CODEWITHSUNDEEP
androidkotlin
Julia
Julia

Reputation: 369

How to convert Unit to String in kotlin (UPD doesn't work after adding synchronous code)

I have function which doesn't return any:

   fun getName(name:String){

        val requestUrl =
            "https://api/app/getherp"
        val resRequest =object :JsonObjectRequest(
            Request.Method.GET, requestUrl,null,
            { response ->

            },
            { error ->
              
            }
        )
        queue.add(resRequest)
    }

I want return value getName's function like this:

fun getNorm(name: String): String {
        return getName(name)
    }

but I get error:

Type mismatch.
Required:
String
Found:
Unit

I know that if I add .toString to return getName(name) - this is not enough. Because in this case I get as result kotlin.Unit . What have I to do?? Thank you

UPD: as advice here I added synchronous code. But result is the same. My code is now:

fun getName(
       name: String,
        requestResult: (res: JSONObject) -> Unit,
        requestError: ((err: String) -> Unit)? = null
    ) {

val requestUrl = "https://api/app/getherp"

        val jsonObjectRequest = object : JsonObjectRequest(Request.Method.GET, requestUrl, null,
            { response ->
               requestResult(response)

            },
            { error ->
              
                requestError?.invoke(error.toString());
            }
        ) {
            override fun getHeaders(): MutableMap<String, String> {
                return getAuthHeaders()
            }
        }
        queue.add(jsonObjectRequest)
    }

and I call this function like this:

fun getNamePers(
    name: String, result: (res: JSONObject) -> Unit,
    error: ((err: String) -> Unit)? = null
) {
   MyClass.getName(name, result, error)
}

Upvotes: 2

Views: 2028

Answers (2)

Martin Zeitler
Martin Zeitler

Reputation: 76579

fun getName(name:String) would need to return String in a synchronous manner. As this doesn't seem to be possible with JsonObjectRequest, I'd question the whole approach. fun getNorm(name: String): String also appears quite superfluous, as it only wraps the other one method.

You'd need to move your code into { response -> ... } - or call a method from there.

See Asynchronous Programming Techniques for a more detailed explanation.

When setting a few break-points, the order of execution merely explains itself.

Upvotes: 2

Ashish Sharma
Ashish Sharma

Reputation: 576

Function getNorm should return String but it returns getName and expects getName function to return a String, but getName function doesn't return anything which is why it is giving unit error, either remove the return type String, or return the string which you need from getName

Upvotes: 2

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