Is there a way to use Parceler with Kotlin data classes and constructor for serialization without using @ParcelProperty
annotation for each field?
If I try and use library like this:
@Parcel data class Valve @ParcelConstructor constructor(val size: Int)
I get Error:Parceler: No corresponding property found for constructor parameter arg0
. But if I add @ParcelProperty("size")
it works just fine.
Why is that?
Update:
There are other another way to use this library.
I could just remove @ParcelConstructor
annotation, but then I will get errorError:Parceler: No @ParcelConstructor annotated constructor and no default empty bean constructor found.
I think (haven't tested it) I also could make all constructor parameters optional and add @JvmOverloads
but that has a side effect that I have to check all properties of the class if they are null or not.
Update 2:
This is what worked for me:
@Parcel data class Valve(val size: Int? = null)
In short generated Java class must have default empty constructor. One way to achieve that is to do as above - all variables should have default values.
Data classes in Kotlin are immutable and it's easy enough to create a constructor for a data class with multiple fields. Note that it's compulsory to have a primary constructor in a data class.
The kotlin-parcelize plugin provides a Parcelable implementation generator. @Parcelize requires all serialized properties to be declared in the primary constructor. The plugin issues a warning on each property with a backing field declared in the class body.
All you need to do is add @Parcelize annotation to the data class to make it Parcelable. That's all. You can send your data object from source activity like this… and receive the data in your destination activity through the Intent like this…
Parcelable is an Android interface that allows you to serialize a custom type by manually writing/reading its data to/from a byte array. This is usually preferred over using reflection-based serialization as it is faster to build in your serialization at compile time versus reflecting at runtime.
According to the docs, Parceler by default works with public fields. But a usual Kotlin data class
(as in your example) is rather a "traditional getter/setter bean", since every Kotlin property is represented by a private field and a getter/[setter].
TL; DR: I think this will work:
@Parcel(Serialization.BEAN) data class Valve(val size: Int = 10)
Note the default value, it allows Kotlin to automatically generate an additional empty constructor, which is required by the Java Been specification.
Another way would be to mark the constructor that we already have:
@Parcel(Serialization.BEAN) data class Driver @ParcelConstructor constructor(val name: String)
The specific document: https://github.com/johncarl81/parceler#gettersetter-serialization
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