Store Custom Kotlin Data Class to disk

Question

I'm having trouble figuring out a good way to do a Favorites list. I have a recycler view with a button to store an item to Favorites, I can easily just store this items id but then I have to remake network calls just to get some basic info to fill the list item view.

Here is a screen shot of my recycler view..

These items are a simple data class defined as follows

data class CoinListItem(
    @Expose
    @SerializedName("id")
    var id: String? = null,
    @Expose
    @SerializedName("name")
    var name: String? = null,
    @Expose
    @SerializedName("symbol")
    val symbol: String? = null,
    @Expose
    @SerializedName("website_slug")
    val slug: String? = null,
    @Expose
    @SerializedName("quote")
    val quoteItem: CoinListQuoteItem? = null,
    @Expose
    @SerializedName("tags")
    val tags: List<String>? = null): Parcelable

Is there a way to save custom objects to disk?

Answer 1

Yep. You can depict class as Serializable CoinListItem(...): Serializable thus you tell the system that it can be serialized to and deserialized from text. Next - you create File serialize your object by

    val item = CoinListItem()
    val file = FileOutputStream("file.txt") // here should be a full path and name
    val outStream = ObjectOutputStream(file)

    // Method for serialization of object
    outStream.writeObject(item)

    outStream.close()
    file.close()

To deserialize it use

    val file = FileInputStream("file.txt")
    val inStream = ObjectInputStream(file)

    // Method for deserialization of object
    val item = inStream.readObject() as CoinListItem

    inStream.close()
    file.close()

Hope it helps.