#88 Jetpack Paging 3 support

app/build.gradle

@@ -28,6 +28,10 @@ android {
         targetCompatibility rootProject.ext.javaTargetCompatibility
     }
 
+    kotlinOptions {
+        jvmTarget = rootProject.ext.javaSourceCompatibility.toString()
+    }
+
     lintOptions {
         disable 'GoogleAppIndexingWarning'
         abortOnError false
@@ -46,6 +50,7 @@ dependencies {
 
     implementation project(':library')
     implementation project(':paging')
+    implementation project(':paging3')
     implementation project(':kotlin-dsl')
     implementation project(':kotlin-dsl-layoutcontainer')
     implementation project(':kotlin-dsl-viewbinding')

app/src/main/AndroidManifest.xml

@@ -22,6 +22,7 @@
         <activity android:name=".animations.AnimationDiffUtilsActivity" />
         <activity android:name=".DiffActivity" />
         <activity android:name=".pagination.PaginationActivity"></activity>
+        <activity android:name=".paging3.Paging3Activity" />
     </application>
 
 </manifest>

app/src/main/java/com/hannesdorfmann/adapterdelegates4/sample/MainActivity.java

@@ -12,6 +12,7 @@
 import com.hannesdorfmann.adapterdelegates4.sample.model.Gecko;
 import com.hannesdorfmann.adapterdelegates4.sample.model.Snake;
 import com.hannesdorfmann.adapterdelegates4.sample.pagination.PaginationActivity;
+import com.hannesdorfmann.adapterdelegates4.sample.paging3.Paging3Activity;
 
 import java.util.ArrayList;
 import java.util.Collections;
@@ -63,6 +64,13 @@ public void onClick(View v) {
                 startActivity(new Intent(MainActivity.this, PaginationActivity.class));
             }
         });
+
+        findViewById(R.id.paging3).setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View view) {
+                startActivity(new Intent(MainActivity.this, Paging3Activity.class));
+            }
+        });
     }
 
     private List<DisplayableItem> getAnimals() {

app/src/main/java/com/hannesdorfmann/adapterdelegates4/sample/paging3/Paging3Activity.kt

@@ -0,0 +1,115 @@
+package com.hannesdorfmann.adapterdelegates4.sample.paging3
+
+import android.content.Context
+import android.os.Bundle
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import android.widget.TextView
+import androidx.appcompat.app.AppCompatActivity
+import androidx.lifecycle.lifecycleScope
+import androidx.paging.Pager
+import androidx.paging.PagingConfig
+import androidx.paging.cachedIn
+import androidx.recyclerview.widget.DiffUtil
+import androidx.recyclerview.widget.LinearLayoutManager
+import androidx.recyclerview.widget.RecyclerView
+import com.hannesdorfmann.adapterdelegates4.AdapterDelegate
+import com.hannesdorfmann.adapterdelegates4.AdapterItemProvider
+import com.hannesdorfmann.adapterdelegates4.paging3.PagingDelegationAdapter
+import com.hannesdorfmann.adapterdelegates4.dsl.adapterLayoutContainer
+import com.hannesdorfmann.adapterdelegates4.dsl.adapterViewBinding
+import com.hannesdorfmann.adapterdelegates4.sample.R
+import com.hannesdorfmann.adapterdelegates4.sample.databinding.ItemDogBinding
+import com.hannesdorfmann.adapterdelegates4.sample.model.Cat
+import com.hannesdorfmann.adapterdelegates4.sample.model.DisplayableItem
+import com.hannesdorfmann.adapterdelegates4.sample.model.Dog
+import com.hannesdorfmann.adapterdelegates4.sample.model.Snake
+import kotlinx.android.synthetic.main.item_snake.*
+import kotlinx.coroutines.flow.collectLatest
+import kotlinx.coroutines.launch
+
+class Paging3Activity : AppCompatActivity() {
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        setContentView(R.layout.activity_pagination)
+
+        val recyclerView: RecyclerView = findViewById(R.id.recyclerView)
+        recyclerView.layoutManager = LinearLayoutManager(this)
+
+        val adapter = PagingDelegationAdapter<DisplayableItem>(
+            callback,
+            CatAdapterDelegate(this),
+            adapterViewBinding<Dog, DisplayableItem, ItemDogBinding>(
+                viewBinding = { layoutInflater, parent ->
+                    ItemDogBinding.inflate(layoutInflater, parent, false)
+                }
+            ) {
+                bind { binding.name.text = item.name }
+            },
+            adapterLayoutContainer<Snake, DisplayableItem>(R.layout.item_snake) {
+                bind {
+                    name.text = item.name
+                    race.text = item.race
+                }
+            }
+        )
+
+        recyclerView.adapter = adapter
+
+        lifecycleScope.launch {
+            Pager<Int, DisplayableItem>(
+                PagingConfig(pageSize = 10, enablePlaceholders = false)
+            ) {
+                SampleDatasource()
+            }.flow
+                .cachedIn(lifecycleScope)
+                .collectLatest { adapter.submitData(it) }
+        }
+    }
+
+    private val callback = object : DiffUtil.ItemCallback<DisplayableItem>() {
+        override fun areItemsTheSame(oldItem: DisplayableItem, newItem: DisplayableItem): Boolean {
+            if (oldItem === newItem || oldItem == newItem) {
+                return true
+            }
+            return oldItem.javaClass == newItem.javaClass
+        }
+
+        override fun areContentsTheSame(oldItem: DisplayableItem, newItem: DisplayableItem): Boolean {
+            // TODO: implement that properly
+            return false
+        }
+
+    }
+}
+
+private class CatAdapterDelegate(
+    context: Context
+) : AdapterDelegate<AdapterItemProvider<DisplayableItem>>() {
+
+    private val layoutInflater = LayoutInflater.from(context)
+
+    override fun isForViewType(items: AdapterItemProvider<DisplayableItem>, position: Int): Boolean {
+        return items.getAdapterItem(position) is Cat
+    }
+
+    override fun onCreateViewHolder(parent: ViewGroup): RecyclerView.ViewHolder {
+        return CatViewHolder(layoutInflater.inflate(R.layout.item_cat, parent, false))
+    }
+
+    override fun onBindViewHolder(items: AdapterItemProvider<DisplayableItem>, position: Int, holder: RecyclerView.ViewHolder, payloads: MutableList<Any>) {
+        val vh = holder as CatViewHolder
+        val cat = items.getAdapterItem(position) as Cat
+
+        vh.name.text = cat.name
+    }
+
+    class CatViewHolder(
+        itemView: View
+    ) : RecyclerView.ViewHolder(itemView) {
+
+        val name: TextView = itemView.findViewById(R.id.name)
+    }
+}

app/src/main/java/com/hannesdorfmann/adapterdelegates4/sample/paging3/SampleDatasource.kt

@@ -0,0 +1,28 @@
+package com.hannesdorfmann.adapterdelegates4.sample.paging3
+
+import androidx.paging.PagingSource
+import com.hannesdorfmann.adapterdelegates4.sample.model.Cat
+import com.hannesdorfmann.adapterdelegates4.sample.model.DisplayableItem
+import com.hannesdorfmann.adapterdelegates4.sample.model.Dog
+import com.hannesdorfmann.adapterdelegates4.sample.model.Snake
+import java.lang.IllegalStateException
+import java.util.*
+
+class SampleDatasource : PagingSource<Int, DisplayableItem>() {
+
+    private val random = Random()
+
+    override suspend fun load(params: LoadParams<Int>): LoadResult<Int, DisplayableItem> {
+        val result = mutableListOf<DisplayableItem>()
+        for (i in 0 until params.loadSize) {
+            when (val itemType = random.nextInt(3)) {
+                0 -> result.add(Cat("Cat $i"))
+                1 -> result.add(Dog("Dog $i"))
+                2 -> result.add(Snake("Snake $i", "Race"))
+                else -> throw IllegalStateException("Random returned $itemType")
+            }
+        }
+
+        return LoadResult.Page(data = result, prevKey = params.key, nextKey = (params.key ?: 0) + 1)
+    }
+}

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

@@ -50,6 +50,13 @@
             android:layout_weight="1"
             android:text="Pagination" />
 
+        <Button
+            android:id="@+id/paging3"
+            android:layout_width="0dp"
+            android:layout_height="match_parent"
+            android:layout_weight="1"
+            android:text="Paging3" />
+
     </LinearLayout>
 
 </LinearLayout>

build.gradle

@@ -27,8 +27,9 @@ ext {
     androidAnnotations = 'androidx.annotation:annotation:1.0.0'
     core = 'androidx.core:core:1.0.0'
     paging = "androidx.paging:paging-runtime:2.0.0"
+    paging3 = "androidx.paging:paging-runtime:3.0.0-alpha02"
     compileSdk = 28
 
-    javaSourceCompatibility = JavaVersion.VERSION_1_7
-    javaTargetCompatibility = JavaVersion.VERSION_1_7
+    javaSourceCompatibility = JavaVersion.VERSION_1_8
+    javaTargetCompatibility = JavaVersion.VERSION_1_8
 }

kotlin-dsl-layoutcontainer/src/main/java/com/hannesdorfmann/adapterdelegates4/dsl/LayoutContainerAdapterDelegateDsl.kt

@@ -0,0 +1,90 @@
+package com.hannesdorfmann.adapterdelegates4.dsl
+
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import androidx.annotation.LayoutRes
+import androidx.recyclerview.widget.RecyclerView
+import com.hannesdorfmann.adapterdelegates4.AbsItemAdapterDelegate
+import com.hannesdorfmann.adapterdelegates4.AdapterDelegate
+import com.hannesdorfmann.adapterdelegates4.AdapterItemProvider
+
+inline fun <reified I : T, T> adapterLayoutContainer(
+    @LayoutRes layout: Int,
+    noinline on: (item: T, items: AdapterItemProvider<T>, position: Int) -> Boolean = { item, _, _ -> item is I },
+    noinline layoutInflater: (parent: ViewGroup, layoutRes: Int) -> View = { parent, layoutRes ->
+        LayoutInflater.from(parent.context).inflate(
+            layoutRes,
+            parent,
+            false
+        )
+    },
+    noinline block: AdapterDelegateLayoutContainerViewHolder<I>.() -> Unit
+): AdapterDelegate<AdapterItemProvider<T>> {
+
+    return DslLayoutContainerAdapterDelegate(
+        layout = layout,
+        on = on,
+        initializerBlock = block,
+        layoutInflater = layoutInflater
+    )
+}
+
+@PublishedApi
+internal class DslLayoutContainerAdapterDelegate<I : T, T>(
+    @LayoutRes private val layout: Int,
+    private val on: (item: T, items: AdapterItemProvider<T>, position: Int) -> Boolean,
+    private val initializerBlock: AdapterDelegateLayoutContainerViewHolder<I>.() -> Unit,
+    private val layoutInflater: (parent: ViewGroup, layoutRes: Int) -> View
+) : AbsItemAdapterDelegate<I, T, AdapterDelegateLayoutContainerViewHolder<I>>() {
+
+    override fun isForViewType(item: T, items: AdapterItemProvider<T>, position: Int): Boolean = on(
+        item, items, position
+    )
+
+    override fun onCreateViewHolder(parent: ViewGroup): AdapterDelegateLayoutContainerViewHolder<I> =
+        AdapterDelegateLayoutContainerViewHolder<I>(
+            layoutInflater(parent, layout)
+        ).also {
+            initializerBlock(it)
+        }
+
+    override fun onBindViewHolder(
+        item: I,
+        holder: AdapterDelegateLayoutContainerViewHolder<I>,
+        payloads: List<Any>
+    ) {
+        holder._item = item as Any
+        holder._bind?.invoke(payloads) // It's ok to have an AdapterDelegate without binding block (i.e. static content)
+    }
+
+    override fun onViewRecycled(holder: RecyclerView.ViewHolder) {
+        @Suppress("UNCHECKED_CAST")
+        val vh = (holder as AdapterDelegateLayoutContainerViewHolder<I>)
+
+        vh._onViewRecycled?.invoke()
+    }
+
+    override fun onFailedToRecycleView(holder: RecyclerView.ViewHolder): Boolean {
+        @Suppress("UNCHECKED_CAST")
+        val vh = (holder as AdapterDelegateLayoutContainerViewHolder<I>)
+        val block = vh._onFailedToRecycleView
+        return if (block == null) {
+            super.onFailedToRecycleView(holder)
+        } else {
+            block()
+        }
+    }
+
+    override fun onViewAttachedToWindow(holder: RecyclerView.ViewHolder) {
+        @Suppress("UNCHECKED_CAST")
+        val vh = (holder as AdapterDelegateLayoutContainerViewHolder<I>)
+        vh._onViewAttachedToWindow?.invoke()
+    }
+
+    override fun onViewDetachedFromWindow(holder: RecyclerView.ViewHolder) {
+        @Suppress("UNCHECKED_CAST")
+        val vh = (holder as AdapterDelegateLayoutContainerViewHolder<I>)
+        vh._onViewDetachedFromWindow?.invoke()
+    }
+}

kotlin-dsl-viewbinding/src/main/java/com/hannesdorfmann/adapterdelegates4/dsl/ViewBindingAdapterDelegateDsl.kt

@@ -0,0 +1,49 @@
+package com.hannesdorfmann.adapterdelegates4.dsl
+
+import android.view.LayoutInflater
+import android.view.ViewGroup
+import androidx.viewbinding.ViewBinding
+import com.hannesdorfmann.adapterdelegates4.AbsItemAdapterDelegate
+import com.hannesdorfmann.adapterdelegates4.AdapterDelegate
+import com.hannesdorfmann.adapterdelegates4.AdapterItemProvider
+
+inline fun <reified  I : T, T, V : ViewBinding> adapterViewBinding(
+    noinline viewBinding: (layoutInflater: LayoutInflater, parent: ViewGroup) -> V,
+    noinline on: (item: T, items: AdapterItemProvider<T>, position: Int) -> Boolean = { item, _, _ -> item is I},
+    noinline layoutInflater: (parent: ViewGroup) -> LayoutInflater = { parent -> LayoutInflater.from(parent.context)},
+    noinline block: AdapterDelegateViewBindingViewHolder<I, V>.() -> Unit
+): AdapterDelegate<AdapterItemProvider<T>> {
+    return DslViewBindingAdapterDelegate(
+        binding = viewBinding,
+        on = on,
+        initializerBlock = block,
+        layoutInflater = layoutInflater
+    )
+}
+
+@PublishedApi
+internal class DslViewBindingAdapterDelegate<I : T, T, V : ViewBinding>(
+    private val binding: (layoutInflater: LayoutInflater, parent: ViewGroup) -> V,
+    private val on: (item: T, items: AdapterItemProvider<T>, position: Int) -> Boolean,
+    private val initializerBlock: (AdapterDelegateViewBindingViewHolder<I, V>) -> Unit,
+    private val layoutInflater: (parent: ViewGroup) -> LayoutInflater
+) : AbsItemAdapterDelegate<I, T, AdapterDelegateViewBindingViewHolder<I, V>>() {
+
+    override fun isForViewType(item: T, items: AdapterItemProvider<T>, position: Int): Boolean = on(
+        item, items, position
+    )
+
+    override fun onCreateViewHolder(parent: ViewGroup): AdapterDelegateViewBindingViewHolder<I, V> {
+        val binding = binding(layoutInflater(parent), parent)
+        return AdapterDelegateViewBindingViewHolder<I, V>(
+            binding
+        ).also {
+            initializerBlock(it)
+        }
+    }
+
+    override fun onBindViewHolder(item: I, holder: AdapterDelegateViewBindingViewHolder<I, V>, payloads: List<Any>) {
+        holder._item = item as Any
+        holder._bind?.invoke(payloads) // It's ok to have an AdapterDelegate without binding block (i.e. static content)
+    }
+}

library/src/main/java/com/hannesdorfmann/adapterdelegates4/AbsItemAdapterDelegate.java

@@ -0,0 +1,33 @@
+package com.hannesdorfmann.adapterdelegates4;
+
+import android.view.ViewGroup;
+
+import androidx.annotation.NonNull;
+import androidx.recyclerview.widget.RecyclerView;
+
+import java.util.List;
+
+public abstract class AbsItemAdapterDelegate<I extends T, T, VH extends RecyclerView.ViewHolder>
+        extends AdapterDelegate<AdapterItemProvider<T>> {
+
+    @Override
+    protected final boolean isForViewType(@NonNull AdapterItemProvider<T> items, int position) {
+        return isForViewType(items.getAdapterItem(position), items, position);
+    }
+
+    @Override
+    protected final void onBindViewHolder(@NonNull AdapterItemProvider<T> items, int position,
+                                          @NonNull RecyclerView.ViewHolder holder, @NonNull List<Object> payloads) {
+        onBindViewHolder((I) items.getAdapterItem(position), (VH) holder, payloads);
+    }
+
+    protected abstract boolean isForViewType(@NonNull T item, @NonNull AdapterItemProvider<T> items, int position);
+
+    @NonNull
+    @Override
+    protected abstract VH onCreateViewHolder(@NonNull ViewGroup parent);
+
+    protected abstract void onBindViewHolder(@NonNull I item, @NonNull VH holder,
+                                             @NonNull List<Object> payloads);
+}
+