Android Jetpack: Room persistence library
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- Discuss the Android Jetpack: New Android libraries officially developed by Google. - Discuss the Room persistence library in Jetpack. How does Room library help developer life easier when working with databases.
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Android Jetpack: Room persistence library
- 2. When start new android app … - Database: - Native SQLite - ORM wrapper on SQLite: DBFlow - Different database engines: Realm.
- 3. When start new android app … - Running a jobs: - AlarmManager + Broadcast Receiver - Firebase JobDispatcher - JobScheduler - GCMNetworkManager -
- 5. When start new android app … - Control data Slow and update latest data on UI. - Loading data: - Loading data from network. - Loading data from on-device database. - Loading data from multiple sources.
- 9. ViewModel
- 10. Live Data
- 17. Room Components
- 18. Entity public class Word { private String mWord; public Word(String word) {this.mWord = word;} public String getWord(){return this.mWord;} }
- 19. Entity @Entity(tableName = "word_table") public class Word { @PrimaryKey @NonNull @ColumnInfo(name = "word") private String mWord; public Word(String word) {this.mWord = word;} public String getWord(){return this.mWord;} }
- 24. DAO @Dao public interface WordDao { @Insert void insert(Word word); @Query("DELETE FROM word_table") void deleteAll(); @Query("SELECT * from word_table ORDER BY word ASC") LiveData<List<Word>> getAllWords(); }
- 25. DAO -Use annotation for simple actions such as insert/delete/update @Dao public interface WordDao { @Insert void insert(Word word); }
- 26. DAO -Write custom query. @Dao public interface WordDao { @Query("DELETE FROM word_table") void deleteAll(); @Query("SELECT * from word_table ORDER BY word ASC") LiveData<List<Word>> getAllWords(); }
- 29. DAO -Return LiveData data. @Dao public interface WordDao { @Query("SELECT * from word_table ORDER BY word ASC") LiveData<List<Word>> getAllWords(); }
- 30. Room Database -Abstraction over SQLiteHelper. @Database(entities = {Word.class}, version = 1) public abstract class WordRoomDatabase extends RoomDatabase { public abstract WordDao wordDao(); private static volatile WordRoomDatabase INSTANCE; static WordRoomDatabase getDatabase(final Context context) { if (INSTANCE == null) { synchronized (WordRoomDatabase.class) { if (INSTANCE == null) { // Create database here INSTANCE = Room.databaseBuilder(context.getApplicationContext(), WordRoomDatabase.class, "word_database") .addCallback(sRoomDatabaseCallback) .build(); } } } return INSTANCE; } }
- 31. Room Database
- 34. WorkSlow
- 36. Step 1: Add dependencies dependencies { // Room components implementation "android.arch.persistence.room:runtime:$rootProject.roomVersion" annotationProcessor "android.arch.persistence.room:compiler:$rootProject.roomVersion" androidTestImplementation "android.arch.persistence.room:testing:$rootProject.roomVersion" // Lifecycle components implementation "android.arch.lifecycle:extensions:$rootProject.archLifecycleVersion" annotationProcessor "android.arch.lifecycle:compiler:$rootProject.archLifecycleVersion" } build.gradle (module app)
- 37. Step 2: Update model to entity @Entity(tableName = "word_table") public class Word { @PrimaryKey @NonNull @ColumnInfo(name = "word") private String mWord; public Word(String word) {this.mWord = word;} public String getWord(){return this.mWord;} }
- 38. Step 3: Create DAO @Dao public interface WordDao { @Insert void insert(Word word); }
- 39. Step 3: Create DAO @Dao public interface WordDao { @Insert void insert(Word word); @Query("DELETE FROM word_table") void deleteAll(); @Query("SELECT * from word_table ORDER BY word ASC") LiveData<List<Word>> getAllWords(); }
- 40. Step 4: Create Database @Database(entities = {Word.class}, version = 1) public abstract class WordRoomDatabase extends RoomDatabase { }
- 41. Step 4: Create Database @Database(entities = {Word.class}, version = 1) public abstract class WordRoomDatabase extends RoomDatabase { public abstract WordDao wordDao(); }
- 42. Step 4: Create Database @Database(entities = {Word.class}, version = 1) public abstract class WordRoomDatabase extends RoomDatabase { public abstract WordDao wordDao(); private static volatile WordRoomDatabase INSTANCE; static WordRoomDatabase getDatabase(final Context context) { if (INSTANCE == null) { synchronized (WordRoomDatabase.class) { if (INSTANCE == null) { // Create database here INSTANCE = Room.databaseBuilder(context.getApplicationContext(), WordRoomDatabase.class, "word_database") .addCallback(sRoomDatabaseCallback) .build(); } } } return INSTANCE; } }
- 43. Step 5: Update Repository public class WordRepository { private WordDao mWordDao; private LiveData<List<Word>> mAllWords; }
- 44. Step 5: Update Repository public class WordRepository { private WordDao mWordDao; private LiveData<List<Word>> mAllWords; public WordRepository(Application application) { WordRoomDatabase db = WordRoomDatabase.getDatabase(application); mWordDao = db.wordDao(); mAllWords = mWordDao.getAllWords(); } public LiveData<List<Word>> getAllWords() { return mAllWords; } public void insert(Word word) { new insertAsyncTask(mWordDao).execute(word); } }
- 45. Step 6: Testing DAO @RunWith(AndroidJUnit4.class) public class WordDaoTest { private WordDao mWordDao; private WordRoomDatabase mDb; @Before public void createDb() { Context context = InstrumentationRegistry.getTargetContext(); mDb = Room.inMemoryDatabaseBuilder(context, WordRoomDatabase.class) // Allowing main thread queries, just for testing. .allowMainThreadQueries() .build(); mWordDao = mDb.wordDao(); } @After public void closeDb() { mDb.close(); } }
- 46. Step 6: Testing DAO @RunWith(AndroidJUnit4.class) public class WordDaoTest { private WordDao mWordDao; private WordRoomDatabase mDb; @Before public void createDb() { Context context = InstrumentationRegistry.getTargetContext(); mDb = Room.inMemoryDatabaseBuilder(context, WordRoomDatabase.class) // Allowing main thread queries, just for testing. .allowMainThreadQueries() .build(); mWordDao = mDb.wordDao(); } @After public void closeDb() { mDb.close(); } @Test public void insertAndGetWord() throws Exception { Word word = new Word("word"); mWordDao.insert(word); List<Word> allWords = LiveDataTestUtil.getValue (mWordDao.getAlphabetizedWords()); assertEquals(allWords.get(0).getWord(), word.getWord()); } }
- 47. Step 7: Clean up - Remove unused classes replaced by Room. (i.e: any class extends SQLiteHelper) - More complex project: - https://medium.com/androiddevelopers/incrementally-migrate-from-sqlite-to-room-66c2f655b377
- 53. Codelab - https://codelabs.developers.google.com/codelabs/android-lifecycles/#1 - https://codelabs.developers.google.com/codelabs/android-persistence/#0 - https://codelabs.developers.google.com/codelabs/android-room-with-a-view/#0 - https://codelabs.developers.google.com/codelabs/android-paging/#0
- 54. Q&A