Expand or collapse card when clicking on it

app/src/main/java/net/underdesk/circolapp/adapters/CircularLetterAdapter.kt

@@ -31,6 +31,7 @@ import android.widget.ImageButton
 import android.widget.TextView
 import androidx.appcompat.app.AlertDialog
 import androidx.appcompat.app.AppCompatActivity
+import androidx.cardview.widget.CardView
 import androidx.core.app.ActivityCompat
 import androidx.core.content.ContextCompat
 import androidx.fragment.app.FragmentActivity
@@ -54,6 +55,7 @@ class CircularLetterAdapter(
     private var collapsedItems = -1
 
     inner class CircularLetterViewHolder(view: View) : RecyclerView.ViewHolder(view) {
+        var card: CardView = view.circular_card
         var title: TextView = view.circular_title_textview
         var number: TextView = view.circular_number_textview
         var date: TextView = view.circular_date_textview
@@ -206,6 +208,17 @@ class CircularLetterAdapter(
 
             notifyItemChanged(position)
         }
+
+        holder.card.setOnClickListener {
+            collapsedItems = if (collapsedItems == position) {
+                -1
+            } else {
+                if (collapsedItems > -1) notifyItemChanged(collapsedItems)
+                position
+            }
+
+            notifyItemChanged(position)
+        }
     }
 
     fun changeDataSet(newCirculars: List<Circular>) {

app/src/main/res/layout/item_circular.xml

@@ -1,6 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <androidx.cardview.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:app="http://schemas.android.com/apk/res-auto"
+    android:id="@+id/circular_card"
     android:layout_width="match_parent"
     android:layout_height="wrap_content"
     android:layout_marginStart="8dp"