Room with Kotlin

LINE Developer Meetup #25

Transcript

1. Room with Kotlin LINE Developer Meetup #25 in Fukuoka
2. About Me Kazuki Nara Android Developer @ AWA Co., Ltd. http://github.com/kazukinr http://www.facebook.com/kazuki.nara
3. About Room - Android Architecture Components のひとつ - SQLiteDatabaseの薄いラッパー - Entity = テーブル定義（DDL） - Dao = SQL（クエリ・DML） - クエリの戻り型はPOJOで柔軟に定義可能 - Dao、Migrationのテストが書きやすい
4. build.gradle dependencies { .... implementation 'android.arch.persistence.room:runtime:1.0.0' implementation 'android.arch.persistence.room:rxjava2:1.0.0' annotationProcessor 'android.arch.persistence.room:compiler:1.0.0' testImplementation 'android.arch.core:core-testing:1.0.0' testImplementation 'android.arch.persistence.room:testing:1.0.0' .... }
5. build.gradle apply plugin: 'kotlin-android' apply plugin: 'kotlin-android-extensions' apply plugin: 'kotlin-kapt' dependencies { .... implementation 'android.arch.persistence.room:runtime:1.0.0' implementation 'android.arch.persistence.room:rxjava2:1.0.0' kapt 'android.arch.persistence.room:compiler:1.0.0' testImplementation 'android.arch.core:core-testing:1.0.0' testImplementation 'android.arch.persistence.room:testing:1.0.0' .... }
6. Entity @Entity public class User { @PrimaryKey private long id; private String name; public long getId() { return id; } public void setId(long id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } }
7. Entity @Entity data class User( @PrimaryKey var id: Long, var name: String )
8. Entity @Entity public class User { @PrimaryKey private long id; private String name; public long getId() { return id; } public void setId(long id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } } ≠ @Entity data class User( @PrimaryKey var id: Long, var name: String )
9. Entity @Entity public class User { @PrimaryKey private long id; private String name; public long getId() { return id; } public void setId(long id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } } CREATE TABLE User ( id INTEGER NOT NULL, name TEXT, PRIMARY KEY(id) ) →
10. Entity CREATE TABLE User ( id INTEGER NOT NULL, name TEXT NOT NULL, PRIMARY KEY(id) ) → @Entity data class User( @PrimaryKey var id: Long, var name: String )
11. Entity @Entity public class User { @PrimaryKey private long id; private String name; public long getId() { return id; } public void setId(long id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } } ＝ @Entity data class User( @PrimaryKey var id: Long, var name: String? )
12. Dao @Dao public interface UserDao { @Query("SELECT * FROM User") List<User> getAll(); @Query("SELECT * FROM User WHERE id = :id") User getById(String id); @Insert void insert(User user); @Update void update(User user); @Delete void delete(User user); @Query("UPDATE User SET name = :name WHERE id = :id") void updateNameById(long id, String name); }
13. Dao @Dao interface UserDao { @Query("SELECT * FROM User") fun getAll(): List<User> @Query("SELECT * FROM User WHERE id = :id") fun getById(id: String): User? @Insert fun insert(user: User) @Update fun update(user: User) @Delete fun delete(user: User) @Query("UPDATE User SET name = :name WHERE id = :id") fun updateNameById(id: Long, name: String) }
14. Dao with RxJava2 @Dao interface UserDao { @Query("SELECT * FROM User") fun getAll(): Flowable<List<User>> @Query("SELECT * FROM User WHERE id = :id") fun getById(id: String): Maybe<User> @Insert fun insert(user: User) @Update fun update(user: User) @Delete fun delete(user: User) @Query("UPDATE User SET name = :name WHERE id = :id") fun updateNameById(id: Long, name: String) }
15. Migration static final MIGRATION_1_2 = Migration(1, 2) { @Override public void migrate(SupportSQLiteDatabase db) { db.execSQL("CREATE TABLE User2 (" + " id INTEGER PRIMARY KEY NOT NULL," + " first_name TEXT NOT NULL" + " last_name TEXT NOT NULL" + ")"); Cursor cursor = db.query("SELECT * FROM User"); while (cursor.moveToNext()) { String name = cursor.getString(cursor.getColumnIndex("name")); ContentValues values = ContentValues(); values.put("id", cursor.getString(cursor.getColumnIndex("id"))); values.put("first_name", name.split(" ")[0]); values.put("last_name", name.split(" ")[1]); db.insert("User2", OnConflictStrategy.REPLACE, values); } cursor.close(); } }
16. Migration val migration_1_2 = object : Migration(1, 2) { override fun migrate(db: SupportSQLiteDatabase) { db.execSQL(""" CREATE TABLE User2 ( id INTEGER PRIMARY KEY NOT NULL, name TEXT NOT NULL, last_name TEXT NOT NULL ) """.trimIndent()) db.query("SELECT * FROM User").use { cursor -> while (cursor.moveToNext()) { val name = cursor.getString(cursor.getColumnIndex("name")) val values = ContentValues().apply { put("id", cursor.getString(cursor.getColumnIndex("id"))) put("first_name", name.split(" ")[0]) put("last_name", name.split(" ")[1]) } db.insert("User2", OnConflictStrategy.REPLACE, values) } } } }
17. Database @Database( version = 2, entities = {User.class}, exportSchema = false ) public abstract class MyDatabase extends RoomDatabase { public abstract UserDao userDao(); }
18. Database @Database( version = 2, entities = arrayOf(User::class), exportSchema = false ) abstract class MyDatabase : RoomDatabase() { abstract fun userDao(): UserDao }
19. Create RoomDatabase // must be Singleton. val database = Room.databaseBuilder(context, MyDatabase::class.java, "db-name") .addMigrations(migration_1_2) .build() // with Dagger. @Module class AppModule { @Provides fun provideApplicationContext(application: Application): Context { return application.applicationContext } @Singleton @Provides fun provideMyDatabase(context: Context): MyDatabase { return Room.databaseBuilder(context, MyDatabase::class.java, "db-name") .addMigrations(migration_1_2) .build() } }
20. Summary - Kotlinで記述することで全体的に簡潔に - テーブル定義、SQLは意識する必要あり - 特に意図しないNOT NULL制約に注意
21. Room Tips - トランザクション管理したい - UI Threadでアクセスしたい - コード<>DBの型変換を自動化したい - 関連Entityを同時に取得したい - 既存のSQLiteDatabaseにRoomを適用したい
22. トランザクション管理したい @Dao abstract class UserDao { @Insert abstract fun insert(user: User) @Delete abstract fun delete(user: User) @Transaction fun insertAndDelete(newItem: User, oldItem: User) { insert(newItem) delete(oldItem) } }
23. UI Threadでアクセスしたい val database = Room.databaseBuilder(context, MyDatabase::class.java, "db-name") .addMigrations(migration_1_2) .allowMainThreadQueries() .build()
24. コード<>DBの型変換を自動化したい class Converters { @TypeConverter fun fromTimestamp(value: Long?): Date? { return value?.let { Date(it) } } @TypeConverter fun dateToTimestamp(value: Date?): Long? { return date?.let { it.time } } } @Database( version = 2, entities = arrayOf(User::class), exportSchema = false ) @TypeConverters(Converters::class) abstract class MyDatabase : RoomDatabase() { // Daos. }
25. 関連Entityを同時に取得したい data class RoleAndUsers( var id: Long, var name: String ) { @Relation(parentColumn = "id", entityColumn = "roleId", entity = User::class) var users: List<User> } @Dao interface RoleDao { @Transaction @Query("SELECT * FROM Role") fun findAllWithUsers(): List<RoleAndUsers> }
26. 既存のSQLiteDatabaseにRoomを適用したい // In case existing SQLiteDatabase schema version is 2. @Database( version = 3, // version must be incremented. entities = arrayOf(User::class), exportSchema = false ) abstract class MyDatabase : RoomDatabase() { // Daos. } val migration_2_3 = object : Migration(2, 3) { override fun migrate(db: SupportSQLiteDatabase) { // no-op. // Room add room_master_table into your SQLiteDatabase automatically. } } val database = Room.databaseBuilder(context, MyDatabase::class.java, "db-name") .addMigrations(migration_1_2, migration_2_3) .build()
27. Conclusion Have a Nice Kotlin!