V3 paging loadstate

app/build.gradle

@@ -54,7 +54,7 @@ dependencies {
     implementation 'androidx.lifecycle:lifecycle-runtime-ktx:2.3.1'
     implementation 'androidx.lifecycle:lifecycle-extensions:2.2.0'
     implementation 'androidx.lifecycle:lifecycle-viewmodel-ktx:2.3.1'
-    implementation 'androidx.paging:paging-runtime-ktx:2.1.2'
+    implementation 'androidx.paging:paging-runtime-ktx:3.0.0-beta03'
 
     kapt "androidx.databinding:databinding-compiler:$agp_version"
 }

app/src/main/java/me/tatarka/bindingcollectionadapter/sample/FragmentPagedV3RecyclerView.kt

@@ -0,0 +1,32 @@
+package me.tatarka.bindingcollectionadapter.sample
+
+import android.os.Bundle
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import androidx.fragment.app.Fragment
+import androidx.lifecycle.ViewModelProviders
+import androidx.lifecycle.get
+import me.tatarka.bindingcollectionadapter.sample.databinding.PagedV3RecyclerViewBinding
+
+class FragmentPagedV3RecyclerView : Fragment() {
+    private lateinit var viewModel: ImmutableViewModel
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        viewModel = ViewModelProviders.of(this).get()
+    }
+
+    override fun onCreateView(
+        inflater: LayoutInflater,
+        container: ViewGroup?,
+        savedInstanceState: Bundle?
+    ): View? {
+        return PagedV3RecyclerViewBinding.inflate(inflater, container, false).also {
+            it.setLifecycleOwner(this)
+            it.viewModel = viewModel
+            it.listeners = viewModel
+            it.executePendingBindings()
+        }.root
+    }
+}

app/src/main/java/me/tatarka/bindingcollectionadapter/sample/ImmutableViewModel.kt

@@ -1,76 +1,123 @@
 package me.tatarka.bindingcollectionadapter.sample
 
-import androidx.lifecycle.LiveData
-import androidx.lifecycle.MutableLiveData
-import androidx.lifecycle.Transformations
-import androidx.lifecycle.ViewModel
-import androidx.paging.DataSource
-import androidx.paging.LivePagedListBuilder
-import androidx.paging.PagedList
-import androidx.paging.PositionalDataSource
+import androidx.lifecycle.*
+import androidx.paging.*
 import androidx.recyclerview.widget.DiffUtil
+import kotlinx.coroutines.delay
+import me.tatarka.bindingcollectionadapter2.ItemBinding
+import me.tatarka.bindingcollectionadapter2.itembindings.OnItemBindLoadState
 import me.tatarka.bindingcollectionadapter2.itemBindingOf
 import me.tatarka.bindingcollectionadapter2.itembindings.OnItemBindClass
 import me.tatarka.bindingcollectionadapter2.map
 import me.tatarka.bindingcollectionadapter2.toItemBinding
-import java.util.*
+import kotlin.random.Random
 
 class ImmutableViewModel : ViewModel(), ImmutableListeners {
 
     private val mutList = MutableLiveData<List<ImmutableItem>>().apply {
         value = (0 until 3).map { i -> ImmutableItem(index = i, checked = false) }
     }
     private val headerFooterList =
-        Transformations.map<List<ImmutableItem>, List<Any>>(mutList) { input ->
-            val list = ArrayList<Any>(input.size + 2)
-            list.add("Header")
-            list.addAll(input)
-            list.add("Footer")
-            list
-        }
+            Transformations.map<List<ImmutableItem>, List<Any>>(mutList) { input ->
+                val list = ArrayList<Any>(input.size + 2)
+                list.add("Header")
+                list.addAll(input)
+                list.add("Footer")
+                list
+            }
     val list: LiveData<List<Any>> = headerFooterList
 
     val pagedList: LiveData<PagedList<Any>> =
-        LivePagedListBuilder(object : DataSource.Factory<Int, Any>() {
-            override fun create(): DataSource<Int, Any> =
-                object : PositionalDataSource<Any>() {
-
-                    override fun loadInitial(
-                        params: LoadInitialParams,
-                        callback: LoadInitialCallback<Any>
-                    ) {
-                        val list =
-                            (0 until params.requestedLoadSize).map {
-                                ImmutableItem(
-                                    index = it + params.requestedStartPosition,
-                                    checked = false
-                                )
+            LivePagedListBuilder(object : DataSource.Factory<Int, Any>() {
+                override fun create(): DataSource<Int, Any> =
+                        object : PositionalDataSource<Any>() {
+
+                            override fun loadInitial(
+                                    params: LoadInitialParams,
+                                    callback: LoadInitialCallback<Any>
+                            ) {
+                                val list =
+                                        (0 until params.requestedLoadSize).map {
+                                            ImmutableItem(
+                                                    index = it + params.requestedStartPosition,
+                                                    checked = false
+                                            )
+                                        }
+                                // Pretend we are slow
+                                Thread.sleep(1000)
+                                callback.onResult(list, params.requestedStartPosition, 200)
                             }
-                        // Pretend we are slow
-                        Thread.sleep(1000)
-                        callback.onResult(list, params.requestedStartPosition, 200)
-                    }
-
-                    override fun loadRange(
-                        params: LoadRangeParams,
-                        callback: LoadRangeCallback<Any>
-                    ) {
-                        val list =
-                            (0 until params.loadSize).map {
-                                ImmutableItem(
-                                    index = it + params.startPosition,
-                                    checked = false
-                                )
+
+                            override fun loadRange(
+                                    params: LoadRangeParams,
+                                    callback: LoadRangeCallback<Any>
+                            ) {
+                                val list =
+                                        (0 until params.loadSize).map {
+                                            ImmutableItem(
+                                                    index = it + params.startPosition,
+                                                    checked = false
+                                            )
+                                        }
+                                // Pretend we are slow
+                                Thread.sleep(1000)
+                                callback.onResult(list)
                             }
-                        // Pretend we are slow
-                        Thread.sleep(1000)
-                        callback.onResult(list)
-                    }
+                        }
+            }, PAGE_SIZE).build()
+
+    val pagedListV3: LiveData<PagingData<Any>> = Pager<Int, Any>(PagingConfig(
+            pageSize = PAGE_SIZE,
+            maxSize = 100,
+            prefetchDistance = PAGE_SIZE * 2,
+            enablePlaceholders = false)) {
+        object : PagingSource<Int, Any>() {
+            private val random = Random(TOTAL_COUNT)
+
+            override suspend fun load(params: LoadParams<Int>): LoadResult<Int, Any> {
+                val safeKey = params.key ?: 0
+                val list =
+                        (0 until params.loadSize).map {
+                            ImmutableItem(
+                                    index = it + safeKey,
+                                    checked = false
+                            )
+                        }
+                // Pretend we are slow
+                delay(1000)
+
+                if (random.nextBoolean()) {
+                    return LoadResult.Error(IllegalAccessError("Error plz try again"))
                 }
-        }, 20).build()
+
+                return LoadResult.Page(
+                        data = list,
+                        prevKey = if (safeKey == 0) null else (safeKey - params.loadSize),
+                        nextKey = if (safeKey >= TOTAL_COUNT - params.loadSize) null else (safeKey + params.loadSize),
+                        itemsBefore = safeKey,
+                        itemsAfter = TOTAL_COUNT - params.loadSize - safeKey
+                )
+            }
+
+            override fun getRefreshKey(state: PagingState<Int, Any>): Int = 0
+        }
+    }.flow.asLiveData()
 
     val items = itemBindingOf<Any>(BR.item, R.layout.item_immutable)
 
+    val loadStateItems = OnItemBindLoadState.Builder<Any>()
+            .item(BR.item, R.layout.item_immutable)
+            .headerLoadState(OnItemBindClass<LoadState>().apply {
+                map<LoadState.Loading>(ItemBinding.VAR_NONE, R.layout.network_state_item_progress)
+                map<LoadState.Error>(BR.item, R.layout.network_state_item_error)
+            })
+            .footerLoadState(OnItemBindClass<LoadState>().apply {
+                map<LoadState.Loading>(ItemBinding.VAR_NONE, R.layout.network_state_item_progress)
+                map<LoadState.Error>(BR.item, R.layout.network_state_item_error)
+            })
+            .pagingCallbackVariableId(BR.callback)
+            .build()
+
     val multipleItems = OnItemBindClass<Any>().apply {
         map<String>(BR.item, R.layout.item_header_footer)
         map<ImmutableItem>(BR.item, R.layout.item_immutable)
@@ -108,4 +155,9 @@ class ImmutableViewModel : ViewModel(), ImmutableListeners {
             }
         }
     }
+
+    companion object {
+        private val TOTAL_COUNT = 200
+        private val PAGE_SIZE = 20
+    }
 }

app/src/main/java/me/tatarka/bindingcollectionadapter/sample/MainActivity.kt

@@ -40,6 +40,7 @@ class MainActivity : AppCompatActivity() {
                 R.id.action_recyclerview -> FragmentRecyclerView()
                 R.id.action_diff_recyclerview -> FragmentDiffRecyclerView()
                 R.id.action_paged_recyclerview -> FragmentPagedRecyclerView()
+                R.id.action_paged_v3_recyclerview -> FragmentPagedV3RecyclerView()
                 R.id.action_viewpager -> FragmentViewPagerView()
                 R.id.action_viewpager2 -> FragmentViewPager2View()
                 R.id.action_spinner -> FragmentSpinnerView()

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

@@ -0,0 +1,54 @@
+<?xml version="1.0" encoding="utf-8"?><!--
+  ~ Copyright (C) 2017 The Android Open Source Project
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~      http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+
+<layout xmlns:android="http://schemas.android.com/apk/res/android">
+
+    <data>
+
+        <variable
+            name="item"
+            type="me.tatarka.bindingcollectionadapter2.itembindings.Load" />
+
+        <variable
+            name="callback"
+            type="me.tatarka.bindingcollectionadapter2.PagedDataCallback" />
+
+    </data>
+
+    <LinearLayout
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:orientation="vertical"
+        android:padding="8dp">
+
+        <TextView
+            android:id="@+id/error_msg"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_gravity="center_horizontal"
+            android:text="@{item.error.message}"/>
+
+        <Button
+            android:id="@+id/retry_button"
+            style="@style/Widget.AppCompat.Button.Colored"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_gravity="center"
+            android:text="@string/retry"
+            android:onClick="@{() -> callback.retry()}"/>
+    </LinearLayout>
+
+</layout>

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

@@ -0,0 +1,34 @@
+<?xml version="1.0" encoding="utf-8"?><!--
+  ~ Copyright (C) 2017 The Android Open Source Project
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~      http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+
+<layout xmlns:android="http://schemas.android.com/apk/res/android">
+
+    <LinearLayout
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:orientation="vertical"
+        android:padding="8dp">
+
+        <ProgressBar
+            android:id="@+id/progress_bar"
+            style="?android:attr/progressBarStyle"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:layout_gravity="center" />
+
+    </LinearLayout>
+
+</layout>

app/src/main/res/layout/paged_v3_recycler_view.xml

@@ -0,0 +1,33 @@
+<?xml version="1.0" encoding="utf-8"?>
+<layout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto">
+
+    <data>
+
+        <import type="me.tatarka.bindingcollectionadapter.sample.ImmutableItem" />
+
+        <variable
+            name="viewModel"
+            type="me.tatarka.bindingcollectionadapter.sample.ImmutableViewModel" />
+
+        <variable
+            name="listeners"
+            type="me.tatarka.bindingcollectionadapter.sample.Listeners" />
+    </data>
+
+    <LinearLayout
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:orientation="vertical">
+
+        <androidx.recyclerview.widget.RecyclerView
+            android:id="@+id/list"
+            android:layout_width="match_parent"
+            android:layout_height="0dp"
+            android:layout_weight="1"
+            app:diffConfig="@{viewModel.diff}"
+            app:itemBinding="@{viewModel.loadStateItems}"
+            app:items="@{viewModel.pagedListV3}"
+            app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager" />
+    </LinearLayout>
+</layout>

app/src/main/res/menu/menu_drawer.xml

@@ -17,6 +17,11 @@
         android:id="@+id/action_paged_recyclerview"
         android:title="Paged RecyclerView" />
 
+    <item
+        android:id="@+id/action_paged_v3_recyclerview"
+        android:title="Paged V3 RecyclerView" />
+
+
     <item
         android:id="@+id/action_viewpager"
         android:title="ViewPager" />

app/src/main/res/values/strings.xml

@@ -6,4 +6,6 @@
     <string name="action_settings">Settings</string>
     <string name="open_drawer">Open Drawer</string>
     <string name="close_drawer">Close Drawer</string>
+
+    <string name="retry">Retry</string>
 </resources>

bindingcollectionadapter-paging/build.gradle

@@ -32,7 +32,7 @@ android {
 
 dependencies {
     implementation project(':bindingcollectionadapter-recyclerview')
-    implementation 'androidx.paging:paging-runtime:2.0.0'
+    implementation 'androidx.paging:paging-runtime:3.0.0-beta03'
 
     testImplementation 'junit:junit:4.13.2'
     testImplementation 'org.assertj:assertj-core:3.6.2'