Sorting data from json in Kotlin

Question

I have data from json file which I display in recyclerview in my app. I'm trying to sort this data by year. That's how my code looks:

In MainActivity.kt everythings happend in fetchJson() function

private fun fetchJson(jsonUrl: String) {
    Log.d(TAG, "Attempting to fetch json")

    val request = okhttp3.Request.Builder().url(jsonUrl).build()

    val client = OkHttpClient()
    client.newCall(request).enqueue(object: Callback {
        override fun onFailure(call: Call, e: IOException) {
            Log.d(TAG, "Failed to execute request")
        }

        override fun onResponse(call: Call, response: Response) {
            val body = response.body()?.string()
            Log.d(TAG, "$body")

            val gson = GsonBuilder().create()

            val homeFeed = gson.fromJson(body, HomeFeed::class.java)
            homeFeed.standups.sortedWith(compareBy({it.year}))

            runOnUiThread {
                rv.adapter = Adapter(homeFeed)
            }
        }
    })
}

    fun <T> compareBy(vararg selectors: (T) -> Comparable<*>?): Comparator<T> {
        return Comparator<T> { a, b -> compareValuesBy(a, b, *selectors) }
    }

class HomeFeed is here:

class HomeFeed(val standups: List<StandUps>)

and data class StandUps:

data class StandUps(
        val artist: String,
        val title: String,
        val year: String,
        val poster: String,
        val description: String,
        val netflix_link: String,
        val imdb_rate: String,
        val imdb_link: String,
        val duration_min: String
)

It doesn't shows any errors or warnings, it just doesn't do anything. How could I achieve this?

Prithvi Bhola · Accepted Answer · 2018-08-29 10:10:33Z

2

You have to first store the sorted list in another variable and then use that variable to pass it to your adapter

val homeFeed = gson.fromJson(body, HomeFeed::class.java)
            val sortedHomeFeed = homeFeed.standups.sortedWith(compareBy({it.year}))

            runOnUiThread {
                rv.adapter = Adapter(sortedHomeFeed)
            }

The reason for this is, changes are not made to the original list following the concepts of immutability.

answered Aug 29, 2018 at 10:10

Prithvi Bhola

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2 Comments

Emil Majer Over a year ago

Thanks! Works perfect :)

Prithvi Bhola Over a year ago

Great! Cheers :D

TheTechWolf · Accepted Answer · 2018-08-29 10:09:05Z

1

If you want to sort your list ascending by a year you can do this:

val sortedStandUps = homeFeed.standups.sortedBy { it.year }

If you want to sort list descending do this:

val sortedStandUps = homeFeed.standups.sortedByDescending { it.year }

answered Aug 29, 2018 at 10:09

TheTechWolf

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Comments

IamVariable · Accepted Answer · 2018-08-29 10:03:14Z

0

Kotlin gives you easy sorting. Jus like below

make a temp object (i.e)., tempFilterData here

val standUps = tempFilterData?.sortedWith(compareBy({ it.Year }))

Now you can get the sorted data based on YEAR

answered Aug 29, 2018 at 10:03

IamVariable

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