There are quite a few iOS sightsinging apps - one is called Sight Sing Pro. You can cover the screen and notate what your hear rather than singing it. People also go on about an app called functional ear trainer, which is supposed to be revolutionary in that it is based on the idea that you relate everything to a scale and count up from the bottom to find the lower notes, or down from the top to find the higher notes. How that is revolutionary is totally beyond me, but of course it works.
Hearing where a note belongs in a scale is not the same thing as hearing the interval from the previous note and working it out that way. If dictation is your focus, I would avoid any apps that train interval recognition. I am not saying that is not a worthwhile skill, just to be clear, but I don't think it's the best single tool for this particular job.