How do people handle full screen `@Preview`s? I ha...

# compose

[Marcin Wisniowski]

How do people handle full screen `@Preview`s? I have seen opinions previews should only be used for individual composables, not screens, but I also think the XML layout previews were useful and I would like a preview of an entire screen.

[Marcin Wisniowski]

I have a screen that contains a composable that cannot run in a preview. In the View world I would use isInEditMode() in it to correctly handle that, but with Compose it just prevents my entire screen from being previewable?

[allan.conda]

Why can’t it run in preview?

[allan.conda]

You can try LocalInspectionMode.current which is similar to that Edit Mode

[Marcin Wisniowski]

Why can’t it run in preview?

It's a map view (think Google Maps), there would need to be a lot of mocking just for it to display nothing in the end. I'd rather just not display it.

[Marcin Wisniowski]

You can try LocalInspectionMode.current  which is similar to that Edit Mode

I haven't seen that, thanks!

[allan.conda]

Preview is nice, but don’t you want to test your Screen as well?

How about refactoring that map subcomponent into a Slot, you can test the rest.

[Chris Sinco [G]]

I’m not sure if MapView is supported in Compose preview - @nosuid can comment

[Chris Sinco [G]]

But as far as previewing a “screen”, it’s really a Composable with a device set in the Preview parameters, e.g. Pixel3

[Chris Sinco [G]]

You can also change height and width of the Preview with individual parameters

[Marcin Wisniowski]

The map Composable I am using is from a third party library, not from Google.

[Chris Sinco [G]]

What errors are you getting from the Preview?

[Marcin Wisniowski]

No errors, my question was just about the problem of having a Composable that has complex dependencies, that would require a lot of code in the @Preview function to stub in a way where it wouldn't crash. LocalInspectionMode.current solves this because I can disable the Composable to prevent it from crashing. In this case the Composable takes a function that produces an InputStream for a map tile that it then draws. Unless I can produce `InputStream`s in the @Preview function that can be read as valid PNG's the Composable won't work.