Add paging for Item List

app/build.gradle

@@ -54,18 +54,19 @@ android {
 
 dependencies {
     def lifecycle_version = "2.3.1"
+    def paging_version = "3.0.0"
 
     implementation 'androidx.preference:preference-ktx:1.1.1'
 
     implementation fileTree(dir: 'libs', include: ['*.jar'])
-    implementation 'org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.5.0'
+    implementation 'org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.5.10'
     implementation 'androidx.appcompat:appcompat:1.3.0'
     implementation 'androidx.constraintlayout:constraintlayout:2.0.4'
     implementation 'com.google.android.material:material:1.3.0'
 
     // Android KTX
     implementation "androidx.core:core-ktx:1.5.0"
-    debugImplementation "androidx.fragment:fragment-testing:1.3.1"
+    debugImplementation "androidx.fragment:fragment-testing:1.3.4"
 
     // Timber
     implementation 'com.jakewharton.timber:timber:4.7.1'
@@ -88,11 +89,9 @@ dependencies {
     androidTestImplementation 'com.google.dagger:hilt-android-testing:2.35.1'
     // Make Hilt generate code in the androidTest folder
     kaptAndroidTest 'com.google.dagger:hilt-android-compiler:2.35.1'
-
     // For instrumentation tests
     androidTestImplementation 'com.google.dagger:hilt-android-testing:2.35.1'
     kaptAndroidTest 'com.google.dagger:hilt-android-compiler:2.35.1'
-
     // For local unit tests
     testImplementation 'com.google.dagger:hilt-android-testing:2.35.1'
     kaptTest 'com.google.dagger:hilt-android-compiler:2.35.1'
@@ -118,14 +117,21 @@ dependencies {
     implementation "androidx.navigation:navigation-fragment-ktx:$nav_version"
     implementation "androidx.navigation:navigation-ui-ktx:$nav_version"
 
+    // Paging
+    implementation "androidx.paging:paging-runtime-ktx:$paging_version"
+    // alternatively - without Android dependencies for tests
+    testImplementation "androidx.paging:paging-common-ktx:$paging_version"
+    // optional - Jetpack Compose integration
+    implementation "androidx.paging:paging-compose:1.0.0-alpha09"
+
     // Feature module Support
     implementation "androidx.navigation:navigation-dynamic-features-fragment:$nav_version"
 
     // Testing Navigation
     androidTestImplementation "androidx.navigation:navigation-testing:$nav_version"
 
     // Jetpack Compose Integration
-    implementation "androidx.navigation:navigation-compose:1.0.0-alpha09"
+    implementation "androidx.navigation:navigation-compose:2.4.0-alpha01"
 
 //    Color Picker Library
     implementation 'com.jaredrummler:colorpicker:1.1.0'

app/src/main/java/com/fazemeright/myinventorytracker/domain/database/offline/room/dao/InventoryItemDao.kt

@@ -1,6 +1,7 @@
 package com.fazemeright.myinventorytracker.domain.database.offline.room.dao
 
 import androidx.lifecycle.LiveData
+import androidx.paging.PagingSource
 import androidx.room.Dao
 import androidx.room.Query
 import androidx.room.Transaction
@@ -41,13 +42,13 @@ interface InventoryItemDao : BaseDao<InventoryItem> {
 
     @Transaction
     @Query("SELECT * FROM my_inventory_table")
-    fun getItemsWithBagLive(): LiveData<List<ItemWithBag>>
+    fun getItemsWithBagLive(): PagingSource<Int, ItemWithBag>/*LiveData<List<ItemWithBag>>*/
 
     @Transaction
     @Query("SELECT * FROM my_inventory_table")
     fun getItemsWithBag(): List<ItemWithBag>
 
     @Transaction
     @Query("SELECT * FROM my_inventory_table WHERE itemName LIKE '%' || :searchString || '%' ORDER BY itemName")
-    fun searchItems(searchString: String): List<ItemWithBag>
+    fun searchItems(searchString: String): PagingSource<Int, ItemWithBag>
 }

app/src/main/java/com/fazemeright/myinventorytracker/repository/InventoryRepository.kt

@@ -1,6 +1,10 @@
 package com.fazemeright.myinventorytracker.repository
 
 import androidx.lifecycle.LiveData
+import androidx.paging.Pager
+import androidx.paging.PagingConfig
+import androidx.paging.PagingData
+import androidx.paging.liveData
 import com.fazemeright.myinventorytracker.domain.authentication.UserAuthentication
 import com.fazemeright.myinventorytracker.domain.authentication.firebase.FireBaseUserAuthentication
 import com.fazemeright.myinventorytracker.domain.database.offline.room.dao.BagItemDao
@@ -110,14 +114,18 @@ class InventoryRepository @Inject constructor(
         }
     }
 
-    override fun getItemsWithBagLive(): LiveData<List<ItemWithBag>> {
-        return inventoryItemDao.getItemsWithBagLive()
+    override fun getItemsWithBagLive(): LiveData<PagingData<ItemWithBag>> {
+        return Pager(
+            config = pagingConfig,
+            pagingSourceFactory = { inventoryItemDao.getItemsWithBagLive() }
+        ).liveData
     }
 
-    override suspend fun searchInventoryItems(searchText: String): List<ItemWithBag> {
-        return withContext(Dispatchers.IO) {
-            inventoryItemDao.searchItems(searchText)
-        }
+    override fun searchInventoryItems(searchText: String): LiveData<PagingData<ItemWithBag>> {
+        return Pager(
+            config = pagingConfig,
+            pagingSourceFactory = { inventoryItemDao.searchItems(searchText) }
+        ).liveData
     }
 
     override suspend fun getInventoryItemById(itemId: Int): InventoryItem? {
@@ -201,4 +209,13 @@ class InventoryRepository @Inject constructor(
         }
 //        TODO: Clear Shared Preferences
     }
+
+    companion object {
+        val pagingConfig = PagingConfig(
+            pageSize = 20,
+            prefetchDistance = 10,
+            enablePlaceholders = false,
+            initialLoadSize = 20
+        )
+    }
 }

app/src/main/java/com/fazemeright/myinventorytracker/repository/Repository.kt

@@ -1,6 +1,8 @@
 package com.fazemeright.myinventorytracker.repository
 
 import androidx.lifecycle.LiveData
+import androidx.paging.PagedList
+import androidx.paging.PagingData
 import com.fazemeright.myinventorytracker.domain.models.BagItem
 import com.fazemeright.myinventorytracker.domain.models.InventoryItem
 import com.fazemeright.myinventorytracker.domain.models.ItemWithBag
@@ -66,12 +68,12 @@ interface Repository {
     /**
      * Get items with bag data through livedata
      */
-    fun getItemsWithBagLive(): LiveData<List<ItemWithBag>>
+    fun getItemsWithBagLive(): LiveData<PagingData<ItemWithBag>>
 
     /**
      * Search for inventory items with given search string
      */
-    suspend fun searchInventoryItems(searchText: String): List<ItemWithBag>
+    fun searchInventoryItems(searchText: String): LiveData<PagingData<ItemWithBag>>
 
     /**
      * Get inventory item with given id

app/src/main/java/com/fazemeright/myinventorytracker/ui/itemlist/ItemListAdapter.kt

@@ -2,26 +2,26 @@ package com.fazemeright.myinventorytracker.ui.itemlist
 
 import android.view.LayoutInflater
 import android.view.ViewGroup
+import androidx.paging.PagingDataAdapter
 import androidx.recyclerview.widget.DiffUtil
-import androidx.recyclerview.widget.ListAdapter
 import androidx.recyclerview.widget.RecyclerView
 import com.fazemeright.myinventorytracker.databinding.ListInventoryItemBinding
 import com.fazemeright.myinventorytracker.domain.models.ItemWithBag
 
 class ItemListAdapter(private val clickListener: ItemListener) :
-    ListAdapter<ItemWithBag,
-        ItemListAdapter.ViewHolder>(ItemListDiffCallback()) {
+    PagingDataAdapter<ItemWithBag,
+            ItemListAdapter.ViewHolder>(ItemListDiffCallback()) {
 
     override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
         return ViewHolder.from(parent)
     }
 
-    fun updateList(list: List<ItemWithBag>?) {
+    /*fun updateList(list: List<ItemWithBag>?) {
         submitList(list)
-    }
+    }*/
 
     override fun onBindViewHolder(holder: ViewHolder, position: Int) {
-        getItem(position).also {
+        getItem(position)?.let {
             holder.bind(it, clickListener)
         }
     }

app/src/main/java/com/fazemeright/myinventorytracker/ui/itemlist/ItemListFragment.kt

@@ -17,7 +17,9 @@ import com.fazemeright.myinventorytracker.ui.base.BaseFragment
 import com.fazemeright.myinventorytracker.ui.settings.SettingsActivity
 import com.google.android.material.snackbar.Snackbar
 import dagger.hilt.android.AndroidEntryPoint
-import timber.log.Timber
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.launch
 
 @AndroidEntryPoint
 class ItemListFragment : BaseFragment<FragmentItemListBinding>() {
@@ -51,9 +53,10 @@ class ItemListFragment : BaseFragment<FragmentItemListBinding>() {
             viewLifecycleOwner,
             {
                 it?.let {
-                    adapter.updateList(it)
+                    CoroutineScope(Dispatchers.IO).launch {
+                        adapter.submitData(it)
+                    }
                 }
-                Timber.i("received in onCreate: ${it.size}")
             }
         )
 

app/src/main/java/com/fazemeright/myinventorytracker/ui/itemlist/ItemListViewModel.kt

@@ -1,7 +1,11 @@
 package com.fazemeright.myinventorytracker.ui.itemlist
 
 import android.app.Application
-import androidx.lifecycle.*
+import androidx.lifecycle.LiveData
+import androidx.lifecycle.MutableLiveData
+import androidx.lifecycle.switchMap
+import androidx.lifecycle.viewModelScope
+import androidx.paging.PagingData
 import com.fazemeright.myinventorytracker.domain.models.InventoryItem
 import com.fazemeright.myinventorytracker.domain.models.ItemWithBag
 import com.fazemeright.myinventorytracker.repository.InventoryRepository
@@ -37,14 +41,11 @@ class ItemListViewModel @Inject constructor(
         _searchString.value = ""
     }
 
-    val items = _searchString.switchMap {
+    val items: LiveData<PagingData<ItemWithBag>> = _searchString.switchMap {
         if (it.isEmpty()) repository.getItemsWithBagLive()
-        else
-            liveData {
-                emit(
-                    repository.searchInventoryItems(it)
-                )
-            }
+        else {
+            repository.searchInventoryItems(it)
+        }
     }
 
     fun onSearchClicked(searchText: String) {