I'm using Gsson to convert JSON to Kotlin data class. While creating data class object I want to parse the value in init method. But init never called and generated object's values are null.
data class Configuration (val groupId:Int, val key:String, val source:String){
val query:String
val search:String
init {
val obj = JSONObject(key)
query = obj.getString("q")
search = obj.getString("search")
}
}
When I got the object of Configuration from Gson, query and search value is always null and init block was never executed. I also tried constructor and without data keyword, results are same.
init block is only executed when primary constructor is called. But gson doesn't call primary constructor when parsing json to object.
To solve this, I think, you should implement query and search as a get method or use lazy init. Something like this:
data class Configuration(val groupId: Int, val key: String, val source: String) {
var query: String = ""
get() {
if (field == null) {
initInternal()
}
return field
}
private set
var search: String? = null
get() {
if (field == null) {
initInternal()
}
return field
}
private set
private fun initInternal() {
val obj = JSONObject(key)
query = obj.getString("q")
search = obj.getString("search")
}
}
or any other approach which will suite best to your requirements.