Simple Recyclerview

Simple RecyclerView

There are mainly 4 steps:

Add RecyclerView (View) in your Activity/Fragment XML
Create the XML file for item of recyclerView will showup
Create an RecyclerView Adapter
Call that Adapter from your Activity/Fragment

I will show you how we write code step by step. Here I am giving example of Person name RecyclerView. Also the example is of Activity.

Step 1:

Add RecyclerView widget.

activity_person.xml

...
<androidx.recyclerview.widget.RecyclerView
      android:id="@+id/rvPerson"
      android:orientation="vertical"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:focusable="true" />
...

Step 2:

Create new XML for a item for recyclerview like:

item_person.xml

<androidx.constraintlayout.widget.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="64dp"
      android:clickable="true"
      android:focusable="true">

      <TextView
      android:id="@+id/tvFullName"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="@string/app_name"/>
</ConstraintLayout>

Step 3:

Create a RecyclerView Adapter. Here we need to override onCreateViewHolder(), onBindViewHolder() and getItemCount() functions

PersonAdapter.kt

class PersonAdapter(
    var context: Context,
    private var data: List<String>,
) : RecyclerView.Adapter<PersonAdapter.PersonViewHolder>() {

      private val inflater: LayoutInflater = LayoutInflater.from(context)

      override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): PersonViewHolder {
            val view = inflater.inflate(R.layout.item_person, parent, false)
            return PersonViewHolder(view)
      }

      override fun onBindViewHolder(holder: PersonViewHolder, position: Int) {
            val personItem: String = data[position]
            tvFullName.text = personItem // textview of item_person.xml
      }

      override fun getItemCount() = data.size

      // Inner class for 
      inner class PersonViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView)
}

Step 4:

Finally, In the Activity file create instance of PersonAdapter. NOTE: Here I have created a List. You can get list from Local DB or from API.

PersonActiviy.kt

val personList = mutableListOf<String>("person1", "person2", "person3")

val adapter = PersonAdapter(this, personList)
rvPerson.adapter = adapter // rvPerson is recyclerview from activity_person.xml
rvPerson.layoutManager = LinearLayoutManager(this)

Thats it.

Simple Recyclerview