CODEWITHSUNDEEP
androidkotlin
Hasan A Yousef
Hasan A Yousef

Reputation: 24908

If null else not working

I want to execute a msg if the location is null, and another msg if it is not null, so I'm trying use the elvis-operator as a?.let{} ?: run{} statement, but the run part is not reachable, and it tells me it is not required nor non-nullable!

The function I'm getting the error with, is:

getLocation(
           context,
                { location ->
                    location?.let {
                        msg = ("As of: ${Date(it.time)}, " +
                                "I am at: http://maps.google.com/?q=@" +
                                "${it.latitude}, ${it.longitude}, " +
                                "my speed is: ${it.speed}")
                    } ?: run { . // Getting error here
                        msg = "Sorry, it looks GPS is off, no location found\""
                    }

                    sendSMS(
                            context,
                            address,
                            msg,
                            subId
                    )
                }
        )

Th getLocation function is:

object UtilLocation {
    private lateinit var l : Location

    @SuppressLint("MissingPermission")
    fun getLocation(context: Context, callback: (Location) -> Unit) {
        fusedLocationClient = LocationServices.getFusedLocationProviderClient(context!!)

        fusedLocationClient.lastLocation
                .addOnSuccessListener { location : Location? ->
                    this.l = location!!
                    callback.invoke(this.l)
                }
    }
}

Upvotes: 1

Views: 165

Answers (1)

ice1000
ice1000

Reputation: 6569

In fun getLocation(context: Context, callback: (Location) -> Unit), the parameter Location of callback is NotNull, so it's never null, this is why location?.let causes a warning -- it's never null so it's impossible to enter the ?: run part of the expression.

AFAIK you want this code (parameter of callback is made Nullable, removed unnecessary NotNull assertion, add null check instead of assertion):

object UtilLocation {
    private lateinit var l : Location

    @SuppressLint("MissingPermission")
    fun getLocation(context: Context, callback: (Location?) -> Unit) {
        fusedLocationClient = LocationServices.getFusedLocationProviderClient(context)
        fusedLocationClient.lastLocation
                .addOnSuccessListener { location : Location? ->
                    if (location != null) this.l = location
                    callback.invoke(this.l)
                }
    }
}

And now this code work. I've did a little refactor to make it look nicer

getLocation(context) { location ->
    msg = location?.let {
        "As of: ${Date(it.time)}, " +
                "I am at: http://maps.google.com/?q=@" +
                "${it.latitude}, ${it.longitude}, " +
                "my speed is: ${it.speed}"
    } ?: run {
        "Sorry, it looks GPS is off, no location found\""
    }

    sendSMS(context, address, msg, subId)
}

Upvotes: 5

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