What are some good resources to learn Android development?

The following reference is good for studying Android programming

Android Developers (Programming environment )

• https://developer.android.com/index.html
• https://developer.android.com/studio/index.html
• https://developer.android.com/studio/intro/index.html
• https://developer.android.com/training/basics/firstapp/index.html
• https://developer.android.com/samples/index.html