In my app I have a predefined set of @Preview annotations:

@Preview(
    name = "Normal",
    group = "Screen",
    showBackground = true
)
@Preview(
    name = "Dark",
    group = "Screen",
    showBackground = true,
    uiMode = Configuration.UI_MODE_NIGHT_YES
)
@Preview(
    name = "RTL",
    group = "Screen",
    showBackground = true,
    locale = "iw"
)
@Composable
fun JustAComposable() {
   ...
}

The problem is that I have to duplicate this set across all of my composable functions.

I'd like to offer a solution. If accepted, it'll need to be implemented in androidx.compose.ui:ui-tooling-preview library and be enforced by Android Studio preview mechanism.

The Solution:

I'd like to be able to create my own preview annotation and annotate my annotation with that predefined previews.

Android Studio will have to dig up the internal preview annotations to identify those.

For example, my composable will look like this:

@MyPreview
@Composable
fun JustAComposable() {
    ...
}

And @MyPreview annotation will look like this:

@Preview(
    name = "Normal",
    group = "Screen",
    showBackground = true
)
@Preview(
    name = "Dark",
    group = "Screen",
    showBackground = true,
    uiMode = Configuration.UI_MODE_NIGHT_YES
)
@Preview(
    name = "RTL",
    group = "Screen",
    showBackground = true,
    locale = "iw"
)
@Retention(AnnotationRetention.SOURCE)
@Target(
    AnnotationTarget.FUNCTION
)
annotation class MyPreview

I think 2 things needs to be done:

• @Preview annotation will need to be targeted to functions and annotations (currently it only targets functions).
• Android Studio will have to recognize it and use the internal @Preview annotations