android - Pass Parcelable argument with compose navigation

Question

I want to pass a parcelable object (BluetoothDevice) to a composable using compose navigation.

Passing primitive types is easy:

composable(
  "profile/{userId}",
  arguments = listOf(navArgument("userId") { type = NavType.StringType })
) {...}

navController.navigate("profile/user1234")

But I can't pass a parcelable object in the route unless I can serialize it to a string.

composable(
  "deviceDetails/{device}",
  arguments = listOf(navArgument("device") { type = NavType.ParcelableType(BluetoothDevice::class.java) })
) {...}

val device: BluetoothDevice = ...
navController.navigate("deviceDetails/$device")

The code above obviously doesn't work because it just implicitly calls toString().

Is there a way to either serialize a Parcelable to a String so I can pass it in the route or pass the navigation argument as an object with a function other than navigate(route: String)?

Answer 1

Basically you can do the following:

// In the source screen...
navController.currentBackStackEntry
    ?.arguments?.putParcelable("bt_device", device)
navController.navigate("deviceDetails")

And in the details screen...

val device = navController.previousBackStackEntry
    ?.arguments?.getParcelable<BluetoothDevice>("bt_device")