1166: Migration to Paging3 for MembersFragment

app/build.gradle.kts

@@ -53,7 +53,6 @@ configurations.all {
 
 dependencies {
     implementation(fileTree(mapOf("dir" to "libs", "include" to listOf("*.jar"))))
-    implementation(Dependencies.kotlin_stdlib)
     implementation(Dependencies.design)
     implementation(Dependencies.constraint_layout)
     implementation(Dependencies.appCompat)
@@ -78,4 +77,11 @@ dependencies {
 
     implementation(Dependencies.viewPager2)
     implementation(Dependencies.swipe_refresh_layout)
+
+    implementation(Dependencies.room_ktx)
+    implementation(Dependencies.room_runtime)
+    kapt(Dependencies.room_compiler)
+    implementation(Dependencies.room_paging)
+
+    implementation(Dependencies.paging3)
 }

app/src/main/AndroidManifest.xml

@@ -19,12 +19,10 @@
             android:theme="@style/AppTheme.NoActionBar" />
         <activity android:name=".view.activities.AboutActivity" />
         <activity android:name=".view.activities.FeedbackActivity" />
-        <activity
-            android:name=".view.activities.FilterActivity"
-            android:theme="@style/FilterTheme" />
         <activity
             android:name=".view.activities.SplashScreenActivity"
-            android:theme="@style/AppTheme.NoActionBar">
+            android:theme="@style/AppTheme.NoActionBar"
+            android:exported="true">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
 

app/src/main/java/org/anitab/mentorship/Injection.kt

@@ -0,0 +1,20 @@
+package org.anitab.mentorship
+
+import org.anitab.mentorship.local.UserDatabase
+/**
+ * Class that handles object creation.
+ * Like this, objects can be passed as parameters in the constructors and then replaced for
+ * testing, where needed.
+ */
+object Injection {
+
+    /**
+     * Provides context of [MentorshipApplication]
+     */
+    private fun provideApplicationContext() = MentorshipApplication.getContext()
+
+    /**
+     * Provides an instance of [UserDatabase]
+     */
+    fun provideUserDatabase(): UserDatabase = UserDatabase.getInstance(provideApplicationContext())
+}

app/src/main/java/org/anitab/mentorship/local/RemoteKeysDao.kt

@@ -0,0 +1,22 @@
+package org.anitab.mentorship.local
+
+import androidx.room.Dao
+import androidx.room.Insert
+import androidx.room.OnConflictStrategy
+import androidx.room.Query
+
+@Dao
+interface RemoteKeysDao {
+
+    @Insert(onConflict = OnConflictStrategy.REPLACE)
+    suspend fun insertAll(remoteKey: List<RemoteKeysEntity>)
+
+    @Query("SELECT * FROM remote_keys")
+    suspend fun getRemoteKeys(): List<RemoteKeysEntity>
+
+    @Query("SELECT * FROM remote_keys WHERE userId = :userId")
+    suspend fun remoteKeysRepoId(userId: Int): RemoteKeysEntity?
+
+    @Query("DELETE FROM remote_keys")
+    suspend fun clearRemoteKeys()
+}

app/src/main/java/org/anitab/mentorship/local/RemoteKeysEntity.kt

@@ -0,0 +1,14 @@
+package org.anitab.mentorship.local
+
+import android.os.Parcelable
+import androidx.room.Entity
+import androidx.room.PrimaryKey
+import kotlinx.android.parcel.Parcelize
+
+@Entity(tableName = "remote_keys")
+@Parcelize
+data class RemoteKeysEntity(
+    @PrimaryKey val userId: Int?,
+    val prevKey: Int?,
+    val nextKey: Int?
+) : Parcelable

app/src/main/java/org/anitab/mentorship/local/UserDao.kt

@@ -0,0 +1,21 @@
+package org.anitab.mentorship.local
+
+import androidx.paging.PagingSource
+import androidx.room.Dao
+import androidx.room.Insert
+import androidx.room.OnConflictStrategy
+import androidx.room.Query
+import org.anitab.mentorship.models.User
+
+@Dao
+interface UserDao {
+
+    @Insert(onConflict = OnConflictStrategy.REPLACE)
+    suspend fun insertUsers(users: List<User>)
+
+    @Query("SELECT * from user_table")
+    fun getAllUsers(): PagingSource<Int, User>
+
+    @Query("DELETE from user_table")
+    suspend fun clearAllUsers()
+}

app/src/main/java/org/anitab/mentorship/local/UserDatabase.kt

@@ -0,0 +1,38 @@
+package org.anitab.mentorship.local
+
+import android.content.Context
+import androidx.room.Database
+import androidx.room.Room
+import androidx.room.RoomDatabase
+import org.anitab.mentorship.models.User
+
+@Database(
+    entities = [User::class, RemoteKeysEntity::class],
+    version = 2,
+    exportSchema = false
+)
+abstract class UserDatabase : RoomDatabase() {
+
+    abstract fun userDao(): UserDao
+    abstract fun remoteKeyDao(): RemoteKeysDao
+
+    companion object {
+
+        @Volatile
+        private var INSTANCE: UserDatabase? = null
+
+        fun getInstance(context: Context): UserDatabase =
+            INSTANCE ?: synchronized(this) {
+                INSTANCE
+                    ?: buildDatabase(context).also { INSTANCE = it }
+            }
+
+        private fun buildDatabase(context: Context) =
+            Room.databaseBuilder(
+                context,
+                UserDatabase::class.java, "User.db"
+            )
+                .fallbackToDestructiveMigration()
+                .build()
+    }
+}

app/src/main/java/org/anitab/mentorship/models/User.kt

@@ -1,6 +1,9 @@
 package org.anitab.mentorship.models
 
 import android.os.Parcelable
+import androidx.room.Entity
+import androidx.room.PrimaryKey
+import com.google.gson.annotations.SerializedName
 import kotlinx.android.parcel.Parcelize
 
 /**
@@ -20,19 +23,21 @@ import kotlinx.android.parcel.Parcelize
  * @param availableToMentor true, if user is available to mentor, false if otherwise
  * @param slackUsername Slack username
  */
+
+@Entity(tableName = "user_table")
 @Parcelize
 data class User(
-    var id: Int? = null,
-    var username: String? = null,
-    var name: String? = null,
-    var email: String? = null,
-    var bio: String? = null,
-    var location: String? = null,
-    var occupation: String? = null,
-    var organization: String? = null,
-    var interests: String? = null,
-    var skills: String? = null,
-    var needMentoring: Boolean? = null,
-    var availableToMentor: Boolean? = null,
-    var slackUsername: String? = null
+    @PrimaryKey @field:SerializedName("id") var id: Int,
+    @field:SerializedName("username") var username: String? = null,
+    @field:SerializedName("name") var name: String? = null,
+    @field:SerializedName("email") var email: String? = null,
+    @field:SerializedName("bio") var bio: String? = null,
+    @field:SerializedName("location") var location: String? = null,
+    @field:SerializedName("occupation") var occupation: String? = null,
+    @field:SerializedName("organization") var organization: String? = null,
+    @field:SerializedName("interests") var interests: String? = null,
+    @field:SerializedName("skills") var skills: String? = null,
+    @field:SerializedName("need_mentoring") var needMentoring: Boolean? = null,
+    @field:SerializedName("available_to_mentor") var availableToMentor: Boolean? = null,
+    @field:SerializedName("slack_username") var slackUsername: String? = null
 ) : Parcelable

app/src/main/java/org/anitab/mentorship/remote/datamanager/UserDataManager.kt

@@ -1,38 +1,117 @@
 package org.anitab.mentorship.remote.datamanager
 
+import androidx.lifecycle.LiveData
+import androidx.lifecycle.map
+import androidx.paging.ExperimentalPagingApi
+import androidx.paging.Pager
+import androidx.paging.PagingConfig
+import androidx.paging.PagingData
+import androidx.paging.filter
+import androidx.paging.liveData
 import kotlinx.coroutines.CoroutineDispatcher
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.withContext
+import org.anitab.mentorship.Injection
 import org.anitab.mentorship.models.HomeStatistics
 import org.anitab.mentorship.models.User
 import org.anitab.mentorship.remote.ApiManager
 import org.anitab.mentorship.remote.requests.ChangePassword
-import org.anitab.mentorship.remote.requests.PaginationRequest
 import org.anitab.mentorship.remote.responses.CustomResponse
+import org.anitab.mentorship.utils.Constants.ITEMS_PER_PAGE
 
 /**
  * This class represents the data manager related to Users API
  */
 class UserDataManager(private val dispatcher: CoroutineDispatcher = Dispatchers.IO) {
 
     private val apiManager = ApiManager.instance
+    private val userDatabase = Injection.provideUserDatabase()
+
+    /** Paging 3 user data management starts **/
 
     /**
-     * This will call the getVerifiedUsers method of UserService interface
-     * @return an Observable of a list of [User]
+     * This will call the getAllUsers() method from UserDao interface
+     * @return stream of [User] list as PagingData with the help of [UserRemoteMediator]
+     * which manages making network call and storing user list in room db.
      */
-    suspend fun getUsers(): List<User> {
-        return withContext(dispatcher) { apiManager.userService.getVerifiedUsers() }
+
+    @OptIn(ExperimentalPagingApi::class)
+    fun getAllUsers(): LiveData<PagingData<User>> {
+        val pagingSourceFactory = { userDatabase.userDao().getAllUsers() }
+
+        return Pager(
+            config = PagingConfig(
+                pageSize = ITEMS_PER_PAGE,
+                enablePlaceholders = false
+            ),
+            remoteMediator = UserRemoteMediator(apiManager.userService, userDatabase),
+            pagingSourceFactory = pagingSourceFactory
+        ).liveData
     }
 
     /**
-     * This will call the getVerifiedUsers(pagination) method of UserService interface
-     * @return an Observable of a list of [User]
+     * This will call the getUsersWhoAreAvailableToMentor() method from UserDao interface
+     * @return stream of [User] list, who are available to be mentored as PagingData with
+     * the help of [UserRemoteMediator] which manages making network call and storing user
+     * list in room db.
      */
-    suspend fun getUsers(paginationRequest: PaginationRequest): List<User> {
-        return withContext(dispatcher) { apiManager.userService.getVerifiedUsers(paginationRequest.pagination) }
+    @OptIn(ExperimentalPagingApi::class)
+    fun getUsersWhoAreAvailableToMentor(): LiveData<PagingData<User>> {
+        val pagingSourceFactory = { userDatabase.userDao().getAllUsers() }
+
+        return Pager(
+            config = PagingConfig(
+                pageSize = ITEMS_PER_PAGE,
+                enablePlaceholders = false
+            ),
+            remoteMediator = UserRemoteMediator(apiManager.userService, userDatabase),
+            pagingSourceFactory = pagingSourceFactory
+        ).liveData
+            .map { pagingData -> pagingData.filter { user -> user.availableToMentor != null && user.availableToMentor == true } }
     }
 
+    /**
+     * This will call the getUsersWhoAreNeedMentoring() method from UserDao interface
+     * @return stream of [User] list, who are need mentoring as PagingData with the help of
+     * [UserRemoteMediator] which manages making network call and storing user list in room db.
+     */
+    @OptIn(ExperimentalPagingApi::class)
+    fun getUsersWhoAreNeedMentoring(): LiveData<PagingData<User>> {
+        val pagingSourceFactory = { userDatabase.userDao().getAllUsers() }
+
+        return Pager(
+            config = PagingConfig(
+                pageSize = ITEMS_PER_PAGE,
+                enablePlaceholders = false
+            ),
+            remoteMediator = UserRemoteMediator(apiManager.userService, userDatabase),
+            pagingSourceFactory = pagingSourceFactory
+        ).liveData
+            .map { pagingData -> pagingData.filter { user -> user.needMentoring != null && user.needMentoring == true } }
+    }
+
+    /**
+     * This will call the getUserWhoHaveSkills() method from UserDao interface
+     * @return stream of [User] list, who have at least 1 skill as PagingData with the help of
+     * [UserRemoteMediator] which manages making network call and storing user list in room db.
+     */
+    @OptIn(ExperimentalPagingApi::class)
+    fun getUserWhoHaveSkills(): LiveData<PagingData<User>> {
+        val pagingSourceFactory = { userDatabase.userDao().getAllUsers() }
+
+        return Pager(
+            config = PagingConfig(
+                pageSize = ITEMS_PER_PAGE,
+                enablePlaceholders = false
+            ),
+            remoteMediator = UserRemoteMediator(apiManager.userService, userDatabase),
+            pagingSourceFactory = pagingSourceFactory
+        ).liveData
+            .map { pagingData -> pagingData.filter { user -> user.skills != null } }
+    }
+
+    /** Paging 3 user data management end **/
+
     /**
      * This will call the getUser method of UserService interface
      * @return an Observable of [User]