I wanted to create a selfcontained “show version” component, simplest case would be like this

@Composable
    fun versionText(){
        val versionName = packageManager.getPackageInfo(packageName, 0).versionName
        Text(text = versionName)
    }

either this is the completely wrong way to do something like this, or I need some way to know if this composable is currently running in a preview, since the preview engine will not really show anything here (I think it even crashes silently somewhere)

The preview probably doesn’t work because it knows nothing about android context, since it’s not running on a device Try extracting access to packageManager outside of the component, passing only the string (in the snippet case) as an argument Otherwise there’s nothing wrong with this code

in the old view system, we could look for

isInEditMode()

to create a ‘preview’ version of the output. Would be nice to have something similar for code executed under @preview

Here comes the beauty of compose – you can easily compose This should come at basically no cost; might be wrong tho, but all the compose material components do this, so it should be quite cheap If you do something like this:

@Preview
@Composable
fun VersionTextPreview() {
  VersionTextImpl("1.2.3")
}

@Composable
fun VersionText() {
  val context = ContextAmbient.current.applicationContext
  val packageName = context.packageName
  val versionName = context.packageManager.getPackageInfo(packageName, 0).versionName

  VersionTextImpl(versionName = versionName)
}

@Composable
private fun VersionTextImpl(
  versionName: String
) {
  Text(versionName)
}

That way you both get your preview working, and your public API stays the same

feels like it could easy be bloated when/if you have many components that does this. a simple flag in the composable context sound for me easier, but I guess that is missing and i thank you for the example.