Android APIs are known by an API level, for example, API level 23.
An API level represents a specific Android release. If you open Android SDK Manager in Visual Studio, you will see the following screen:
Each API level is specific to an Android release. An Android release is known by multiple names:
- The API level, such as API level 23
- The Android version, such as Android 6.0
- A code name, such as Marshmallow
So, we can say that APIs have an integer value, a number to identify the release, because with each release this API level changes, and users upgrade their Android versions as they get released.
An Android app should be able to run on different APIs and should be compatible with previous versions of releases, so that old devices can run applications as well, and when a user updates their OS version to a new one, existing apps don't break on their phones...
