Feature: added the diff tool into adapter. Also, you can custom the d…

…iff util into.

adaptiverecyclerview/build.gradle

@@ -22,8 +22,8 @@ android {
 dependencies {
     implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8:$kotlin_version"
 
-    implementation 'androidx.appcompat:appcompat:1.0.0-alpha3'
-    implementation 'androidx.recyclerview:recyclerview:1.0.0-alpha3'
+    implementation 'androidx.appcompat:appcompat:1.0.0-rc02'
+    implementation 'androidx.recyclerview:recyclerview:1.0.0-rc02'
 }
 repositories {
     mavenCentral()

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

@@ -3,6 +3,7 @@ package com.devrapid.adaptiverecyclerview
 import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
+import androidx.recyclerview.widget.DiffUtil
 import androidx.recyclerview.widget.RecyclerView
 
 /**
@@ -35,41 +36,70 @@ abstract class AdaptiveAdapter<VT : ViewTypeFactory, M : IVisitable<VT>, VH : Re
                 notifyItemChanged(dataList.size)
             }
         }
+    open var diffUtil: AdaptiveDiffUtil<VT, M> = MultiDiffUtil()
+
     protected abstract var typeFactory: VT
     protected abstract var dataList: MutableList<M>
 
+    inner class MultiDiffUtil : AdaptiveDiffUtil<VT, M>() {
+        override var oldList = mutableListOf<M>()
+        override var newList = mutableListOf<M>()
+
+        override fun getOldListSize() = oldList.size
+
+        override fun getNewListSize() = newList.size
+
+        override fun areItemsTheSame(oldItemPosition: Int, newItemPosition: Int) =
+            oldList[oldItemPosition].hashCode() == newList[newItemPosition].hashCode()
+
+        override fun areContentsTheSame(oldItemPosition: Int, newItemPosition: Int) = true
+    }
+
     //region Necessary override methods.
-    override fun getItemCount(): Int = this.dataList.size
+    override fun getItemCount(): Int = dataList.size
 
-    override fun getItemViewType(position: Int): Int = this.dataList[position].type(this.typeFactory)
+    override fun getItemViewType(position: Int): Int = dataList[position].type(typeFactory)
 
     override fun onBindViewHolder(holder: VH, position: Int) =
-        (holder as AdaptiveViewHolder<VT, M>).initView(this.dataList[position], position, this)
+        (holder as AdaptiveViewHolder<VT, M>).initView(dataList[position], position, this)
 
     override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): VH {
         val itemView: View =
-            LayoutInflater.from(parent.context).inflate(this.typeFactory.getLayoutResource(viewType), parent, false)
+            LayoutInflater.from(parent.context).inflate(typeFactory.getLayoutResource(viewType), parent, false)
 
-        return this.typeFactory.createViewHolder(viewType, itemView) as VH
+        return typeFactory.createViewHolder(viewType, itemView) as VH
     }
     //endregion
 
-    fun appendList(list: MutableList<M>) {
+    open fun appendList(list: MutableList<M>) {
         val startIndex = dataList.size
-
-        dataList.addAll(startIndex, list)
-        notifyItemRangeChanged(startIndex, list.size)
+        val newList = dataList.toMutableList().apply { addAll(startIndex, list) }
+//        notifyItemRangeChanged(startIndex, list.size)
+        updateList { newList }
     }
 
-    fun dropList(startIndex: Int, endIndex: Int) {
+    open fun dropList(startIndex: Int, endIndex: Int) {
         when {
             startIndex < 0 || endIndex >= dataList.size -> throw IndexOutOfBoundsException("The range is over than list.")
             startIndex > endIndex -> throw IndexOutOfBoundsException("startIndex index must be less than endIndex index.")
         }
+        val newList = dataList.toMutableList()
 
-        repeat(endIndex - startIndex + 1) { dataList.removeAt(startIndex) }
-        notifyDataSetChanged()
+        repeat(endIndex - startIndex + 1) { newList.removeAt(startIndex) }
+//        notifyDataSetChanged()
+        updateList { newList }
     }
 
-    fun clearList() = dropList(0, dataList.size - 1)
+    open fun clearList() = dropList(0, dataList.size - 1)
+
+    private fun updateList(getNewListBlock: () -> MutableList<M>) {
+        val newList = getNewListBlock()
+        val res = DiffUtil.calculateDiff(diffUtil.apply {
+            oldList = dataList
+            this.newList = newList
+        }, true)
+
+        dataList = newList
+        res.dispatchUpdatesTo(this)
+    }
 }

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

@@ -0,0 +1,8 @@
+package com.devrapid.adaptiverecyclerview
+
+import androidx.recyclerview.widget.DiffUtil
+
+abstract class AdaptiveDiffUtil<VT : ViewTypeFactory, M : IVisitable<VT>> : DiffUtil.Callback() {
+    abstract var oldList: MutableList<M>
+    abstract var newList: MutableList<M>
+}

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

@@ -5,28 +5,42 @@ import androidx.appcompat.app.AppCompatActivity
 import androidx.recyclerview.widget.LinearLayoutManager
 import com.devrapid.example.model.Animal
 import com.devrapid.example.model.Person
+import kotlinx.android.synthetic.main.activity_main.btn_add
+import kotlinx.android.synthetic.main.activity_main.btn_minus
+import kotlinx.android.synthetic.main.activity_main.recyclerView
 
-class MainActivity: AppCompatActivity() {
+class MainActivity : AppCompatActivity() {
+    var a = 1
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         setContentView(R.layout.activity_main)
 
         val itemList: MutableList<IExpandVisitor> = mutableListOf(Person("Google"),
-            Person("Facebook", listOf(Animal("CEO"),
-                Animal("CTO"),
-                Animal("CDO"),
-                Animal("CAO"),
-                Animal("COO")), true),
-            Person("Apple", listOf(Animal("AEO"),
-                Animal("ATO"),
-                Animal("ADO")), true),
-            Person("Airbnb"),
-            Person("Jieyi"))
+                                                                  Person("Facebook", listOf(Animal("CEO"),
+                                                                                            Animal("CTO"),
+                                                                                            Animal("CDO"),
+                                                                                            Animal("CAO"),
+                                                                                            Animal("COO")), true),
+                                                                  Person("Apple", listOf(Animal("AEO"),
+                                                                                         Animal("ATO"),
+                                                                                         Animal("ADO")), true),
+                                                                  Person("Airbnb"),
+                                                                  Person("Jieyi"))
 
-        recyclerView.layoutManager =
-            androidx.recyclerview.widget.LinearLayoutManager(this,
-                                                             androidx.recyclerview.widget.LinearLayoutManager.VERTICAL,
-                                                             false)
-        recyclerView.adapter = ExpandAdapter(itemList)
+        val adapter = ExpandAdapter(itemList)
+        recyclerView.layoutManager = LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false)
+        recyclerView.adapter = adapter
+
+        btn_add.setOnClickListener {
+            adapter.appendList(listOf(Person("Google $a")) as MutableList<IExpandVisitor>)
+            a++
+        }
+        btn_minus.setOnClickListener {
+            adapter.dropList(1, 1)
+        }
+        btn_minus.setOnLongClickListener {
+            adapter.clearList()
+            true
+        }
     }
 }

sample/src/main/res/layout/activity_main.xml

@@ -21,4 +21,20 @@
         app:layout_constraintTop_toTopOf="parent"
         tools:layout_editor_absoluteX="8dp"
         tools:layout_editor_absoluteY="8dp"/>
+
+    <Button
+        android:id="@+id/btn_add"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:text="ADD"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintEnd_toEndOf="parent"/>
+
+    <Button
+        android:id="@+id/btn_minus"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:text="MINUS"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintEnd_toStartOf="@id/btn_add"/>
 </androidx.constraintlayout.widget.ConstraintLayout>