Target multiple screen sizes with your app

• Detailed info from google : https://developer.android.com/guide/practices/screens_support.html

• Screen size : actual physical size, measured as the screen's diagonal.

• Screen Size Categories :

  • small
  • normal
  • large
  • xlarge

• Screen density - dots per inch (dpi) :quantity of pixels within a physical area of the screen

• Screen Density Categories :

  • low
  • medium
  • high
  • extra-high
  • extra-extra-high
  • extra-extra-extra-high.

• Screen density info is usually found on each android device user manual of some kind of documentation.

• A set of six generalized densities:

  • ldpi (low) ~120dpi
  • mdpi (medium) ~160dpi
  • hdpi (high) ~240dpi
  • xhdpi (extra-high) ~320dpi
  • xxhdpi (extra-extra-high) ~480dpi
  • xxxhdpi (extra-extra-extra-high) ~640dp

• Orientation : portrait or landscape

• Resolution : Total number of pixels on a screen

• Density Independent Pixel ( dip):A virtual pixel unit that you should use when defining UI layout,to express layout dimensions or position in a density-independent way.WARNING : dip is DIFFERENT from dpi.Careful here :-)

• Some screen dimensions in dips:

  • xlarge screens are at least 960dp x 720dp
  • large screens are at least 640dp x 480dp
  • normal screens are at least 470dp x 320dp
  • small screens are at least 426dp x 320dp

• Transform from px to dip : dp = px * (dpi / 160)

• For android 3.2 and up ( Specifiers like small, normal, large and xlarge are deprecated.

• Use :

  • [smallestWidth] sw--dp (Examples:sw600dp,sw720dp)
  • [Available screen width ] w--dp (Examples: w720dp ,w1024dp)
  • [Available screen height] h--dp (Examples: h720dp h1024dp) to target a specific screen size.

• This example uses a combination of the following layout files and aliases to make our app work on regular phones ,7 inch tablets and 10 inch tablets :

  • res/layout/main.xml
  • res/layout-land/main.xml
  • res/layout/main_tablet.xml
  • res/values-large-land/layout.xml
  • res/values-sw600dp-land/layout.xml
  • res/values-xlarge/layout.xml
  • res/values-sw720dp/layout.xml

• Relevant files :

  • https://github.com/blikoon/Ubufundi/blob/master/App1.6/app/src/main/java/com/blikoon/app16/MainActivity.java
  • https://github.com/blikoon/Ubufundi/blob/master/App1.6/app/src/main/res/layout/activity_main.xml
  • https://github.com/blikoon/Ubufundi/blob/master/App1.6/app/src/main/res/layout/main.xml
  • https://github.com/blikoon/Ubufundi/blob/master/App1.6/app/src/main/res/layout/main_tablet.xml
  • https://github.com/blikoon/Ubufundi/blob/master/App1.6/app/src/main/res/values-large-land/layout.xml
  • https://github.com/blikoon/Ubufundi/blob/master/App1.6/app/src/main/res/values-sw600dp-land/layout.xml
  • https://github.com/blikoon/Ubufundi/blob/master/App1.6/app/src/main/res/values-sw720dp/layout.xml
  • https://github.com/blikoon/Ubufundi/blob/master/App1.6/app/src/main/res/values-w820dp/dimens.xml
  • https://github.com/blikoon/Ubufundi/blob/master/App1.6/app/src/main/res/values-xlarge/layout.xml