StickyTimeLine is timeline view for android

    repositories {
        maven { url 'https://jitpack.io' }
    }

    dependencies {
        compile 'com.github.sangcomz:StickyTimeLine:v0.0.17'
    }

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="xyz.sangcomz.stickytimeline.MainActivity">

    <xyz.sangcomz.stickytimelineview.TimeLineRecyclerView
        android:id="@+id/recycler_view"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />
</android.support.constraint.ConstraintLayout>

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        
        val recyclerView: TimeLineRecyclerView = findViewById(R.id.recycler_view)
        
        //Currently only LinearLayoutManager is supported.
        recyclerView.layoutManager = LinearLayoutManager(this,
                LinearLayoutManager.VERTICAL,
                false)

        //Get data
        val singerList = getSingerList()


        //Add RecyclerSectionItemDecoration.SectionCallback
        recyclerView.addItemDecoration(getSectionCallback(singerList))
        
        //Set Adapter
        recyclerView.adapter = SingerAdapter(layoutInflater,
                singerList,
                R.layout.recycler_row)
    }

    //Get data method
    private fun getSingerList(): List<Singer> = SingerRepo().singerList


    //Get SectionCallback method
    private fun getSectionCallback(singerList: List<Singer>): RecyclerSectionItemDecoration.SectionCallback {
        return object : RecyclerSectionItemDecoration.SectionCallback {
            //In your data, implement a method to determine if this is a section.
            override fun isSection(position: Int): Boolean =
                    singerList[position].debuted != singerList[position - 1].debuted

            //Implement a method that returns a SectionHeader.
            override fun getSectionHeader(position: Int): SectionInfo? =
                    SectionInfo(singerList[position].debuted, singerList[position].group)
        }
    }
}

<?xml version="1.0" encoding="utf-8"?>
<!--Don't set margin value in the parent view-->
<android.support.v7.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <TextView
        android:id="@+id/full_name_tv"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:padding="10dp" />

</android.support.v7.widget.CardView>