Android - performance and accessibility - should know these

http://developer.android.com/guide/practices/design/performance.html

Android Using inner class as view in layout xml- classnotfoundexception

http://stackoverflow.com/questions/2098318/error-referencing-an-inner-class-view-in-layout-main-xml

Android Drag and Drop - Listview

https://github.com/commonsguy/cwac-touchlist

http://ericharlow.blogspot.com/2010/10/experience-android-drag-and-drop-list.html

Android disable gallery animated auto centering

Instead of setting onItemClickListener on the Gallery, set itemClickListener on each individual view(image)

High Level Android app fundamentals: Rookie/Novice/fresher...

http://developer.android.com/guide/topics/fundamentals.html - nothing better