Android applications are written in Java generally. (You can also go pure native by writing apps in C++, but one generally does not go there). With Java, it becomes cleaner and easier to use in my opinion.
So, to start out, you will need basics of Java. There are hundred and hundreds of resources online for you to learn Java. Simple google of "Java for beginners" will help. You can start here if you want to TheNewBoston - Java Beginner series.
https://www.youtube.com/watch?list=PLF ... l-zzrqQoSE
The layouts, how the app looks is written in XML. Basics of XML will do for starters. Nothing fancy about it. You can pick XML when you actually start with Android. So it kind of becomes optional.
Once you have got these two under your belt, you can move to Android. Again, you can find hundreds of resources online. Also, it is pretty huge topic and mastering it will take time. So my best is to dive straight into. Again you have TheNewBoston to the rescue with their video series here.
Some might say that it is not a good way to get started with as you miss out on many of the standards and practices, but I feel once you dive in and explore it by piece by piece and join all those pieces you will learn much more. Standard practices, memory optimizations, etc. will be much more appreciated if you do it the *wrong* way, get stuck and then understand the importance of doing it the *right* way.
These video series over here are good for beginners and help you start easily without being too intimidating. But always remember, that books and video series won't get you too far. You can start with these but if you really want to master it, after you finish getting the basics right, practice is the key.
1. Code every day!
2. Look at open source code, see how others build their apps, see how that other guy built that cool feature! (Github)
3. Refer these tutorials! These tutorials are your friend. They have all the info, what to use and how to use! (Android Development Tutorials and Courses)
4. Use StackOverflow https://stackoverflow.com/
Whenever you are stuck with certain piece of code, first use the documentation, if you can't solve it - Google it, still can't solve, use stackoverflow! 9/10 times the problem you are facing, must have been faced by someone else. See how the solved it! Don't just copy paste! See what you were doing wrong! Make a mental note of it!
Android is a vast topic! Don't expect to finish it in two weeks! It will take time. Perseverance is key!
All the best