Hi everyone. I'm setting up a MultiPlatform project with two platforms (JVM and Android). And I hav...

# multiplatform

[Zeeshan Syed]

Hi everyone.
I'm setting up a MultiPlatform project with two platforms (JVM and Android).

And I have a common UI using Compose.

Let's say I also have a function which reads an NFC card connected to the JVM machine/Android.

For this, I created a actual/expect fun readCard()

Now the issue is, the function needs 3 strings of keys to read the card.
So, I made the code as
expect fun readCard(k1: String, k2: String, k3: String).

In addition to this, for Android, it needs a Tag object as well. Now, how do I pass it to the function.

I cannot add the Tag as 4th argument because in common:desktopMain, it doesn't know about what Tag is and it doesn't need.

Alternatively I can make it as Any. But do you also think that is the only option or is there any better way?

[Big Chungus]

Expect/actual tag too and require it for jvm actual too and just don't use it?

[Big Chungus]

Although it sounds like a job for interfaces and DI

[Zeeshan Syed]

That Tag class is a part of the Android SDK.
So, I cannot put that in arguments

[Big Chungus]

You can. actual typealias on android, shell class on jvm

[Big Chungus]

Although I'm not sure how you'd go about obtaining it on common. Maybe another expect provider fun?

[Zeeshan Syed]

Yeah. In common for expect function also I cannot add this Tag argument.

Even for the provider, we have to declare the return type as well right.

[Big Chungus]

Which would be your expect Tag

[Zeeshan Syed]

This code is in common module. Tag class not available here.

[Zeeshan Syed]

neither I can put as argument nor I can set as return type. That Tag class is available only in android module or in the common:androidMain

[Big Chungus]

https://kotlinlang.slack.com/archives/C3PQML5NU/p1677757785761129?thread_ts=1677756689.105479&cid=C3PQML5NU

[Big Chungus]

// commonMain
expect class Tag

// androidMain
actual typealias Tag = android.nfc.Tag

// jvmMain
actual class Tag

[Zeeshan Syed]

Ohh.. that's neat. I failed to understand it without an example 😅.

Thank you.

[Friedger]

@Zeeshan Syed Is there a library for NFC?`Something like https://github.com/revtel/react-native-nfc-manager for react native?