Develop Reference

MutableList<Any> addAll kotlin entire arraylist added as object

Following is my code
var items : MutableList<Any> = arrayListOf()
items.add(TeacherDetails(it?.photo,it?.firstName,it?.lastName,it?.level))
items.add(TeacherBio(it?.bio))
items.add(TitleAccreditations(getString(R.string.acreditations)))
items.add(SessionsTitle(it?.firstName + getString(R.string.apostrophe) + getString(
R.string.sessions)))
items.addAll(listOf(it?.classes ?: arrayListOf()))
items.add(IntroVideo(it?.introVideo))
items.addAll(it?.teachingAccreditations?.split("\n")?.map { Accreditation(
it
) }?: emptyList())
Issue is at following line it is adding entire list as object instead of individual item.
items.addAll(listOf(it?.classes ?: arrayListOf()))
Following is my model
data class Teacher(
#field:SerializedName("firstName")
val firstName: String? = null,
#field:SerializedName("lastName")
val lastName: String? = null,
#field:SerializedName("teacherId")
val teacherId: String? = null,
#field:SerializedName("introVideo")
val introVideo: String? = null,
#field:SerializedName("level")
val level: String? = null,
#field:SerializedName("teachingAccreditations")
val teachingAccreditations: String? = null,
#field:SerializedName("classes")
val classes: List<ClassesItem?>? = null,
#field:SerializedName("photo")
val photo: String? = null,
#field:SerializedName("bio")
val bio: String? = null
)

I guess because your type of list is Any, it will consider adding list instance also as an object, so instead it as listOf() just add directly
items.addAll(it?.classes?.filterNotNull()?: arrayListOf())

Create an AdapterFactory for gson for dynamic Types

I have a JSON string that I need to converted to data class object in Kotlin, the problem is that there is a field (details) that can have a different structure depending of the value of another field like this
val jsonString1 = "{'name': 'Juan', 'phase': 'step1', 'details': { 'name': 'product 1' }}"
val jsonString2 = "{'name': 'Juan', 'phase': 'step2', 'details': { 'position': 10 }}"
now I have something like
data class Customer(
var name: String? = null
var phase: String? = null
var details: Details? = null
)
data class Details(
var name: String? = null
)
data class Details2(
var position: Int? = null
)
now with gson I know I can
Gson().fromJson(jsonString1, Customer::class.java)
I want to be able to automatically use the right data class depending on the value of the phase field, I know I can create an adapterFactory, but I can't figure out how, an in kotlin is worse
I was reading this post
http://anakinfoxe.com/blog/2016/02/01/gson-typeadapter-and-typeadapterfactory/
and I'm pretty sure is the way to go, but I can't quite get it

Yep, it's pretty easy to write such adapter. I've slightly changed your example:
data class Customer(
var name: String? = null,
var phase: String? = null,
var details: Details? = null
)
sealed class Details {
data class Details1(var name: String? = null) : Details()
data class Details2(var position: Int? = null) : Details()
}
class CustomerDeserializer : JsonDeserializer<Customer> {
override fun deserialize(json: JsonElement, typeOfT: Type?, context: JsonDeserializationContext?): Customer {
val customerObject = json.asJsonObject
val detailsObject = customerObject.getAsJsonObject("details")
val details = if (detailsObject.has("name")) {
Details.Details1(detailsObject.get("name").asString)
} else {
Details.Details2(detailsObject.get("position").asInt)
}
return Customer(
name = customerObject.get("name").asString,
phase = customerObject.get("phase").asString,
details = details
)
}
}
fun main() {
val gson = GsonBuilder()
.registerTypeAdapter(Customer::class.java, CustomerDeserializer())
.create()
println(gson.fromJson(jsonString1, Customer::class.java))
println(gson.fromJson(jsonString2, Customer::class.java))
}

data class Customer(
var name: String? = null
var phase: String? = null
var details: Details? = null
)
data class Details(
var name: String? = null
var position: Int? = null
)
Define Details class in this way
Gson().fromJson(jsonString1, Customer::class.java)
return a Customer either name is null or position is null

Android Kotlin save data class in Firebase Database

I am working on an Android application in Kotlin which integrate Firebase.
Now I want to store my data (Kotlin data class) into Firebase Database.
Data Classes:
#Parcelize
data class Trip(
val fromAddress: String,
val toAddress: String,
val fromLocation: String,
val toLocation: String,
val orderUid: String
) : Parcelable
#Parcelize
data class Order(val trip: Trip, val date: Date, var status: OrderStatus, val userUid: String) : Parcelable {
var pickUpDate: Date? = null
var dropOffDate: Date? = null
var price: Double? = null
}
Fireabase Database write operation:
fun createNewOrder(
fromAddress: String,
toAddress: String,
fromLocation: Location,
toLocation: Location
) {
val fromGeoLocation = fromLocation.convertToGeoLocation()
val toGeoLocation = toLocation.convertToGeoLocation()
val userUid = sharedPreferences[CURRENT_USER_UID_KEY, ""]!!
val orderKey = databaseReference.child(DB_ORDERS_KEY).push().key
val tripKey = databaseReference.child(DB_TRIPS_KEY).push().key
val trip = orderKey?.let { createNewTrip(fromAddress, toAddress, it) }
val order = trip?.let { Order(it, Date(), OrderStatus.PENDING, userUid) }
if (trip != null && order != null && !userUid.isNullOrEmpty()) {
ordersGeoFire.setLocation(trip.fromGeoLocation, fromGeoLocation)
ordersGeoFire.setLocation(trip.toGeoLocation, toGeoLocation)
val allData = mutableMapOf<String, Any>()
allData["/$DB_TRIPS_KEY/$tripKey"] = trip?.convertToMap()
allData["/$DB_ORDERS_KEY/$orderKey"] = order?.convertToMap()
allData["/$DB_USERS_KEY/$userUid/$DB_ORDERS_KEY/$orderKey"] = true
databaseReference.updateChildren(allData)
}
}
I received this error:
com.google.firebase.database.DatabaseException: No properties to serialize found on class kotlin.Unit
Any suggestions?

The problem in your code is that the fileds inside your Trip class are not initialized. A recommended way in which you can create your model class would be:
class Trip(
val displayName: String = "",
val email: String = "",
val photoUrl: String = "",
val userId: String = ""
)
This is only what you need. And a way to create a new object of your Trip class, would be:
val trip = Trip(displayName, email, photoUrl, userId)

It was my mistake, because I was forget to add return type in my extensions convertToMap functions. Now they look like this:
fun Trip.convertToMap(): MutableMap<String, Any> {
val map = mutableMapOf<String, Any>()
map["fromAddress"] = fromAddress
map["toAddress"] = toAddress
map["fromGeoLocation"] = fromGeoLocation
map["toGeoLocation"] = toGeoLocation
map["orderUid"] = orderUid
return map
}
And also thanks to #Alex Mamo for his answer, it helps me in my investigation.
Now my code looks like this and works fine:
#Parcelize
data class Trip(
var fromAddress: String = "",
var toAddress: String = "",
var fromGeoLocation: String = "",
var toGeoLocation: String = "",
var orderUid: String = ""
) : Parcelable
#Parcelize
data class Order(
var trip: Trip? = null,
var date: Date? = null,
var status: OrderStatus? = null,
var userUid: String = ""
) : Parcelable {
var pickUpDate: Date? = null
var dropOffDate: Date? = null
var price: Double? = null
}
fun createNewOrder(
fromAddress: String,
toAddress: String,
fromLocation: Location,
toLocation: Location
): LiveData<Order> {
orderLiveData = MutableLiveData()
orderLiveData.value = null
val userUid = sharedPreferences[CURRENT_USER_UID_KEY, ""]!!
val orderKey = databaseReference.child(DB_ORDERS_KEY).push().key
val tripKey = databaseReference.child(DB_TRIPS_KEY).push().key
val trip = orderKey?.let { createNewTrip(fromAddress, toAddress, fromLocation, toLocation, it) }
val order = trip?.let { Order(it, Date(), OrderStatus.PENDING, userUid) }
if (trip != null && order != null && !userUid.isNullOrEmpty()) {
val allData = mutableMapOf<String, Any>()
allData["/$DB_TRIPS_KEY/$tripKey"] = trip.convertToMap()
allData["/$DB_ORDERS_KEY/$orderKey"] = order.convertToMap()
allData["/$DB_USERS_KEY/$userUid/$DB_ORDERS_KEY/$orderKey"] = true
databaseReference.updateChildren(allData) { databaseError, databaseReference ->
if (databaseError == null) orderLiveData.value = order
}
}
return orderLiveData
}
Hope this will be helpful

Parameter specified as non-null is null exception, using gson on web api return null

How to prevent gson from recieving null object from web api
when Web api return null
{ "events": null }
it will become this exception
java.lang.IllegalArgumentException: Parameter specified as non-null is null: method kotlin.jvm.internal.Intrinsics.checkParameterIsNotNull, parameter data
Gson usage
val data = gson.fromJson(apiRepository
.doRequest(TheSportDBApi.getLatestMatch(league)),
MatchResponse::class.java)
My data class
data class MatchResponse (val events: List<Match>)
Match.class
data class Match(
#SerializedName("idEvent")
var eventId: String? = null,
#SerializedName("strDate")
var matchDate: String? = null,
//home
#SerializedName("strHomeTeam")
var homeTeam: String? = null,
#SerializedName("intHomeScore")
var homeScore: String? = null,
var homeBadger:String?=null,
//away
#SerializedName("strAwayTeam")
var awayTeam: String? = null,
#SerializedName("intAwayScore")
var awayScore: String? = null,
var awayBadge: String? = null
)

Is your event variable of the MatchResponse class nullable? Something like:
val event: Event?

You can make that particular object nullable using ? in kotlin
data class Article(
val title: String,
val body: String,
val events: Events? = null, //Make it nullable
val payWall: Boolean = false,
val titleImage: String? = null
)

moshi kotlin non constructor properties not serialized

I have a class defined like this:
data class Medicalnfo(
#Json(name = "allergies") val allergies: List<Allergy>? = null
): ProfileModel(){
#Json(name = "has_allergies") val hasAllergies: Boolean = allergies != null && allergies.isNotEmpty()
}
The problem is that hasAllergies is not included in the json serialization generated by Moshi. How can this be achieved?
Here is the test
#Test
fun medicalInfoJsonContainsFlags(){
val adapter = moshi.adapter(Medicalnfo::class.java)
val jsonStr = adapter.toJson(Medicalnfo(allergies = listOf())) //value is {"allergies":[]}
assert(jsonStr.contains("has_allergies"))
}

If you make hasAllergies as var it will work
data class Medicalnfo(
#Json(name = "allergies") val allergies: List<Allergy>? = null
): ProfileModel(){
#Json(name = "has_allergies") var hasAllergies: Boolean = allergies != null && allergies.isNotEmpty()
}