How to create an extension for compose functions without using @Composable annotation?-CodePudding

Problem Description

I'm creating an abstraction for my compose functions that use my custom view:

@Composable
fun DisposeBanner(bannerView: BannerView) {
    DisposableEffect(key1 = true) {
        onDispose {
            bannerView.destroyAd()
        }
    }
}

However, as this function doesn't actually render any components I didn't want it to stick with the @Composable markup, but rather to indicate that it can only be used in compose functions through an extension.

My failed attempt

When trying to do:

fun Composable.disposeBanner(bannerView: BannerView) {
    DisposableEffect(key1 = true) {
        onDispose {
            bannerView.destroyAd()
        }
    }
}

I get an error saying: "@Composable invocations can only happen from the context of a @Composable function"

Is it possible to do what I want?

CodePudding user response：

Composable is a function. You cannot do extensions on functions. And the error clearly states that you are trying to use composable DisposableEffect function (which is a normal composable function that do not render any ui) in non-composable function.

You are overthinking this. There are a lot of composables that do not render any UI. @Composable annotation is NOT bound to UI in any way. So doing a composable function that do not render anything is totally and completely fine