Add a List Header in RecyclerView

ChaMinZi · Jun 8, 2021 · f9fcf6c · f9fcf6c
1 parent 1ec3c45
commit f9fcf6c
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Showing 2 changed files with 75 additions and 12 deletions.
diff --git a/...p/src/main/java/com/example/android/trackmysleepquality/sleeptracker/SleepNightAdapter.kt b/...p/src/main/java/com/example/android/trackmysleepquality/sleeptracker/SleepNightAdapter.kt
@@ -1,27 +1,67 @@
 package com.example.android.trackmysleepquality.sleeptracker
 
+import android.graphics.Color
 import android.view.LayoutInflater
+import android.view.View
 import android.view.ViewGroup
 import androidx.recyclerview.widget.DiffUtil
 import androidx.recyclerview.widget.ListAdapter
 import androidx.recyclerview.widget.RecyclerView
 import com.example.android.trackmysleepquality.R
+import com.example.android.trackmysleepquality.TextItemViewHolder
 import com.example.android.trackmysleepquality.convertDurationToFormatted
 import com.example.android.trackmysleepquality.convertNumericQualityToString
 import com.example.android.trackmysleepquality.database.SleepNight
 import com.example.android.trackmysleepquality.databinding.ListItemSleepNightBinding
 import com.example.android.trackmysleepquality.generated.callback.OnClickListener
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.withContext
 
-class SleepNightAdapter(private val clickListener:SleepNightListener) : ListAdapter<SleepNight,
-        SleepNightAdapter.ViewHolder>(SleepNightDiffCallback()) {
+private const val ITEM_VIEW_TYPE_HEADER = 0
+private const val ITEM_VIEW_TYPE_ITEM = 1
+
+class SleepNightAdapter(private val clickListener:SleepNightListener) : ListAdapter<DataItem,
+        RecyclerView.ViewHolder>(SleepNightDiffCallback()) {
+
+    private val adapterScope = CoroutineScope(Dispatchers.Default)
 
     // ViewHolder 만 변경해서 다른 로직으로 바꿀 수 있게 캡슐화 됨
-    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
-        return ViewHolder.from(parent)
+    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
+        return when(viewType) {
+            ITEM_VIEW_TYPE_HEADER -> TextViewHolder.from(parent)
+            ITEM_VIEW_TYPE_ITEM -> ViewHolder.from(parent)
+            else -> throw ClassCastException("Unknown viewType $viewType")
+        }
+    }
+
+    override fun getItemViewType(position: Int): Int {
+        return when (getItem(position)) {
+            is DataItem.Header -> ITEM_VIEW_TYPE_HEADER
+            is DataItem.SleepNightItem -> ITEM_VIEW_TYPE_ITEM
+        }
     }
 
-    override fun onBindViewHolder(holder: ViewHolder, position: Int) {
-        holder.bind(getItem(position)!!, clickListener)
+    override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {
+        when (holder) {
+            is ViewHolder -> {
+                val nightItem = getItem(position) as DataItem.SleepNightItem
+                holder.bind(nightItem.sleepNight!!, clickListener)
+            }
+        }
+    }
+
+    fun addHeaderANdSubmitList(list: List<SleepNight>?) {
+        adapterScope.launch {
+            val items = when (list) {
+                null -> listOf(DataItem.Header)
+                else -> listOf(DataItem.Header) + list.map { DataItem.SleepNightItem(it) }
+            }
+            withContext(Dispatchers.Main) {
+                submitList(items)
+            }
+        }
     }
 
     /**
@@ -51,12 +91,12 @@ class SleepNightAdapter(private val clickListener:SleepNightListener) : ListAdap
  *
  * ListAdapter 는 new Item 과 old Item이 얼마나 변했는지 최소 개수를 알아내기 위해 사용
 **/
-class SleepNightDiffCallback : DiffUtil.ItemCallback<SleepNight>() {
-    override fun areItemsTheSame(oldItem: SleepNight, newItem: SleepNight): Boolean {
-        return oldItem.nightId == newItem.nightId
+class SleepNightDiffCallback : DiffUtil.ItemCallback<DataItem>() {
+    override fun areItemsTheSame(oldItem: DataItem, newItem: DataItem): Boolean {
+        return oldItem.id == newItem.id
     }
 
-    override fun areContentsTheSame(oldItem: SleepNight, newItem: SleepNight): Boolean {
+    override fun areContentsTheSame(oldItem: DataItem, newItem: DataItem): Boolean {
         return oldItem == newItem
     }
 }
@@ -70,4 +110,27 @@ class SleepNightDiffCallback : DiffUtil.ItemCallback<SleepNight>() {
  **/
 class SleepNightListener(val clickListener: (sleepId: Long) -> Unit) {
     fun onClick(night: SleepNight) = clickListener(night.nightId)
-}
+}
+
+sealed class DataItem {
+    data class SleepNightItem(val sleepNight: SleepNight): DataItem() {
+        override val id = sleepNight.nightId
+    }
+
+    object Header: DataItem() {
+        override val id = Long.MIN_VALUE
+    }
+
+    abstract val id: Long
+}
+
+class TextViewHolder(view: View): RecyclerView.ViewHolder(view) {
+    companion object {
+        fun from(parent: ViewGroup): TextViewHolder {
+            val layoutInflater = LayoutInflater.from(parent.context)
+            val view = layoutInflater.inflate(R.layout.header, parent, false)
+            view.setBackgroundColor(Color.LTGRAY)
+            return TextViewHolder(view)
+        }
+    }
+}
diff --git a/...rc/main/java/com/example/android/trackmysleepquality/sleeptracker/SleepTrackerFragment.kt b/...rc/main/java/com/example/android/trackmysleepquality/sleeptracker/SleepTrackerFragment.kt
@@ -67,7 +67,7 @@ class SleepTrackerFragment : Fragment() {
 
         sleepTrackerViewModel.nights.observe(viewLifecycleOwner, Observer {
             it?.let {
-                adapter.submitList(it)
+                adapter.addHeaderANdSubmitList(it)
             }
         })