为什么此 Kotlin 扩展未能通过 Android Studio Lint 检查？

Question

Within Android development, there is often a time in which a block of code needs to be executed if and only if the device's SDK is greater than or equal to a minimum version.

To avoid the often ugly and repetitive nature of this code, I created the following extension.

inline fun <T> runWithMinSdk (minVersion: Int, func: () -> T) {
    if (android.os.Build.VERSION.SDK_INT >= minVersion) { func() }
}

Nothing too fancy, and seems to do the trick on paper.

However , when I use this code as such:

fun myFun {
    runWithMinSdk(Build.VERSION_CODES.O) {
        exampleMethodThatRequiresOreo()
    }
}

Android Studio throws a hissy fit and it fails the Lint checks, asking to either suppress 'NewApi' warnings within myFun() or wrapping the runWithMinSdk block with if android.os.Build.VERSION.SDK_INT ... etc

Is there a better way to achieve this functionality, make it pass the Lint checks or is none of this possible using extensions?

Answer 1

Based on this this discussion in the Kotlin forum it seems like doing something like this isn't possible, because Lint can only look at the current function for annotations. For instance if you do

val func = @TargetApi(26) { exampleMethodThatRequiresOreo() }
runWithMinSdk(Build.VERSION_CODES.0, func)

you won't get the warning, but that also kinda defeats the purpose of this extension function. The OP in the discussion above mentions taking the feature request to Anko, but I couldn't find an associated issue there.

Answer 2

The androidX annotation library provides a nice solution for this:

@ChecksSdkIntAtLeast(parameter = 0)
inline fun <T> runWithMinSdk(minVersion: Int, func: () -> T) {
    if (android.os.Build.VERSION.SDK_INT >= minVersion) { func() }
}