Updated sample app to match README sample

* Updated sample app to match README sample

* Reduces gif resolution

* Added crash warning to readme

* Fixed indentation

* Explained crash

README.md

@@ -154,6 +154,17 @@ fun `when 2 of 4 registered students are attendees then student items correctly
 viewModel.adapterItems.subscribe(adapter)
 ```
 
+## Known issues
+There is an issue in androidx.recyclerview version <= 1.1.0. If you use such version then you have to override
+`LayoutManager.supportsPredictiveItemAnimations` and return false to avoid crash that may happen during list animation.
+```kotlin
+layoutManager = object : LinearLayoutManager(context, RecyclerView.VERTICAL, false) {
+    override fun supportsPredictiveItemAnimations(): Boolean {
+            return false
+        }
+    }
+}
+```
 
 ### More
 

app/build.gradle

@@ -1,5 +1,6 @@
 apply plugin: 'com.android.application'
 apply plugin: 'kotlin-android'
+apply plugin: 'kotlin-android-extensions'
 
 android {
     compileSdkVersion 29
@@ -24,7 +25,7 @@ dependencies {
     implementation 'androidx.appcompat:appcompat:1.2.0'
     implementation "androidx.cardview:cardview:1.0.0"
     implementation 'androidx.core:core-ktx:1.3.2'
-    implementation 'androidx.recyclerview:recyclerview:1.1.0'
+    implementation 'androidx.recyclerview:recyclerview:1.2.0-beta02'
     implementation 'com.google.android.material:material:1.2.1'
     implementation project(":universal-adapter")
 

app/src/main/java/com/jacekmarchwicki/changesdetector/example/MainActivity.kt

@@ -17,64 +17,96 @@ package com.jacekmarchwicki.changesdetector.example
 
 import android.os.Bundle
 import android.view.View
-import android.widget.TextView
+import android.widget.Toast
 import androidx.appcompat.app.AppCompatActivity
-import androidx.cardview.widget.CardView
 import androidx.recyclerview.widget.LinearLayoutManager
 import androidx.recyclerview.widget.RecyclerView
-import com.jacekmarchwicki.universaladapter.DefaultAdapterItem
-import com.jacekmarchwicki.universaladapter.LayoutViewHolderManager
-import com.jacekmarchwicki.universaladapter.UniversalAdapter
-import com.jacekmarchwicki.universaladapter.ViewHolderManager.BaseViewHolder
+import com.jacekmarchwicki.universaladapter.*
+import kotlinx.android.synthetic.main.item_header.view.*
+import kotlinx.android.synthetic.main.item_song.view.*
+import kotlinx.android.synthetic.main.main_activity.*
 
-class MainActivity : AppCompatActivity() {
+class MainActivity : AppCompatActivity(), MainPresenter.MainView {
 
-    private val presenter = MainPresenter()
+    private val presenter = MainPresenter(this)
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         setContentView(R.layout.main_activity)
-        val recyclerView = (findViewById<View>(R.id.main_activity_recycler) as RecyclerView).apply {
-            layoutManager = LinearLayoutManager(this@MainActivity, LinearLayoutManager.VERTICAL, false).apply {
+        val recyclerView = main_activity_recycler.apply {
+            layoutManager = object : LinearLayoutManager(this@MainActivity, RecyclerView.VERTICAL, false) {
+                // If you use androidx.recyclerview version <= 1.1.0 then you have to override this method
+                // as there is a bug that may cause a crash when the list animates
+            /*    override fun supportsPredictiveItemAnimations(): Boolean {
+                    return false
+                }*/
+            }.apply {
                 recycleChildrenOnDetach = true
             }
+
         }
 
-        val adapter = UniversalAdapter(listOf(DataViewHolder(), HeaderViewHolder()))
+        val adapter = UniversalAdapter(listOf(
+            SongViewHolder(ImageLoader()), HeaderViewHolder(), FooterViewHolder())
+        )
         recyclerView.adapter = adapter
 
-        findViewById<View>(R.id.main_activity_fab)
-                .setOnClickListener { adapter.submitList(presenter.getItems()) }
+        main_activity_fab.setOnClickListener { adapter.submitList(presenter.getItems()) }
     }
-}
 
-data class DataItem(val id: Long, val name: String, val color: Int) : DefaultAdapterItem() {
-    override val itemId: Any = id
+    override fun onSongClicked(id: String) {
+        Toast.makeText(this, "Song $id clicked", Toast.LENGTH_SHORT).show()
+    }
 }
 
-class DataViewHolder : LayoutViewHolderManager<DataItem>(
-        R.layout.data_item, DataItem::class, { ViewHolder(it) }
+// Data models
+data class HeaderItem(val text: String, val songsCount: Int, override val itemId: Any = text) : DefaultAdapterItem()
+
+data class SongItem(
+    val id: String,
+    val title: String,
+    val imageUrl: String,
+    override val itemId: Any = id,
+    val onSongClick: (id: String) -> Unit
+) : DefaultAdapterItem()
+
+data class FooterItem(override val itemId: Any = BaseAdapterItem.NO_ID) : DefaultAdapterItem()
+
+// View Holders
+class HeaderViewHolder : LayoutViewHolderManager<HeaderItem>(
+    R.layout.item_header, HeaderItem::class, { HeaderViewHolder(it) }
 ) {
-    class ViewHolder(itemView: View) : BaseViewHolder<DataItem>(itemView) {
-        override fun bind(item: DataItem) {
-            itemView.findViewById<TextView>(R.id.data_item_text).apply {
-                text = item.name
-                setOnClickListener { println("Click: $item") }
-            }
-            itemView.findViewById<CardView>(R.id.data_item_cardview)
-                    .setCardBackgroundColor(item.color)
+    class HeaderViewHolder(itemView: View) : ViewHolderManager.BaseViewHolder<HeaderItem>(itemView) {
+        override fun bind(item: HeaderItem) {
+            itemView.item_header_tv.text = "${item.text}  (songs count: ${item.songsCount})"
         }
     }
 }
 
-data class HeaderItem(val text: String, override val itemId: Any = text) : DefaultAdapterItem()
-
-class HeaderViewHolder : LayoutViewHolderManager<HeaderItem>(
-        R.layout.item_header, HeaderItem::class, { HeaderViewHolder(it) }
+class SongViewHolder(private val imageLoader: ImageLoader) : LayoutViewHolderManager<SongItem>(
+    R.layout.item_song, SongItem::class, { ViewHolder(it, imageLoader) }
 ) {
-    class HeaderViewHolder(itemView: View) : BaseViewHolder<HeaderItem>(itemView) {
-        override fun bind(item: HeaderItem) {
-            itemView.findViewById<TextView>(R.id.item_header_tv).text = item.text
+    class ViewHolder(itemView: View, private val imageLoader: ImageLoader) : ViewHolderManager.BaseViewHolder<SongItem>(itemView) {
+        override fun bind(item: SongItem) {
+            itemView.item_song_title.text = item.title
+            itemView.setOnClickListener { item.onSongClick(item.id) }
+            imageLoader.load(item.imageUrl).into(itemView.item_song_card)
         }
     }
+}
+
+class FooterViewHolder : LayoutViewHolderManager<FooterItem>(
+    R.layout.item_footer, FooterItem::class, { ViewHolder(it) }
+) {
+    class ViewHolder(itemView: View) : ViewHolderManager.BaseViewHolder<FooterItem>(itemView) {
+        override fun bind(item: FooterItem) {}
+    }
+}
+
+class ImageLoader {
+    fun load(url: String): ImageLoader {
+        return this
+    }
+
+    fun into(view: View) {}
 }

app/src/main/java/com/jacekmarchwicki/changesdetector/example/MainPresenter.kt

@@ -16,46 +16,38 @@
 
 package com.jacekmarchwicki.changesdetector.example
 
-import android.graphics.Color
 import com.jacekmarchwicki.universaladapter.BaseAdapterItem
-import java.util.*
-import kotlin.math.min
+import kotlin.random.Random
 
-class MainPresenter {
+class MainPresenter(private val view: MainView) {
+
+    interface MainView {
+        fun onSongClicked(id: String)
+    }
 
     fun getItems(): List<BaseAdapterItem> {
-        val random = Random()
-        var hue = 0f
-        val itemsCount = randomBetween(random, 10, 30)
-        val items = mutableListOf<BaseAdapterItem>()
-        for (i in 0 until itemsCount) {
-            hue += 0.12345f
-            if (!randomWithGaussianBoolean(random, 2.0)) {
-                continue
+        val albumsCount = Random.nextInt(2, 4)
+        return mutableListOf<BaseAdapterItem>().apply {
+            repeat(albumsCount) { index ->
+                val songs = getSongsForAlbum()
+                add(HeaderItem("Album $index", songsCount = songs.size, itemId = index))
+                addAll(songs)
             }
-            val realHue = hue % 1.0f
-            val color = Color.HSVToColor(255, floatArrayOf(realHue * 360, 1f, 0.5f))
-            val name = if (randomWithGaussianBoolean(random, 2.0)) "item$i" else "item$i - changed"
-            items.add(DataItem(i.toLong(), name, color))
-        }
-        val swapStart = randomBetween(random, 0, items.size - 2)
-        val swapEnd = min(items.size - 1, swapStart + 2)
-        Collections.swap(items, swapStart, swapEnd)
-
-        items.add(0, HeaderItem("Header 0"))
-        val secondPosition = itemsCount / 3
-        items.add(secondPosition, HeaderItem("Header $secondPosition"))
-        val thirdPosition = itemsCount / 2
-        items.add(thirdPosition, HeaderItem("Header $thirdPosition"))
-
-        return items.toList()
+            add(FooterItem())
+        }.toList()
     }
 
-    private fun randomWithGaussianBoolean(random: Random, proablity: Double): Boolean {
-        return Math.abs(random.nextGaussian()) < proablity
+    private fun getSongsForAlbum(): List<BaseAdapterItem> {
+        val songsCount = Random.nextInt(1, 4)
+        return mutableListOf<BaseAdapterItem>().apply {
+            repeat(songsCount) { index ->
+                add(SongItem(index.toString(), "Song $index",
+                    itemId = index, onSongClick = ::onSongClick, imageUrl = "url"))
+            }
+        }.toList()
     }
 
-    private fun randomBetween(random: Random, start: Int, end: Int): Int {
-        return random.nextInt(end - start) + start
+    private fun onSongClick(id: String) {
+        view.onSongClicked(id)
     }
 }

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

@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="utf-8"?>
+<TextView xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    android:layout_width="match_parent"
+    android:layout_height="50dp"
+    android:layout_margin="6dp"
+    android:background="#FADDE7"
+    android:gravity="center"
+    android:text="FOOTER"
+    app:fontFamily="sans-serif-medium" />

app/src/main/res/layout/data_item.xml → app/src/main/res/layout/item_song.xml

@@ -4,28 +4,25 @@
     xmlns:tools="http://schemas.android.com/tools"
     android:layout_width="match_parent"
     android:layout_height="wrap_content"
-    android:padding="2dp">
+    android:background="?selectableItemBackground">
 
     <androidx.cardview.widget.CardView
-        android:id="@+id/data_item_cardview"
+        android:id="@+id/item_song_card"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
-        app:cardBackgroundColor="#f00"
+        app:cardUseCompatPadding="true"
         app:cardCornerRadius="4dp"
         app:cardElevation="4dp">
 
-
         <TextView
-            android:id="@+id/data_item_text"
+            android:id="@+id/item_song_title"
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
             android:orientation="vertical"
             android:padding="16dp"
             android:textColor="#c1000000"
             android:textSize="16sp"
-            tools:text="ASdfasdf asdfasdf aklsdfj ">
-
-        </TextView>
+            tools:text="ASdfasdf asdfasdf aklsdfj "/>
 
     </androidx.cardview.widget.CardView>
 </FrameLayout>

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

@@ -22,6 +22,7 @@
         android:layout_height="wrap_content"
         android:layout_gravity="end|bottom"
         android:src="@drawable/ic_switch_arrows_white_24dp"
+        app:useCompatPadding="true"
         app:elevation="4dp"
         app:fabSize="normal" />
 </FrameLayout>