses ArchiveCrawler (bzr branch lp:~mvo/archive-crawler/mvo).
I able to produce a list of packages which seems to be the ones which are in use by gnome-app-install, but I am not sure it is the full list.

Any help appreciated!

Sorry, but for me it is still not clear why you need that.

The package managers of Ubuntu use as far as I can see the files in /var/lib/apt/lists.
Certainly some packages listed in those files do not show up in gnome-app-install for reasons I gave before.

Hope this helps.

I am building some program which needs the packages displayed by gnome-app-install since those packages are packages which has GUI etc...

Thanks!

Thanks Jo-Erlend Schinstad, that solved my question.