I am considering learning android development. I have some basic knowledge in C++. I downloaded the ADT plugin and eclipse. Now while starting from http://developers.android.com I see the codes were in XML. So I googled for learning XML. The best site I found was http://www.w3schools.org but there I found that for learning XML I have to learn HTML and CSS. So I learned the basics of HTML and CSS. But, Now I find in that learning java is a must.

So can someone give idea about the sequental languages that I should study now? Should I learn php,mysql too. BTW, I have a dream to work in google :p