I am used to Windows' taskmgr and Android list if running app to check the state of running apps. But, I am desperate to see an integral equivalent in Windows Phone or an app to do such job. Is it simply the case that Windows Phone doesn't allow this?
Officially, no, there's no such thing. There are a few reasons for this:
- WP apps can't see other apps (or indeed any process running outside the app's sandbox). This is by design, as a security measure to keep a malicious app from spying on you or interfering with other apps.
- WP automatically suspends backgrounded apps. If the phone runs low on memory, suspended apps are "dehydrated" (MSFT's term) to persistent storage and then removed entirely (this is part of why resuming an app sometimes takes a moment). There are only two kinds of apps that are allowed to run continuously in the background:
- Navigation apps (like Here Drive). Only one such app can run at a time; launching another will kill the first one. They can also only run in the background while using the GPS; they don't just automatically run in the background even when not being used.
- Streaming media apps (like Pandora). Unlike the navigation apps, the actual "app" still gets suspended or closed - the UI doesn't continue updating while in the background - but a separate process that drives the media content will keep running. Like navigation apps, only one such app can run at a time, and if another app starts to play audio the first one will exit.
- Given the above point, for most use cases, it's sufficient to simply see what apps are running / suspended. That's what you see when you press-and-hold on the Back button. Note that a media app might still be streaming but not located in this switcher, because the "actual app" part has exited and just the background streaming agent is still running.
Now, with all that said, there is a homebrew app available on the XDA-Developers forum that lists all running processes, including system ones. It's extremely slow - the way it works is to literally try every possible PID through a very slow (and basically unofficial) API - but if you want to see the list of processes it is possible. It doesn't have any control over the processes, though - the API gives basic read-only information and that's it - but it might be interesting.
In theory, hacks can be used to get more access. There are some restricted capabilities (not normally available to third-party developers) that might allow a task management app, but so far as I know nobody has written such a thing. On a fully rooted phone you could of course mess with processes however you liked, but there aren't any public "root" hacks for the OS yet.