What will be better choice Android app development or i-os development???

Answer 1

Depends on where your passion lies within. I'd certainly go for Android though, pushing an iOS application to AppStore seems like a relatively hard labor, from what I've seen.

Answer 2

android developer- $25 one time payment
iOS developer - $100 a year.
if money isn't a worry for you, I would go for both. iOS users pretty much stay with iOS and both platforms have their followers. if you want to reach more ppl, learn to develop for both.

c# works for both as a basis to get started. you'll have to look into specific permissions and parameters for each platform as well as native design and responsiveness on different screen sizes.