How to get the build/version number of your Android application?

Question

I need to figure out how to get or make a build number for my Android application. I need the build number to display in the UI.

Do I have to do something with

Answer 1

As in 2020 : API 28 "versionCode" is deprecated so we can use "longVersionCode"

Sample code in kotlin

  val manager = context?.packageManager
        val info = manager?.getPackageInfo(
            context?.packageName, 0
        )

        val versionName = info?.versionName
        val versionNumber = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) {
            info?.longVersionCode
        } else {
            info?.versionCode
        }