Having the list backed by network only

app/src/main/java/com/example/android/codelabs/paging/Injection.kt

@@ -20,10 +20,7 @@ import android.content.Context
 import androidx.lifecycle.ViewModelProvider
 import com.example.android.codelabs.paging.api.GithubService
 import com.example.android.codelabs.paging.data.GithubRepository
-import com.example.android.codelabs.paging.db.GithubLocalCache
-import com.example.android.codelabs.paging.db.RepoDatabase
 import com.example.android.codelabs.paging.ui.ViewModelFactory
-import java.util.concurrent.Executors
 
 /**
  * Class that handles object creation.
@@ -32,27 +29,19 @@ import java.util.concurrent.Executors
  */
 object Injection {
 
-    /**
-     * Creates an instance of [GithubLocalCache] based on the database DAO.
-     */
-    private fun provideCache(context: Context): GithubLocalCache {
-        val database = RepoDatabase.getInstance(context)
-        return GithubLocalCache(database.reposDao(), Executors.newSingleThreadExecutor())
-    }
-
     /**
      * Creates an instance of [GithubRepository] based on the [GithubService] and a
      * [GithubLocalCache]
      */
-    private fun provideGithubRepository(context: Context): GithubRepository {
-        return GithubRepository(GithubService.create(), provideCache(context))
+    private fun provideGithubRepository(): GithubRepository {
+        return GithubRepository(GithubService.create())
     }
 
     /**
      * Provides the [ViewModelProvider.Factory] that is then used to get a reference to
      * [ViewModel] objects.
      */
-    fun provideViewModelFactory(context: Context): ViewModelProvider.Factory {
-        return ViewModelFactory(provideGithubRepository(context))
+    fun provideViewModelFactory(): ViewModelProvider.Factory {
+        return ViewModelFactory(provideGithubRepository())
     }
 }

app/src/main/java/com/example/android/codelabs/paging/data/GithubRepository.kt

@@ -17,19 +17,21 @@
 package com.example.android.codelabs.paging.data
 
 import android.util.Log
+import androidx.lifecycle.LiveData
 import androidx.lifecycle.MutableLiveData
+import androidx.lifecycle.Transformations
 import com.example.android.codelabs.paging.api.GithubService
 import com.example.android.codelabs.paging.api.searchRepos
-import com.example.android.codelabs.paging.db.GithubLocalCache
+import com.example.android.codelabs.paging.model.Repo
 import com.example.android.codelabs.paging.model.RepoSearchResult
 
 /**
  * Repository class that works with local and remote data sources.
  */
-class GithubRepository(
-    private val service: GithubService,
-    private val cache: GithubLocalCache
-) {
+class GithubRepository(private val service: GithubService) {
+
+    // keep the list of responses
+    private val inMemoryCache = MutableLiveData<List<Repo>>()
 
     // keep the last requested page. When the request is successful, increment the page number.
     private var lastRequestedPage = 1
@@ -48,8 +50,8 @@ class GithubRepository(
         lastRequestedPage = 1
         requestAndSaveData(query)
 
-        // Get data from the local cache
-        val data = cache.reposByName(query)
+        // Get data from the in memory cache
+        val data = reposByName(query)
 
         return RepoSearchResult(data, networkErrors)
     }
@@ -63,16 +65,33 @@ class GithubRepository(
 
         isRequestInProgress = true
         searchRepos(service, query, lastRequestedPage, NETWORK_PAGE_SIZE, { repos ->
-            cache.insert(repos) {
-                lastRequestedPage++
-                isRequestInProgress = false
-            }
+            // add the new result list to the existing list
+            val allResults = mutableListOf<Repo>()
+            inMemoryCache.value?.let { allResults.addAll(it) }
+            allResults.addAll(repos)
+
+            inMemoryCache.postValue(allResults)
+            lastRequestedPage++
+            isRequestInProgress = false
         }, { error ->
             networkErrors.postValue(error)
             isRequestInProgress = false
         })
     }
 
+    private fun reposByName(query: String): LiveData<List<Repo>> {
+        return Transformations.switchMap(inMemoryCache) { repos ->
+            // from the in memory cache select only the repos whose name or description matches
+            // the query. Then order the results.
+            val filteredList = repos.filter {
+                it.name.contains(query, true) ||
+                        (it.description != null && it.description.contains(query, true))
+            }.sortedWith(compareByDescending<Repo> { it.stars }.thenBy { it.name })
+
+            MutableLiveData(filteredList)
+        }
+    }
+
     companion object {
         private const val NETWORK_PAGE_SIZE = 50
     }

app/src/main/java/com/example/android/codelabs/paging/model/Repo.kt

@@ -36,4 +36,9 @@ data class Repo(
     @field:SerializedName("stargazers_count") val stars: Int,
     @field:SerializedName("forks_count") val forks: Int,
     @field:SerializedName("language") val language: String?
-)
+){
+
+    override fun toString(): String {
+        return "Repo(name='$name', stars=$stars)"
+    }
+}

app/src/main/java/com/example/android/codelabs/paging/ui/SearchRepositoriesActivity.kt

@@ -24,7 +24,7 @@ import android.view.inputmethod.EditorInfo
 import android.widget.Toast
 import androidx.appcompat.app.AppCompatActivity
 import androidx.lifecycle.Observer
-import androidx.lifecycle.ViewModelProviders
+import androidx.lifecycle.ViewModelProvider
 import androidx.recyclerview.widget.DividerItemDecoration
 import com.example.android.codelabs.paging.Injection
 import com.example.android.codelabs.paging.R
@@ -41,7 +41,7 @@ class SearchRepositoriesActivity : AppCompatActivity() {
         setContentView(R.layout.activity_search_repositories)
 
         // get the view model
-        viewModel = ViewModelProviders.of(this, Injection.provideViewModelFactory(this))
+        viewModel = ViewModelProvider(this, Injection.provideViewModelFactory())
                 .get(SearchRepositoriesViewModel::class.java)
 
         // add dividers between RecyclerView's row items