Fix: fixed the issue when add footer and header.

adaptiverecyclerview/src/main/java/com/devrapid/adaptiverecyclerview/AdaptiveAdapter.kt

@@ -17,24 +17,42 @@ abstract class AdaptiveAdapter<VT : ViewTypeFactory, M : IVisitable<VT>, VH : Re
     var headerEntity: M? = null
         set(value) {
             value?.let {
-                field = it
-                dataList.add(0, it)
-                notifyItemInserted(0)
+                if (field == null) {
+                    dataList.add(0, it)
+                    notifyItemInserted(0)
+                }
+                else {
+                    dataList.removeAt(0)
+                    dataList.add(0, it)
+                    notifyItemChanged(0)
+                }
             } ?: run {
-                dataList.removeAt(0)
-                notifyItemRemoved(0)
+                if (field != null) {
+                    dataList.removeAt(0)
+                    notifyItemRemoved(0)
+                }
             }
+            field = value
         }
     var footerEntity: M? = null
         set(value) {
             value?.let {
-                field = it
-                dataList.add(dataList.size, it)
-                notifyItemChanged(dataList.size)
+                if (field == null) {
+                    dataList.add(dataList.size, it)
+                    notifyItemInserted(dataList.size)
+                }
+                else {
+                    dataList.removeAt(dataList.size - 1)
+                    dataList.add(dataList.size, it)
+                    notifyItemChanged(dataList.size - 1)
+                }
             } ?: run {
-                dataList.removeAt(dataList.size)
-                notifyItemChanged(dataList.size)
+                if (field != null) {
+                    dataList.removeAt(dataList.size - 1)
+                    notifyItemRemoved(dataList.size)
+                }
             }
+            field = value
         }
     open var diffUtil: AdaptiveDiffUtil<VT, M> = MultiDiffUtil()
     open var useDiffUtilUpdate = true
@@ -76,16 +94,22 @@ abstract class AdaptiveAdapter<VT : ViewTypeFactory, M : IVisitable<VT>, VH : Re
 
     // OPTIMIZE(jieyi): 2018/12/04 There's no checking bounding.
     open fun appendList(list: MutableList<M>) {
-        val startIndex = dataList.size
+        var startIndex = dataList.size
+        if (footerEntity != null)
+            startIndex--
+        // [toMutableList()] will create a new [ArrayList].
         val newList = dataList.toMutableList().apply { addAll(startIndex, list) }
         updateList { newList }
     }
 
     open fun append(item: M) {
-        val newList = dataList.toMutableList().apply { add(item) }
+        val newList = dataList.toMutableList().apply {
+            if (footerEntity != null) add(dataList.size - 1, item) else add(item)
+        }
         updateList { newList }
     }
 
+    @Deprecated("There's some bugs with index of header and footer")
     open fun add(position: Int, item: M) {
         var size = dataList.size
         if (headerEntity != null) size--
@@ -94,18 +118,20 @@ abstract class AdaptiveAdapter<VT : ViewTypeFactory, M : IVisitable<VT>, VH : Re
         if (size <= 0) throw IndexOutOfBoundsException()
 
         val newList = dataList.toMutableList().apply {
-            add(position + (if (headerEntity == null) 0 else 1), item)
+            add(position + (if (headerEntity == null) 0 else 1) + (if (footerEntity == null) 0 else -1), item)
         }
         updateList { newList }
     }
 
+    @Deprecated("There's some bugs with index of header and footer")
     open fun add(position: Int, list: MutableList<M>) {
         val newList = dataList.toMutableList().apply {
-            addAll(position + (if (headerEntity == null) 0 else 1), list)
+            addAll(position + (if (headerEntity == null) 0 else 1) + (if (footerEntity == null) 0 else -1), list)
         }
         updateList { newList }
     }
 
+    @Deprecated("There's some bugs with index of header and footer")
     open fun dropList(startIndex: Int, endIndex: Int) {
         when {
             startIndex < 0 || endIndex >= dataList.size -> throw IndexOutOfBoundsException("The range is over than list.")
@@ -117,7 +143,10 @@ abstract class AdaptiveAdapter<VT : ViewTypeFactory, M : IVisitable<VT>, VH : Re
         updateList { newList }
     }
 
-    open fun dropAt(index: Int) = dropList(index, index)
+    @Deprecated("There's some bugs with index of header and footer")
+    open fun dropAt(index: Int) {
+        dropList(index, index)
+    }
 
     open fun clearList(header: Boolean = true, footer: Boolean = true): Boolean {
         var from = 0
@@ -129,6 +158,8 @@ abstract class AdaptiveAdapter<VT : ViewTypeFactory, M : IVisitable<VT>, VH : Re
             from++
         if (!footer && headerEntity != null)
             to--
+        if (header) headerEntity = null
+        if (footer) footerEntity = null
 
         dropList(from, to)
 
@@ -137,6 +168,8 @@ abstract class AdaptiveAdapter<VT : ViewTypeFactory, M : IVisitable<VT>, VH : Re
 
     open fun replaceWholeList(newList: MutableList<M>) {
         updateList { newList }
+        headerEntity = null
+        footerEntity = null
     }
 
     private fun updateList(getNewListBlock: () -> MutableList<M>) {

build.gradle

@@ -9,7 +9,7 @@ buildscript {
         jcenter()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.3.0'
+        classpath 'com.android.tools.build:gradle:3.3.1'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
 
         // NOTE: Do not place your application dependencies here; they belong

sample/src/main/java/com/devrapid/example/ExpandAdapter.kt

@@ -9,20 +9,23 @@ import com.devrapid.example.viewtype.MultiTypeFactory
  * @author  jieyi
  * @since   9/7/17
  */
-class ExpandAdapter(override var dataList: MutableList<IExpandVisitor>):
+class ExpandAdapter(override var dataList: MutableList<IExpandVisitor>) :
     AdaptiveAdapter<MultiTypeFactory, IExpandVisitor, AdaptiveViewHolder<MultiTypeFactory, IExpandVisitor>>() {
     override var typeFactory: MultiTypeFactory = MultiTypeFactory()
     //    override var useDiffUtilUpdate = false
     private val originalParentPosition: MutableList<Int> = MutableList(this.dataList.size) { 0 }
 
-    class ExpandDiffUtil(private var oldList: MutableList<IExpandVisitor>,
-                         private var newList: MutableList<IExpandVisitor>): DiffUtil.Callback() {
+    class ExpandDiffUtil(
+        private var oldList: MutableList<IExpandVisitor>,
+        private var newList: MutableList<IExpandVisitor>
+    ) : DiffUtil.Callback() {
         override fun getOldListSize(): Int = this.oldList.size
 
         override fun getNewListSize(): Int = newList.size
 
         override fun areItemsTheSame(oldItemPosition: Int, newItemPosition: Int): Boolean =
             this.oldList[oldItemPosition].hashCode() == this.newList[newItemPosition].hashCode()
+//            (this.oldList[oldItemPosition] as Person).name == (this.newList[newItemPosition] as Person).name
 
         override fun areContentsTheSame(oldItemPosition: Int, newItemPosition: Int): Boolean = true
     }

sample/src/main/java/com/devrapid/example/MainActivity.kt

@@ -31,16 +31,14 @@ class MainActivity : AppCompatActivity() {
         recyclerView.layoutManager = LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false)
         recyclerView.adapter = adapter
 
+        adapter.headerEntity = Person("Google @@@@@@@@")
+        adapter.footerEntity = Person("Google !!!!!!!!")
+
         btn_add.setOnClickListener {
-            adapter.appendList(listOf(Person("Google $a")) as MutableList<IExpandVisitor>)
-            a++
+            adapter.clearList(false, false)
         }
         btn_minus.setOnClickListener {
-            adapter.dropList(1, 1)
-        }
-        btn_minus.setOnLongClickListener {
-            adapter.clearList()
-            true
+            adapter.append(Person("BBBBBBBB ${a++}"))
         }
     }
 }

sample/src/main/java/com/devrapid/example/viewholder/FirstViewHolder.kt

@@ -1,6 +1,7 @@
 package com.devrapid.example.viewholder
 
 import android.view.View
+import com.devrapid.adaptiverecyclerview.AdaptiveAdapter
 import com.devrapid.adaptiverecyclerview.AdaptiveViewHolder
 import com.devrapid.example.ExpandAdapter
 import com.devrapid.example.model.Person
@@ -13,7 +14,7 @@ import kotlinx.android.synthetic.main.item_first.view.tv_title
  * @since   9/6/17
  */
 class FirstViewHolder(view: View): AdaptiveViewHolder<MultiTypeFactory, Person>(view) {
-    override fun initView(model: Person, position: Int, adapter: Any) {
+    override fun initView(model: Person, position: Int, adapter: AdaptiveAdapter<*, *, *>) {
         adapter as ExpandAdapter
         this.itemView.tv_title.text = model.name
         this.itemView.btn.setOnClickListener {
@@ -26,4 +27,4 @@ class FirstViewHolder(view: View): AdaptiveViewHolder<MultiTypeFactory, Person>(
             }
         }
     }
-}
+}

sample/src/main/java/com/devrapid/example/viewholder/SecondViewHolder.kt

@@ -1,6 +1,7 @@
 package com.devrapid.example.viewholder
 
 import android.view.View
+import com.devrapid.adaptiverecyclerview.AdaptiveAdapter
 import com.devrapid.adaptiverecyclerview.AdaptiveViewHolder
 import com.devrapid.example.ExpandAdapter
 import com.devrapid.example.model.Animal
@@ -12,8 +13,8 @@ import kotlinx.android.synthetic.main.item_second.view.tv_subtitle
  * @since   9/6/17
  */
 class SecondViewHolder(view: View): AdaptiveViewHolder<MultiTypeFactory, Animal>(view) {
-    override fun initView(model: Animal, position: Int, adapter: Any) {
+    override fun initView(model: Animal, position: Int, adapter: AdaptiveAdapter<*, *, *>) {
         adapter as ExpandAdapter
         this.itemView.tv_subtitle.text = model.name
     }
-}
+}