Does epect & actual work with interfaces? I w...

# multiplatform

[Stefan Oltmann]

Does epect & actual work with interfaces?

I want to define a Interface like so:

expect interface Image

expect interface ImageLoader {

    fun loadFullImage(photo: Photo): Image

    fun loadThumbnailImage(photo: Photo): Image

}

And for Android it should load a "ImageBitmap"

actual interface Image // ???

actual interface ImageLoader {

    actual fun loadFullImage(photo: Photo): ImageBitmap

    actual fun loadThumbnailImage(photo: Photo): ImageBitmap

}

And for iOS "Image" should be "UIImage" of course.

Is that possible?

[Osman Saral]

I'm not sure but you can use something like this.

expect class Image

//for Android
actual typealias Image = Bitmap

//for iOS
actual typealias Image = UIImage

after that, you can use common Interface functions to return that typealias

[Stefan Oltmann]

I will try that. Thank you! 🙂

[Stefan Oltmann]

Ok, "actual typealias" is indeed the mechanic I'm looking for. So thank you for pointing me to that.

If I try to define "actual typealias MyImage = NSImage" for my macOS target it gives an error. "actual typealias MyImage = UIImage" seems to be fine.

Conflicting overloads: public final actual fun <init>(data: NSData): MyImage /* = NSImage / defined in com.sampleapp.shared.MyImage, public final actual fun <init>(contentsOfFile: String): MyImage / = NSImage / defined in com.sampleapp.shared.MyImage, public final actual fun <init>(contentsOfURL: NSURL): MyImage / = NSImage / defined in com.sampleapp.shared.MyImage, public final actual fun <init>(byReferencingFile: String): MyImage / = NSImage / defined in com.sampleapp.shared.MyImage, public final actual fun <init>(byReferencingURL: NSURL): MyImage / = NSImage / defined in com.sampleapp.shared.MyImage, public final actual fun <init>(dataIgnoringOrientation: NSData): MyImage / = NSImage */ defined in com.sampleapp.shared.MyImage

[Stefan Oltmann]

Should I file a ticket or do I just use this wrong?