is it the same to say det or den in this case?
Yes, both work here, it depends on the gender of the thing you're speaking about, and without context it could be either.
What if the thing you are talking about is an action? Like swimming for example. That doesn't have a gender, does it?
Actions aren't things, grammatically speaking. They're strictly separated into nouns (things) and verbs (actions).
So if I wanted to say "I like it" (reffering to swimming) could I use both den and det?
Swedish always defaults to the neuter det for similar situations.
What is the difference between using gillar and tycker om? In media I usually see gillar.
There's no real difference in meaning but gillar is a little more colloquial. It is also what you do on FB.
Is "Det tycker om jag" acceptable?
Nope. It translates as something along the lines of "it likes I".
However, "det tycker jag om" works, the same way "that I like" does.
To be fair, "det tycker jag om" is a perfectly normal Swedish sentence. Generally, Swedish can move the object to the beginning of the sentence. However, we generally don't accept the shift in word order.
why is it om det? this confuses me
Tycker om is a particle verb (om should always be stressed). Read more here: https://www.duolingo.com/comment/5892480
Does it matter if I say 'det' or 'den'? Whats the differance?
Both work here since we don't know what the sentence is about. If you get a multiple choice question with both Jag tycker om den and Jag tycker om det, you need to check both too.
Why is it always den? Why cant it be det once in a while?
It's literally det in this specific sentence.
Which one is more common-ish? "gillar" or "tycker om"?
They're more or less interchangeable. I don't have a preference really. So you could use them just as much.
I did ask around and it seems like more people prefer "tycker om". But don't read too much into that, just use them interchangeably.
tack! that helps. I just wanted to learn Swedish pragmatically!
Can it be "Jag tycker det om"?
No, "tycker" and "om" belong together here.
But "tycker inte om" is correct, right?
Yes. The adverb goes right after the very verb in a main clause.
Why is it den and not det?
Either is fine without context.