Use Flow instead of LiveData in the Test App (readium#461)

Author: stevenzeck

test-app/src/main/java/org/readium/r2/testapp/bookshelf/BookshelfFragment.kt

@@ -19,8 +19,13 @@ import androidx.activity.result.ActivityResultLauncher
 import androidx.activity.result.contract.ActivityResultContracts
 import androidx.fragment.app.Fragment
 import androidx.fragment.app.activityViewModels
+import androidx.lifecycle.Lifecycle
+import androidx.lifecycle.lifecycleScope
+import androidx.lifecycle.repeatOnLifecycle
 import androidx.recyclerview.widget.RecyclerView
 import com.google.android.material.dialog.MaterialAlertDialogBuilder
+import kotlinx.coroutines.flow.collectLatest
+import kotlinx.coroutines.launch
 import org.readium.r2.shared.util.AbsoluteUrl
 import org.readium.r2.testapp.Application
 import org.readium.r2.testapp.R
@@ -103,9 +108,12 @@ class BookshelfFragment : Fragment() {
                 )
             )
         }
-
-        bookshelfViewModel.books.observe(viewLifecycleOwner) {
-            bookshelfAdapter.submitList(it)
+        lifecycleScope.launch {
+            repeatOnLifecycle(Lifecycle.State.STARTED) {
+                bookshelfViewModel.books.collectLatest {
+                    bookshelfAdapter.submitList(it)
+                }
+            }
         }
 
         binding.bookshelfAddBookFab.setOnClickListener {

test-app/src/main/java/org/readium/r2/testapp/catalogs/CatalogFeedListFragment.kt

@@ -18,10 +18,15 @@ import android.widget.EditText
 import androidx.appcompat.app.AlertDialog
 import androidx.fragment.app.Fragment
 import androidx.fragment.app.viewModels
+import androidx.lifecycle.Lifecycle
+import androidx.lifecycle.lifecycleScope
+import androidx.lifecycle.repeatOnLifecycle
 import androidx.recyclerview.widget.LinearLayoutManager
 import androidx.recyclerview.widget.RecyclerView
 import com.google.android.material.dialog.MaterialAlertDialogBuilder
 import com.google.android.material.snackbar.Snackbar
+import kotlinx.coroutines.flow.collectLatest
+import kotlinx.coroutines.launch
 import org.readium.r2.testapp.R
 import org.readium.r2.testapp.data.model.Catalog
 import org.readium.r2.testapp.databinding.FragmentCatalogFeedListBinding
@@ -62,9 +67,13 @@ class CatalogFeedListFragment : Fragment() {
             )
         }
 
-        catalogFeedListViewModel.catalogs.observe(viewLifecycleOwner, {
-            catalogsAdapter.submitList(it)
-        })
+        lifecycleScope.launch {
+            viewLifecycleOwner.repeatOnLifecycle(Lifecycle.State.STARTED) {
+                catalogFeedListViewModel.catalogs.collectLatest {
+                    catalogsAdapter.submitList(it)
+                }
+            }
+        }
 
         val version = 2
         val VERSION_KEY = "OPDS_CATALOG_VERSION"

test-app/src/main/java/org/readium/r2/testapp/data/BookRepository.kt

@@ -7,7 +7,6 @@
 package org.readium.r2.testapp.data
 
 import androidx.annotation.ColorInt
-import androidx.lifecycle.LiveData
 import java.io.File
 import kotlinx.coroutines.flow.Flow
 import org.joda.time.DateTime
@@ -25,7 +24,7 @@ import org.readium.r2.testapp.utils.extensions.readium.authorName
 class BookRepository(
     private val booksDao: BooksDao
 ) {
-    fun books(): LiveData<List<Book>> = booksDao.getAllBooks()
+    fun books(): Flow<List<Book>> = booksDao.getAllBooks()
 
     suspend fun get(id: Long) = booksDao.get(id)
 
@@ -48,7 +47,7 @@ class BookRepository(
         return booksDao.insertBookmark(bookmark)
     }
 
-    fun bookmarksForBook(bookId: Long): LiveData<List<Bookmark>> =
+    fun bookmarksForBook(bookId: Long): Flow<List<Bookmark>> =
         booksDao.getBookmarksForBook(bookId)
 
     suspend fun deleteBookmark(bookmarkId: Long) = booksDao.deleteBookmark(bookmarkId)

test-app/src/main/java/org/readium/r2/testapp/data/CatalogRepository.kt

@@ -6,7 +6,7 @@
 
 package org.readium.r2.testapp.data
 
-import androidx.lifecycle.LiveData
+import kotlinx.coroutines.flow.Flow
 import org.readium.r2.testapp.data.db.CatalogDao
 import org.readium.r2.testapp.data.model.Catalog
 
@@ -16,7 +16,7 @@ class CatalogRepository(private val catalogDao: CatalogDao) {
         return catalogDao.insertCatalog(catalog)
     }
 
-    fun getCatalogsFromDatabase(): LiveData<List<Catalog>> = catalogDao.getCatalogModels()
+    fun getCatalogsFromDatabase(): Flow<List<Catalog>> = catalogDao.getCatalogModels()
 
     suspend fun deleteCatalog(id: Long) = catalogDao.deleteCatalog(id)
 }

test-app/src/main/java/org/readium/r2/testapp/data/db/BooksDao.kt

@@ -7,7 +7,6 @@
 package org.readium.r2.testapp.data.db
 
 import androidx.annotation.ColorInt
-import androidx.lifecycle.LiveData
 import androidx.room.Dao
 import androidx.room.Insert
 import androidx.room.OnConflictStrategy
@@ -43,18 +42,18 @@ interface BooksDao {
 
     /**
      * Retrieve all books
-     * @return List of books as LiveData
+     * @return List of books as Flow
      */
     @Query("SELECT * FROM " + Book.TABLE_NAME + " ORDER BY " + Book.CREATION_DATE + " desc")
-    fun getAllBooks(): LiveData<List<Book>>
+    fun getAllBooks(): Flow<List<Book>>
 
     /**
      * Retrieve all bookmarks for a specific book
      * @param bookId The ID of the book
-     * @return List of bookmarks for the book as LiveData
+     * @return List of bookmarks for the book as Flow
      */
     @Query("SELECT * FROM " + Bookmark.TABLE_NAME + " WHERE " + Bookmark.BOOK_ID + " = :bookId")
-    fun getBookmarksForBook(bookId: Long): LiveData<List<Bookmark>>
+    fun getBookmarksForBook(bookId: Long): Flow<List<Bookmark>>
 
     /**
      * Retrieve all highlights for a specific book

test-app/src/main/java/org/readium/r2/testapp/data/db/CatalogDao.kt

@@ -6,11 +6,11 @@
 
 package org.readium.r2.testapp.data.db
 
-import androidx.lifecycle.LiveData
 import androidx.room.Dao
 import androidx.room.Insert
 import androidx.room.OnConflictStrategy
 import androidx.room.Query
+import kotlinx.coroutines.flow.Flow
 import org.readium.r2.testapp.data.model.Catalog
 
 @Dao
@@ -26,19 +26,19 @@ interface CatalogDao {
 
     /**
      * Retrieve list of Catalog models based on Catalog model
-     * @return List of Catalog models as LiveData
+     * @return List of Catalog models as Flow
      */
     @Query(
         "SELECT * FROM " + Catalog.TABLE_NAME + " WHERE " + Catalog.TITLE + " = :title AND " + Catalog.HREF + " = :href AND " + Catalog.TYPE + " = :type"
     )
-    fun getCatalogModels(title: String, href: String, type: Int): LiveData<List<Catalog>>
+    fun getCatalogModels(title: String, href: String, type: Int): Flow<List<Catalog>>
 
     /**
      * Retrieve list of all Catalog models
-     * @return List of Catalog models as LiveData
+     * @return List of Catalog models as Flow
      */
     @Query("SELECT * FROM " + Catalog.TABLE_NAME)
-    fun getCatalogModels(): LiveData<List<Catalog>>
+    fun getCatalogModels(): Flow<List<Catalog>>
 
     /**
      * Deletes an Catalog model

test-app/src/main/java/org/readium/r2/testapp/outline/BookmarksFragment.kt

@@ -13,12 +13,17 @@ import android.view.ViewGroup
 import androidx.appcompat.widget.PopupMenu
 import androidx.fragment.app.Fragment
 import androidx.fragment.app.setFragmentResult
+import androidx.lifecycle.Lifecycle
 import androidx.lifecycle.ViewModelProvider
+import androidx.lifecycle.lifecycleScope
+import androidx.lifecycle.repeatOnLifecycle
 import androidx.recyclerview.widget.DiffUtil
 import androidx.recyclerview.widget.LinearLayoutManager
 import androidx.recyclerview.widget.ListAdapter
 import androidx.recyclerview.widget.RecyclerView
 import kotlin.math.roundToInt
+import kotlinx.coroutines.flow.collectLatest
+import kotlinx.coroutines.launch
 import org.joda.time.DateTime
 import org.joda.time.format.DateTimeFormat
 import org.readium.r2.shared.publication.Publication
@@ -73,9 +78,13 @@ class BookmarksFragment : Fragment() {
             { it.resourceIndex },
             { it.locator.locations.progression }
         )
-        viewModel.getBookmarks().observe(viewLifecycleOwner) {
-            val bookmarks = it.sortedWith(comparator)
-            bookmarkAdapter.submitList(bookmarks)
+        lifecycleScope.launch {
+            viewLifecycleOwner.repeatOnLifecycle(Lifecycle.State.STARTED) {
+                viewModel.getBookmarks().collectLatest {
+                    val bookmarks = it.sortedWith(comparator)
+                    bookmarkAdapter.submitList(bookmarks)
+                }
+            }
         }
     }