can I make an app in my android mobile

Answer 1

yes ! use AIDE application it provides neccesary things to make android app in your smart phone

Answer 2

if you mean using your phone there is some sites but i dont think it is effective at all
if you mean develop an android apps learn java and then learn android api and use android studio or eclipse with android plugin to develop your apps
extra. you can learn c# and the use xamarin studio or visual studio with xamarin plugin to develop cross-platform applications
google it or look at Wikipedia