Interface in a smartphone


Hi, it is my first topic in this forum. Sorry for my poor english.
BTW, i have a problem, i’m following a tutorial for develop a simple app and when i run the app in the browser, everything looks fine but if i run it in my cellphone the layout changes. The Header and the button looks wrong.
i’m running my app in a cellphone with sdk 16. Can that be the problem?

This is my app running in the browser:

And here is the app running in the cellphone: