charit.

[tight kelp]

Please be patient

Our volunteers look into many questions every day; sometimes it takes them a little while to answer.

Pro tip: you can rename the thread title with `.tr <thread name>`

Make it descriptive, including relevant context, but also to the point. This way you improve your chances of getting a more relevant and specific answer.

[tulip crest]

Yes, "sur" would be the usual translation.
Cette appli est diponible sur Android ?

However,

are you on your diet?
This is an idiomatic expression that doesn't translate literally in French. The corresponding phrase is "être au régime".
"Tu es au régime ?"

You aren't "on a diet" in French, you're "at the diet".

Similarly, you're not "on time", you're "at the time" (à l'heure).
So trying to find a general rule to translate prepositions is tricky business.