Android is a mobile operating system developed by Google, based on the Linux kernel and designed primarily for touchscreen mobile devices such as smartphones and tablets.
Following are some good content links on Android.
Android SQLite Database Example- Provides code samples and explanation about using SQLite Database in Android
Android BroadCastReceiver Tutorial- Android BroadCastReceiver Tutorial
Create Custom Adapter List in Android- This article is about how to create custom adapters for list view in android. It also explains about how to optimize list view using ViewHolder pattern in android. It also discusses about array adapter, cursor adapter.
Android Asynctask Example- This tutorial is about asynctask in android. Here we will be developing an app using asynctask that performs abstract asynctask in background.We will be also discussing about different concepts involved in using asynctask in android.
Android Service Example- This tutorial explains about different android services such as bounded,unbounded,intentservice with examples. It also describes ways to create and implement different android services with code samples.