How to sort Data class object in Array with LocalDate.now() in Kotlin-CodePudding

I get this ArrayList named items containing several Data class in Adapter.

[DiaryCard(writeTime=2023-01-04, name=신혜정, stepCount=0, mood=2131230894, diary=안녕하세요), 
    DiaryCard(writeTime=2023-01-04, name=신혜정, stepCount=11, mood=2131230894, diary=hi), 
    DiaryCard(writeTime=2023-01-04, name=신태건, stepCount=0, mood=2131230898, diary=대단히 반갑습니다)]

I want to sort them by key 'writeTime' before I bind this data to View in ViewHolder.

   var items = items
    var sortItems = items.sortedBy { it.writeTime }

    inner class CardViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {

        var userWriteTime: TextView = itemView.findViewById(R.id.userWriteTime)
        var userNameView: TextView = itemView.findViewById<TextView>(R.id.userName)
        var userStepCountView: TextView = itemView.findViewById<TextView>(R.id.userStepCount)
        var userMoodView: ImageView = itemView.findViewById<ImageView>(R.id.userMood)
        var userDiaryView: TextView = itemView.findViewById<TextView>(R.id.userDiary)

        fun bind(position: Int) {
            Log.d("결과아", "items: $items")
            Log.d("결과아", "sortItems: $sortItems")

            userWriteTime.text = sortItems[position].writeTime
            userNameView.text = sortItems[position].name
            userStepCountView.text = "${sortItems[position].stepCount}보"
            userMoodView.setImageResource((sortItems[position].mood ?: 2131230873).toInt())
            userDiaryView.text = sortItems[position].diary

        }
    }

So I create var sortItems which sort items by using sortedBy.

And I link this sortItems var to function bind instead of items.

But it won't work.

When I print items and sortItems, items show above ArrayList containing 3 DiaryCard Data class.

But sortItems show empty ListArray, [].

So How can I sort ArrayList by one component of DataClass?

Plus, my writeTime is String value coming from LocalDate.now().

How can I sort them LocalDate.now() in order for the most recent data to come first?

I use Kotlin, please help me with detail code.

Thank you!

CodePudding user response：

items.sortByDescending { item -> item.writeTime }

The method sortByDescending mutates the original list sorting it descending using the size of the list as selector to make the comparison between elements.

CodePudding user response：

You can use sortByDescending to get recents one first. Documentation

var sortItems = items.sortByDescending { it.writeTime }