In the top right corner of a standard KDE/Kubuntu installation you'll see this:
But seriously, I seem to be unable to understand what those "activities" are and what it would enable me to profit from. It just pops up like an "add widget" screen with just four options:
- New Activity - default plasma widgets desktop - is this a bug that it's called like that?
- Search and Launch - sort of over-spacious netbook interface?
- Photos Activity - I don't have any pictures local on my machine, useless for me.
- Desktop Icons - traditional style desktop-icons-only
Choosing one of those options seems to create a completely new desktop "plasma". Then why is this called Activity? Am I missing something?
Is this is nifty feature I've been missing on for a few years now or is this not that exciting? How do I use this as it's supposed to work?
Googling for what this is supposed to be give me all kind of vague descriptions like this one:
No feature defines the KDE 4 release series more than Activities. At the same time, no feature is so little understood -- Fedora even has a package for removing the desktop toolkit, which provides mouse access to Activities.
But, when you take the time to learn about Activities, you'll find them a natural extension of the desktop metaphor that just might help you to work more efficiently.
Activities are a super-set of Virtual Desktops. They don't replace Virtual Desktops -- in fact, each Activity can have its own set of Virtual Desktops if you choose. Instead, Activities are alternative desktops, each of which can have its own wallpaper, icons, and widgets.
Sorry, but after reading such a vague and impractical story I'm out. Can someone give me an overview of what I can do with it? I guess this is supposed to provide a way to separate private and business work, but then, how?
I had exactly the same issues and questions with "Activities" as you. I found the video Wicky posted to be instrumental in filling in gaps in my understanding of how Activities are suppose to improve upon traditional virtual desktops. The most important thing I took away from watching the video was that activities are just another type of virtual desktop that allow for more fine tuned control over your experience. Interesting examples of one or more features that could potentially be enabled in any activity are as follows:
Aside from power-settings, mouse clicks, and basic application restoration, I'm not sure any of these other features have yet been implemented. Indeed, my desire to figure this out came from someone else’s ask Ubuntu question where they were trying to write the app for language switching upon virtual desktop changes.
Overall I think the thing most holding back progress is a nice GUI tool to configure activities to execute commands or apps, and seems a likely next step.
This answer refers mainly to KDE4. For Plasma 5, see update at the end of answer.
Terminology is relative, but I guess the term "Activity" is used instead of "Desktop" because the latter is more commonly used on the one hand when referring to desktop environments, and on the other when referring to "virtual desktops" or "workspaces", while Activities are a way of using the plasticity and mobility of KDE.
What are Activities?
Each Activity is a set of virtual desktops (workspaces) with specific characteristics.
There are different types of activities.
(Not only you can create multiple ones and switch between them, but their characteristics can be very different, because they are of different types.)
What can I do with an Activity?
Before knowing what you can do with each type of activity it is useful to know what each activity can do.
The different characteristic of an Activity/set-of-workspaces that is already in place can be specified by clicking the last entry of the desktop menu (right-click on desktop) inside that Activity.
There you will see different types of activities, under Layouts:
In different systems they may be more or different
Changing the layout changes in fact the way an Activity operates.
Similar options can be set when creating a new Activity, only they are inconsistently called 'Templates':
That also may vary
There are some inconsistencies:
Some of them seem to serve basically the same purpose (which will reduce the number of "types" available - see below), others seem to serve no purpose at all :) - but there are a few that are interesting enough to make this discussion worthwhile. Some of them are just empty plasma desktops with some widgets added by default but some are more fundamentally different.
There is also an option called "Get new Templates" when creating a new Activity, which should give us more types of activities, but that doesn't work in the KDE system that I tested.
What can these types of activities do?
I'll try to describe each type of activity (and I'll try to update this answer on the way).
"Folder" layout/template (not different from "Desktop Icons") shows the content of
~./Desktopand thus allows icon files on the desktop. Sending an application to the desktop creates just an icon file for that instead of an icon widget (as is the case in the classic KDE desktop layout).The template "Search and launch" which seems to be the same as the layout called "Default Desktop" adds a very interesting feature: just by typing you can search and launch an application or search and find a file, bookmark, etc., without the need for clicking a search button on the panel or use a shortcut to open the search window. The search window pops up just by typing.
Not present by default in Kubuntu 14.04
"Group Desktop" has the option of creating groups, which look like empty widgets... What they are for I don't know yet.
"Grid Desktop" does the same as the previous, only it adds a grid on which the groups can be moved - but for what purpose I cannot say.
"Photo activity" is a classic KDE desktop that starts with two widgets (Photo Frame and Folders) showing the Pictures folder. Switching to this activity by shortcut will give easy access to your photos etc
"Newspaper layout" is (on my system) just an empty KDE desktop . It is just a name I guess with the idea of adding some widgets focused on news.
Summing up:
There can be many activities created at the same time, with different purposes, as the other answers explain.
But what I find interesting is to show the main types of activities that can be used and how they are different.
First, there are the widget-based activities: the classical KDE desktop layout (the one with icon-widgets, created by selecting "Empty desktop" for a new Activity) that can be by itself o good base for creating new specialized activities, by using specific widgets ("Photo activity" is an example).
Then, there are the three activities that have a different structure than the classical KDE layout+widgets. They all allow widgets too but add something more:
UPDATE on Plasma 5
In Kubuntu 15 the list of layouts contains only two entries:
~./DesktopThere are no Templates.
The default desktop has the "Search & launch" feature integrated.
In this episode of the Linux Action Show they explain the concept when they reviewed KDE 4.8, but it has been improved upon since then. Since I watched this and the video's on the Vivaldi tablet were released (check those out as well, they explain why it could be usefull to attach certain files or folders to an activity) I understood how to use them and couldn't switch from it. There are things that could be improbed upon are, as you already mentioned, that certain files which were open upon shutdown, or pausing of the activity, are not reopened when the activity is restarted. But it is very handy to be able to have different widgets on your desktop with different activities. That way your desktop doesn't get cluttered and you will get less distracted. That being said, it is only usefull when you do more than one of the same task where you need a specific setup often.
Even if proper answers were already been given I would try with a simple example: I use the same laptop for work and personal use. It is very distracting to have personal email, open tabs, programs, etc... around when you work and vice versa. At work I use a "work" activity where I have open my work email, browser with work tabs, programs and so on. When I go back home I click on "home" and, without losing anything, I have another laptop with my personal email opened, browser with my tabs, etc...
Think also about messages and notifications popping up when you are doing a presentation or in a screen-share call
The previous answer already explains it quite nicely. KDE has a feature where you can save all open windows. This means all windows will open again after a shut-down and restart, that were open/being used before. In conjunction with this feature then, it is nice if you can have a few different projects open, and you can continue working on them uninterrupted, just by switching an activity button on your desktop. Just like stated above, it is like having different projects on different workspaces/different screens. It is a great feature for multitaskers. You can, for example do your video editing on one activity screen, your bookkeeping for your business on another, and edit your journal or book on yet another virtual screen. Beware though, it takes some computing power. I think it is a nice feature for some people.
What you could do with it (if there was a frontend for nepomuk for that goal) is to track the time you spent on certain activities. Right now you would use a timetracker, which you would need to set manually or let it track the programs you used (which will give you a biiiig list after not too long - I tried). The information actually ist saved already, you just can't access and display it (yet).
Activities are like virtual machines, all running different instances of KDE Plasma, with different configurations, each configuration tailored for a different task.
Plus copy&paste between the virtual machines, not just of text but of entire applications!
Of course, Activities are more useful if your interactions with your computer are strongly compartmentalized, otherwise the effort to customize the different Activities leads simply to different looking desktops (not that that cannot be an end in itself…).