Screen-size Buckets
Android has included support for three screen-size “buckets” since 1.6, based on these “dp” units: “normal” is currently the
most popular device format (originally 320x480, more recently higher-density 480x800); “small” is for smaller screens, and
“large” is for “substantially larger” screens. Devices that fall in the “large” bucket include the Dell Streak and original 7”
Samsung Galaxy Tab. Android 2.3 introduced a new bucket size “xlarge”, in preparation for the approximately-10” tablets
(such as the Motorola Xoom) that Android 3.0 was designed to support.
The definitions are:
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. (Android does not currently support screens smaller than this.)
Here are some more examples of how this works with real screens:
A QVGA screen is 320x240 ldpi. Converting to mdpi (a 4/3 scaling factor) gives us 426dp x 320dp; this matches
the minimum size above for the small screen bucket.
The Xoom is a typical 10” tablet with a 1280x800 mdpi screen. This places it into the xlarge screen bucket.
The Dell Streak is a 800x480 mdpi screen. This places it into the bottom of the large size bucket.
Understanding Screen Densities and the “dp”
Android has included support for three screen-size “buckets” since 1.6, based on these “dp” units: “normal” is currently the
most popular device format (originally 320x480, more recently higher-density 480x800); “small” is for smaller screens, and
“large” is for “substantially larger” screens. Devices that fall in the “large” bucket include the Dell Streak and original 7”
Samsung Galaxy Tab. Android 2.3 introduced a new bucket size “xlarge”, in preparation for the approximately-10” tablets
(such as the Motorola Xoom) that Android 3.0 was designed to support.
The definitions are:
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. (Android does not currently support screens smaller than this.)
Here are some more examples of how this works with real screens:
A QVGA screen is 320x240 ldpi. Converting to mdpi (a 4/3 scaling factor) gives us 426dp x 320dp; this matches
the minimum size above for the small screen bucket.
The Xoom is a typical 10” tablet with a 1280x800 mdpi screen. This places it into the xlarge screen bucket.
The Dell Streak is a 800x480 mdpi screen. This places it into the bottom of the large size bucket.
Understanding Screen Densities and the “dp”
