Android Support package knowledge, androidsupport
The Android Support Library package is a set of code libraries that provide compatibility with later versions of framework APIs. These code libraries achieve the same effect as APIs that can only be used in a specified version. each Support Library is a compatible Library of a specified version, and the suffix vX of each Support package represents the meaning. Android has a version number for each version. For example, 2.1 is 7, 4.0 is 14, and 5.0 is 21. Here, the number after v represents the lowest version level that he can use. The reason why he cannot be used in a lower version is that with the upgrade of the version, there are many features or APIs that are not supported in the new version. Therefore, if you use these support packages in the old version, the application may crash.
Each supported database contains sample code to help us learn how to use these Apis. The code is included in the files downloaded by the SDK manager and included in the SDK installation directory. The list is as follows:
L 4 v code example: <sdk>/extras/android/support/samples/Support4Demos/
L 7v code example: <sdk>/extras/android/support/samples/Support7Demos/
L 13v code example: <sdk>/extras/android/support/samples/Support13Demos/
L App Navigation: <sdk>/extras/android/support/samples/SupportAppNavigation/
For more information, see: http://www.cnblogs.com/l2rf/p/4980277.html