Research: Design For Android

Design Principle
http://developer.android.com/design/get-started/principles.html

Real objects are more fun than buttons and menus

Allow people to directly touch and manipulate objects in your app. It reduces the cognitive effort needed to perform a task while making it more emotionally satisfying.

Get to know me

Learn peoples' preferences over time. Rather than asking them to make the same choices over and over, place previous choices within easy reach.

Keep it brief

Use short phrases with simple words. 

Pictures are faster than words

Consider using pictures to explain ideas.

Never lose my stuff

Save what people took time to create and let them access it from anywhere. Remember settings, personal touches, and creations across phones, tablets, and computers. It makes upgrading the easiest thing in the world.

Sprinkle encouragement

Break complex tasks into smaller steps that can be easily accomplished. Give feedback on actions, even if it's just a subtle glow.

Supporting Multiple Screens
http://developer.android.com/guide/practices/screens_support.html

Themes
Holo Light
Holo Dark
Holo Light with dark action bar

Touch Feedback
http://developer.android.com/design/style/touch-feedback.html

Density
http://developer.android.com/about/dashboards/index.html
ldpi (low), mdpi (medium), hdpi (high), and xhdpi (extra high)

Touchable UI components are generally laid out along 48dp units (=9mm)
This is comfortably in the range of recommended target sizes (7-10 mm) for touchscreen objects and users will be able to reliably and accurately target them with their fingers.

Spacing between each UI element is 8dp.

Design for Android
http://mobile.smashingmagazine.com/2012/07/26/android-design-tips/

http://coding.smashingmagazine.com/2011/06/30/designing-for-android/


Glossary
DPI (Dots Per Inch): Screen Density
DP (Density-independent Pixels)