Fully documented all Kotlin files and added TODOs to functions that need to be updated in some way

app/src/main/java/com/denizk0461/studip/adapter/CanteenOfferItemAdapter.kt

@@ -2,18 +2,27 @@ package com.denizk0461.studip.adapter
 
 import android.view.LayoutInflater
 import android.view.ViewGroup
-import android.widget.ImageView
-import androidx.core.widget.ImageViewCompat
 import androidx.recyclerview.widget.RecyclerView
-import com.denizk0461.studip.data.Misc
+import com.denizk0461.studip.R
 import com.denizk0461.studip.databinding.ItemCanteenBinding
 import com.denizk0461.studip.databinding.ItemCanteenLineBinding
 import com.denizk0461.studip.databinding.ItemIconBinding
-import com.denizk0461.studip.model.CanteenOffer
 import com.denizk0461.studip.model.CanteenOfferGroup
 
-class CanteenOfferItemAdapter(private val offers: List<CanteenOfferGroup>) : RecyclerView.Adapter<CanteenOfferItemAdapter.OfferViewHolder>() {
+/**
+ * Custom RecyclerView adapter that lays out the offers of a given canteen on a given day.
+ *
+ * @param offers            list of all offers filtered by canteen and day, grouped by category
+ */
+class CanteenOfferItemAdapter(
+    private val offers: List<CanteenOfferGroup>
+) : RecyclerView.Adapter<CanteenOfferItemAdapter.OfferViewHolder>() {
 
+    /**
+     * View holder class for parent class
+     *
+     * @param binding   view binding object
+     */
     class OfferViewHolder(val binding: ItemCanteenBinding) : RecyclerView.ViewHolder(binding.root)
 
     override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): OfferViewHolder {
@@ -26,20 +35,32 @@ class CanteenOfferItemAdapter(private val offers: List<CanteenOfferGroup>) : Rec
         )
     }
 
+    // Returns the amount of offers for a given canteen and day
     override fun getItemCount(): Int = offers.size
 
+    // TODO inflate a view saying "no events" if none are available for a given day
     override fun onBindViewHolder(holder: OfferViewHolder, position: Int) {
+        // Retrieve item for current position
         val currentItem = offers[position]
 
+        // Set category text / header of the item
         holder.binding.textCategory.text = currentItem.category
 
+        // Create a new view (line) for each item displayed within one category
         currentItem.offers.forEach { offer ->
+            // Inflate the new line without binding it to the line container
             val line = ItemCanteenLineBinding.inflate(
                 LayoutInflater.from(holder.binding.root.context),
             )
 
+            // Set text values
             line.textContent.text = offer.title
             line.textPrice.text = offer.price
+
+            /*
+             * Check which dietary preferences are met by this item. This is used to set visual
+             * icons on each line. Example: a leaf on vegan items.
+             */
             val indices = arrayListOf<Int>()
             offer.dietaryPreferences.filterIndexed { index, char ->
                 if (char == 't') {
@@ -47,25 +68,44 @@ class CanteenOfferItemAdapter(private val offers: List<CanteenOfferGroup>) : Rec
                     true
                 } else false
             }
+
+            // If no dietary preferences are met, set the view to display a neutral icon
             if (indices.isEmpty()) indices.add(10)
+
+            // Iterate through all icons that need to be displayed
             indices.forEach { index ->
+                // Inflate a new icon holder
                 val img = ItemIconBinding.inflate(LayoutInflater.from(holder.binding.root.context))
-//            holder.binding.root.resources.getDrawable(Misc.indexToDrawable[index]!!, holder.binding.root.context.theme)
-                img.imageView.setImageDrawable(holder.binding.root.context.getDrawable(Misc.indexToDrawable[index]!!))
+
+                // Set the appropriate icon
+                img.imageView.setImageDrawable(
+                    holder.binding.root.context.getDrawable(indexToDrawable[index]!!)
+                )
+
+                // Bind the new icon to the line view
                 line.imageViewContainer.addView(img.root)
             }
 
+            // Bind the new line to the line container
             holder.binding.lineContainer.addView(line.root)
         }
-
-//        holder.binding.textCategory.text = currentItem.category
-//        holder.binding.tempContent.text = "${currentItem.title} • ${currentItem.price}"
-
-        // TODO inflate view saying "no offers!" or sth
     }
 
-//    interface OnClickListener {
-//        fun onClick(event: StudIPEvent)
-//        fun onLongClick(event: StudIPEvent)
-//    }
+    /**
+     * Provides a converting function between the index of a dietary preference and its according
+     * icon.
+     */
+    private val indexToDrawable: Map<Int, Int> = mapOf(
+        0 to R.drawable.handshake,
+        1 to R.drawable.fish,
+        2 to R.drawable.chicken,
+        3 to R.drawable.sheep,
+        4 to R.drawable.yoga,
+        5 to R.drawable.cow,
+        6 to R.drawable.pig,
+        7 to R.drawable.leaf,
+        8 to R.drawable.carrot,
+        9 to R.drawable.deer,
+        10 to R.drawable.circle,
+    )
 }