Persistency in Android

Persistency solutions in Android, from Shared Preferences to SQLite and to new Room.
When to use each solution?
How the magic behind Room is made?

Transcript

1. Lecture #8 Persistency 8 1
2. First, 2
3. Mentor @ Academy 3 Daniel Szasz Android Kotlin & Flutter Server Java & JS
4. 4 Android Academy Staff Yonatan Levin R&D Team Lead @ Monday.com Eden Machluf Mobile developer Refael Ozeri Founder & CEO @ Hero Apps Artyom Okun Mobile Software Engineer @ Wizdo
5. 5 Fundamentals Squad Hadas Peled Mobile Software Engineer @ CropX Gil Goldzweig Android tech lead @ Takeaway.com
6. Mentors Alexey Korolev Alex Vainshtein Ali Asadi Tiferet Cohen Hezi Dimri Shahar Barsheshet Berry Ventura Lev Avishay Peretz Andrew Lebedev Eugene Rozenberg David Vardi Sigal Levi Alex Cohn Nitzan Werber Orit Malki Vitaliy Abramov Shahar Ben Moshe Regev Avraham Aleksey Grach Gilad Levinson Daniel Szasz 6
7. Mentors • Aviram Peretz • Alex Vainshtein • Andrey Oleynik • Alex Cohn • Daniel Szasz • Gilad Levinson • Roi Bareket • Vova Hotyakov • Maxim Waitzman • Elad Jarby • Alexander Ferents • David Vardi • Hezi Dimri • Tiferet Cohen • Nitzan Werber • Gidi Shwartzman • Berry Ventura Lev • Regev Avraham • Vitaliy Abramov • Orit Malki • Leonid Shlafman • Alexey Korolev • Ali Asadi • Aleksey Grach • Yamin Elmakis • Avishay Peretz • Shahar ben Moshe • Eugene Rozenberg • Andrew Lebedev • Dan Gladshtein • Shahar Barsheahet • Sigal Levi 7 https://forms.gle/5MDJbwtUXXCQLSYS6
8. 8 Exercise Squad Alexey Korolev AT&T Yamin Elmakis Here Amit Frishberg Monday Vova Hotyakov Discount
9. https://kahoot.it 9
10. Idea pitching Sta ing next week! https://forms.gle/rtyV4zBpqn9umpS89
11. Looking for Teammates? 1. Prepare very short idea presentation in Google Slides (up to 3 pages): 1. Idea Explanation 2. Short self introduction (Who are you?) 3. Who you are looking for? 4. Contact details
12. Looking for Teammates? 1. Prepare very short idea presentation in Google Slides (up to 3 pages): 1. Idea Explanation 2. Short self introduction (Who are you?) 3. Who you are looking for? 4. Contact details 2. Submit the Pitch Request Form - https://forms.gle/rtyV4zBpqn9umpS89
13. Looking for Teammates? 1. Prepare very short idea presentation in Google Slides (up to 3 pages): 1. Idea Explanation 2. Short self introduction (Who are you?) 3. Who you are looking for? 4. Contact details 2. Submit the Pitch Request Form - https://forms.gle/rtyV4zBpqn9umpS89 3. Present it at the beginning of the lecture - 1 minute “Elevator Pitch”
14. What are we going to do today? 14
15. Persistency Activity LifeCycle SharedPreferences SQL SQLite/Room 15
16. Activity Lifecycle : Why Should I Care? 16
17. Activity Lifecycle : Why Should I Care? 17 Because we are awesome developers
18. Android Memory Management Recent Apps 18
19. Android Memory Management Switching back to a recent app 19
20. Android Memory Management Killing App 20
21. Android Process Hierarchy Ian Lake - Who lives and who dies? Process priorities on Android 21
22. Why Should I Care - Resources ? • Release resources ◦ battery ◦ GPS ◦ network ◦ cpu ◦ memory 22
23. Why Should I Care - Back to old state • Preserve user state - return to application after long time, classic examples: ◦ screen rotation ◦ answer to a call ◦ opening app from notification 23
24. Why Should I Care - Stability & Quality? • Stability - crash free when switching apps • Google Play - Android Vitals ◦ crashes ◦ ANR 24
25. Service Activity - UI Entry Point Content Provider Broadcast Receiver Activity 25
26. Main Entry Point 26
27. Specific Task Entry Point 27
29. OS created the activity, Activity “constructor” Activity override fun onCreate(savedInstanceState: Bundle?) CREATED 29
30. Activity is visible Activity override fun onCreate(savedInstanceState: Bundle?) override fun onStart() STARTED 30
31. Activity is in the foreground (focused) Activity override fun onCreate(savedInstanceState: Bundle?) override fun onStart() override fun onResume() RESUMED 31
33. Activity visible but not in foreground Activity override fun onPause() PAUSED 33
34. Activity is not visible Activity override fun onPause() override fun onStop() STOPPED 34
35. Activity shut down Activity DESTROYED override fun onDestroy() - finish() - Back button (default behaviour) - ActivityManager decides to kill - Process killed * Not always called 35
37. Switching Activities Activity A Activity B startActivity(Intent(this, ActivityB::class.java)); RESUMED 37
38. Activity A Lifecycle Activity A Activity B startActivity(Intent(this, ActivityB::class.java)); override fun onPause() PAUSED 38
39. Activity A Lifecycle Activity A Activity B startActivity(Intent(this, ActivityB::class.java)); override fun onPause() override fun onStop() STOPPED 39
40. Activity B Lifecycle Activity A Activity B startActivity(Intent(this, ActivityB::class.java)); override fun onCreate(savedInstanceState: Bundle?) STOPPED 40 CREATED
41. Activity B Lifecycle Activity A Activity B startActivity(Intent(this, ActivityB::class.java)); override fun onCreate(savedInstanceState: Bundle?) override fun onStart() STOPPED 41 STARTED
42. Activity B Lifecycle Activity A Activity B startActivity(Intent(this, ActivityB::class.java)); override fun onCreate(savedInstanceState: Bundle?) override fun onStart() STOPPED 42 RESUMED
43. Lifecycle simple 43
45. Let’s Rotate 45
48. Screen Rotation Lifecycle onSaveInstanceState() * Always called before onStop onStop() onDestroy() onCreate(savedInstanceState: Bundle?) loadMovies() Running Shut down Re-Create Running 48
49. Persistency 49
50. Let’s Persist! • Long term memory • Storage for data • Cache - faster loading time 50
51. How Much Faster? L1 cache reference ......................... 0.5 ns L2 cache reference ........................... 7 ns Main memory reference ...................... 100 ns Compress 1K bytes with Zippy ............. 3,000 ns = 3 µs Send 2K bytes over 1 Gbps network ....... 20,000 ns = 20 µs SSD random read ........................ 150,000 ns = 150 µs Read 1 MB sequentially from memory ..... 250,000 ns = 250 µs Round trip within same datacenter ...... 500,000 ns = 0.5 ms Read 1 MB sequentially from SSD* ..... 1,000,000 ns = 1 ms Disk seek ........................... 10,000,000 ns = 10 ms Read 1 MB sequentially from disk .... 20,000,000 ns = 20 ms Send packet CA->Netherlands->CA .... 150,000,000 ns = 150 ms Number Every Programmer Must Know https://gist.github.com/hellerbarde/2843375 51
54. SharedPreferences 54
55. Key Value XML based Storage • Small storage space • No structure (key-value) • Not secured • Primitive types (booleans, floats, ints, longs, and strings) • Complex objects serialize to String 55
56. Creating SharedPreferences val sharedPreferences: SharedPreferences! = PreferenceManager.getDefaultSharedPreferences(context); from androidx.preference (old one is deprecated since API 29) 56
57. Editing val sharedPref: SharedPreferences! = PreferenceManager.getDefaultSharedPreferences(context) val editor: SharedPreferences.Editor! = sharedPref.edit() 57
58. Adding Data val sharedPref: SharedPreferences! = PreferenceManager.getDefaultSharedPreferences(context) val editor: SharedPreferences.Editor! = sharedPref.edit() editor.putString("KEY_STRING","Android Academy is awesome!") editor.putInt("KEY_INT",1) editor.putFloat("KEY_FLOAT",1F) editor.putBoolean("KEY_BOOLEAN",true) editor.putLong("KEY_LONG",1L) editor.putStringSet("KEY_SET",new ArraySet<String>()) 58
59. Saving Data - Commit val sharedPref: SharedPreferences! = PreferenceManager.getDefaultSharedPreferences(context) val editor: SharedPreferences.Editor! = sharedPref.edit() editor.putInt("KEY_INT",1) ... boolean success = editor.commit() //blocking, returns success indication 59
60. Saving Data - Apply val sharedPref: SharedPreferences! = PreferenceManager.getDefaultSharedPreferences(context) val editor: SharedPreferences.Editor! = sharedPref.edit() editor.putInt("KEY_INT",1) ... editor.apply(); //background thread, no return value 60
61. Saving Data - Commit vs Apply • commit - we know the result • apply - we have no idea what happened. 61
62. Loading Data 62 sharedPref: SharedPreferences! = PreferenceManager.getDefaultSharedPreferences(context); myString: String = sharedPref.getString("KEY_STRING", null) myInt: int = sharedPref.getInt("KEY_INT", 0) myFloat: Float = sharedPref.getFloat("KEY_FLOAT", 0F) myBoolean: Boolean = sharedPref.getBoolean("KEY_BOOLEAN", false) myLong: Long = sharedPref.getLong("KEY_LONG", 0L) myStringSet: Set<String> = sharedPref.getStringSet("KEY_SET", null)
63. A Look From The Inside 63
64. A Look From The Inside - XML 64
65. When to use Shared Preferences • User preferences! • Global state - user id, user token, isLoggedIn etc. • Small, unstructured data • Unsecured - very easy to take a look inside. 65
66. AndroidManifest - backup 66 <manifest ... > ... <application android:allowBackup="true" ... > ... </application> </manifest>
69. Database 69
70. Database Database: A structured set of data Relational database: A Database which uses tables and relations to organize the data, Usually uses SQL for operations Relational Database management system: A program (or less) that implements a Relational Database. Common vendors:PostgreSQL, Oracle, MySQL, Microsoft SQL Server 70
71. Database 71
72. Tables 72
73. When to use a Database - requirements • Large datasets • Structured data • Cache / Preload data 73
74. When to use a Database - results • Better loading times • Better battery utilization • Better network utilization by saving traffic 74
75. Our Database SQLite is a mini-RDBMS. Unlike most: - Serverless (Runs in your process, not on its own) - Zero-Configuration - Most widely deployed database Get to know it better: https://www.sqlite.org/ 75
76. SQL - Structured Query Language the language to communicate with database. 76
77. Creating our table CREATE TABLE Movies ( movieId INTEGER PRIMARY KEY, name TEXT, imageUri TEXT, releaseDate TEXT, popularity REAL ) Read More: https://www.sqlite.org/lang_createtable.html 77
78. CREATE TABLE statement CREATE TABLE Movies ( movieId INTEGER PRIMARY KEY, name TEXT, imageUri TEXT, releaseDate TEXT, popularity REAL ) Read More: https://www.sqlite.org/lang_createtable.html 78
79. Table Name CREATE TABLE Movies ( movieId INTEGER PRIMARY KEY, name TEXT, imageUri TEXT, releaseDate TEXT, popularity REAL ) Read More: https://www.sqlite.org/lang_createtable.html 79
80. Primary Key CREATE TABLE Movies ( movieId INTEGER PRIMARY KEY, name TEXT, imageUri TEXT, releaseDate TEXT, popularity REAL ) Read More: https://www.sqlite.org/lang_createtable.html 80
81. Column Types CREATE TABLE Movies ( movieId INTEGER PRIMARY KEY, name TEXT, imageUri TEXT, releaseDate TEXT, popularity REAL ) Read More: https://www.sqlite.org/lang_createtable.html 81
82. Column Types CREATE TABLE Movies ( movieId INTEGER PRIMARY KEY, name TEXT, imageUri TEXT, releaseDate TEXT, popularity REAL ) Read More: https://www.sqlite.org/lang_createtable.html 82
83. Column Types CREATE TABLE Movies ( movieId INTEGER PRIMARY KEY, name TEXT, imageUri TEXT, releaseDate TEXT, popularity REAL ) Read More: https://www.sqlite.org/lang_createtable.html 83
84. movieId name imageUri releaseDate popularity 297802 Aquaman https://image.tmdb.org/ t/p/w342/i2dF9UxOeb77CA JrOflj0RpqJRF.jpg 2018-12-07 616.683 299536 Avengers: Infinity War https://image.tmdb.org/ t/p/w342/7WsyChQLEftFiD OVTGkv3hFpyyt.jpg 2018-04-25 128.347 324857 Spider-Man: Into the Spider-Verse https://image.tmdb.org/ t/p/w342/laMM4lpQSh5z6K IBPwWogkjzBVQ.jpg 2018-12-07 152.037 335983 Venom https://image.tmdb.org/ t/p/w342/2uNW4WbgBXL25B AbXGLnLqX71Sw.jpg 2018-10-03 227.227 338952 Fantastic Beasts: The Crimes of Grindelwald https://image.tmdb.org/ t/p/w342/kQKcbJ9uYkTQql 2R8L4jTUz7l90.jpg 2018-11-14 272.343 84
86. Actions: - Insert - Adds records to tables. - Update - modifies values in existing records - Select - gets part of the table - Delete - Removes records from tables. 86
87. Select - gets part of the table SELECT ( * | [column, column]) FROM (table) WHERE (condition) ORDER BY (column) (ASC | DESC) This is super-simplified. Read more: https://www.sqlite.org/lang_select.html 87
88. Select SELECT * FROM Movies WHERE name = ’Aquaman’ movieId name imageUri releaseDate popularity 297802 Aquaman https://image.tmdb .org/t/p/w342/i2dF 9UxOeb77CAJrOflj0R pqJRF.jpg 2018-12-07 616.683 88
89. Select SELECT * FROM Movies ORDER BY popularity ASC movieId name imageUri releaseDate popularity 299536 Avengers: Infinity War https://image.tmdb.org/t/p/w342/7Wsy ChQLEftFiDOVTGkv3hFpyyt.jpg 2018-04-25 128.347 324857 Spider-Man: Into the Spider-Verse https://image.tmdb.org/t/p/w342/laMM4 lpQSh5z6KIBPwWogkjzBVQ.jpg 2018-12-07 152.037 335983 Venom https://image.tmdb.org/t/p/w342/2uNW 4WbgBXL25BAbXGLnLqX71Sw.jpg 2018-10-03 227.227 338952 Fantastic Beasts: The Crimes of Grindelwald https://image.tmdb.org/t/p/w342/kQKcb J9uYkTQql2R8L4jTUz7l90.jpg 2018-11-14 272.343 297802 Aquaman https://image.tmdb.org/t/p/w342/i2dF9 UxOeb77CAJrOflj0RpqJRF.jpg 2018-12-07 616.683 89
90. Select SELECT * FROM Movies WHERE name LIKE ’% the %’ movieId name imageUri releaseDate popularity 338952 Fantastic Beasts: the Crimes of Grindelwald https://image.tmd b.org/t/p/w342/k QKcbJ9uYkTQql 2R8L4jTUz7l90.j pg 2018-11-14 272.343 324857 Spider-Man: Into the Spider-Verse https://image.tmd b.org/t/p/w342/la MM4lpQSh5z6KI BPwWogkjzBVQ. jpg 2018-12-07 152.037 90
91. Select SELECT * FROM Movies WHERE title LIKE ’% the %’ AND popularity > 200 movieId name imageUri releaseDate popularity 338952 Fantastic Beasts: the Crimes of Grindelwald https://image.tmd b.org/t/p/w342/k QKcbJ9uYkTQql 2R8L4jTUz7l90.j pg 2018-11-14 272.343 91
93. Databases - The Old Way 93
94. Declaring Contract Class class MoviesContract private constructor() { } 94
95. Implementing BaseColumns class MoviesContract private constructor() { object MovieEntry : BaseColumns { } } 95
96. Table Name class MoviesContract private constructor() { object MovieEntry : BaseColumns { const val TABLE_NAME = "MOVIE_ENTRY" } } 96
97. Columns Names class MoviesContract private constructor() { object MovieEntry : BaseColumns { const val TABLE_NAME = "MOVIE_ENTRY" const val COLUMN_NAME_NAME = "name" const val COLUMN_NAME_CONTENT = "content" const val COLUMN_NAME_IMAGE_URI = "image_uri" const val COLUMN_NAME_RELEASE_DATE = "release_date" } } 97
98. We have a contract. Time for tables 98
99. Create Table SQL private val SQL_CREATE_ENTRIES = "CREATE TABLE " + MovieEntry.TABLE_NAME + " (" + MovieEntry._ID + " INTEGER PRIMARY KEY," + MovieEntry.COLUMN_NAME_NAME + " TEXT," + MovieEntry.COLUMN_NAME_CONTENT + " TEXT," + MovieEntry.COLUMN_NAME_IMAGE_URI + " TEXT," + MovieEntry.COLUMN_NAME_RELEASE_DATE + " TEXT)"; private val SQL_DELETE_ENTRIES = "DROP TABLE IF EXISTS " + MovieEntry.TABLE_NAME; 99
100. SQLiteOpenHelper 100 class MoviesDbHelper(context: Context?) : SQLiteOpenHelper(context, DATABASE_NAME, null, DATABASE_VERSION) { companion object { private const val DATABASE_NAME = "MoviesDb.db" private const val DATABASE_VERSION = 1 } }
101. SQLiteOpenHelper 101 class MoviesDbHelper(context: Context?) : SQLiteOpenHelper(context, DATABASE_NAME, null, DATABASE_VERSION) { companion object { private const val DATABASE_NAME = "MoviesDb.db" private const val DATABASE_VERSION = 1 } }
102. SQLiteOpenHelper 102 class MoviesDbHelper(context: Context?) : SQLiteOpenHelper(context, DATABASE_NAME, null, DATABASE_VERSION) { override fun onCreate(db: SQLiteDatabase) { db.execSQL(SQL_CREATE_ENTRIES) } companion object { private const val DATABASE_NAME = "MoviesDb.db" private const val DATABASE_VERSION = 1 } }
103. SQLiteOpenHelper 103 class MoviesDbHelper(context: Context?) : SQLiteOpenHelper(context, DATABASE_NAME, null, DATABASE_VERSION) { override fun onCreate(db: SQLiteDatabase) { db.execSQL(SQL_CREATE_ENTRIES) } override fun onUpgrade(db: SQLiteDatabase, oldVersion: int, newVersion: int){ } companion object { private const val DATABASE_NAME = "MoviesDb.db" private const val DATABASE_VERSION = 1 } }
104. Save Data 104
105. Save Data private fun saveData(moviesList:List<MovieModel>) { } 105
106. Get Writable Database private fun saveData(moviesList:List<MovieModel>) { val db = MoviesDbHelper.getInstance(this).getWritableDatabase() db.close() } 106
107. Transaction private fun saveData(moviesList:List<MovieModel>) { val db = MoviesDbHelper.getInstance(this).getWritableDatabase() db.beginTransaction() try{ db.setTransactionSuccessful() }finally{ db.endTransaction() } db.close() } 107
108. Filling Content Value private fun saveData(moviesList:List<MovieModel>) { val db = MoviesDbHelper.getInstance(this).getWritableDatabase() db.beginTransaction() try{ val values = ContentValues() for (movie in moviesList){ values.put(MovieEntry.COLUMN_NAME_NAME, movie.getName()) ... } db.setTransactionSuccessful() }finally{ db.endTransaction() } db.close() } 108
109. Inserting Values private fun saveData(moviesList:List<MovieModel>) { val db = MoviesDbHelper.getInstance(this).getWritableDatabase() db.beginTransaction() try{ val values = ContentValues() for (movie in moviesList){ values.put(MovieEntry.COLUMN_NAME_NAME, movie.getName()) ... db.insert(MovieEntry.TABLE_NAME, null, values) } db.setTransactionSuccessful() }finally{ db.endTransaction() } db.close() } 109
110. Restore Data 110
111. Restore Data private fun restoreData():List<MovieModel> { } 111
112. Get Readable Database private fun restoreData():List<MovieModel> { val db = MoviesDbHelper.getInstance(this).getReadableDatabase() } 112
113. Projection Array private fun restoreData():List<MovieModel> { val db = MoviesDbHelper.getInstance(this).getReadableDatabase() val projection = arrayOf<String>(MovieEntry.COLUMN_NAME_NAME, MovieEntry.COLUMN_NAME_CONTENT, MovieEntry.COLUMN_NAME_IMAGE_URI, MovieEntry.COLUMN_NAME_RELEASE_DATE) } 113
114. Query private fun restoreData() { val cursor = db.query( MovieEntry.TABLE_NAME, projection, null, null, null, null, null) } 114
115. Cursor random read-write access to the result set returned by a database query 115
116. Query 116
117. Iterating Over Values private fun restoreData(){ } 117
118. Getting column index private fun restoreData(){ val columnIndexName = cursor.getColumnIndexOrThrow(MovieEntry.COLUMN_NAME_NAME) val columnIndexContent = cursor.getColumnIndexOrThrow(MovieEntry.COLUMN_NAME_CONTENT) val columnIndexImageUri = cursor.getColumnIndexOrThrow(MovieEntry.COLUMN_NAME_IMAGE_URI) val columnIndexReleaseDate = cursor.getColumnIndexOrThrow(MovieEntry.COLUMN_NAME_RELEASE_DATE) } 118
119. Getting cursor 119 private fun restoreData(){ val columnIndexName = cursor.getColumnIndexOrThrow(MovieEntry.COLUMN_NAME_NAME) ... val cursor = db.query(MovieEntry.TABLE_NAME,projection,null, null, null, null, null) cursor.close() }
120. Creating result list private fun restoreData(){ val columnIndexName = cursor.getColumnIndexOrThrow(MovieEntry.COLUMN_NAME_NAME) ... val cursor = db.query(MovieEntry.TABLE_NAME,projection,null, null, null, null, null) val moviesList = ArrayList() cursor.close() } 120
121. Iterating Over Cursor private fun restoreData(){ ... if (cursor.getCount() > 0){ while (cursor.moveToNext()){ val name = cursor.getString(columnIndexName) val content = cursor.getString(columnIndexContent) val url = cursor.getString(columnIndexImageUri) val releaseDate = cursor.getString(columnIndexReleaseDate) } } ... } 121
122. Creating MovieModel private fun restoreData(){ ... if (cursor.getCount() > 0){ while (cursor.moveToNext()){ val name = cursor.getString(columnIndexName) val content = cursor.getString(columnIndexContent) val url = cursor.getString(columnIndexImageUri) val releaseDate = cursor.getString(columnIndexReleaseDate) moviesList.add(MovieModel(name, content, url, releaseDate)) } } ... } 122
123. Close cursor private fun restoreData(){ ... val cursor = db.query(MovieEntry.TABLE_NAME,projection,null, null, null, null, null) if (cursor.getCount() > 0){ while (cursor.moveToNext()){ ... } } cursor.close() } 123
124. Updating UI private fun restoreData(){ ... updateUI(moviesList) } 124
127. There is a Room for improvement! 127
128. Android Architecture Components 128
129. Together or Separately. 129
130. Room Persistence Library 130
132. Entities -> Tables 132
133. MovieModel Entity @Parcelize @Entity data class MovieModel( @PrimaryKey val movieId: Int, val name: String, val imageUrl: String, val overview: String?, val backImageUrl: String, val releaseDate: String, val popularity: Double ) : Parcelable 133
134. Entity @Parcelize @Entity data class MovieModel( @PrimaryKey val movieId: Int, val name: String, val imageUrl: String, val overview: String?, val backImageUrl: String, val releaseDate: String, val popularity: Double ) : Parcelable 134
135. Primary Key @Parcelize @Entity data class MovieModel( @PrimaryKey val movieId: Int, val name: String, val imageUrl: String, val overview: String?, val backImageUrl: String, val releaseDate: String, val popularity: Double ) : Parcelable 135
136. Columns @Parcelize @Entity data class MovieModel( @PrimaryKey val movieId: Int, val name: String, val imageUrl: String, val overview: String?, val backImageUrl: String, val releaseDate: String, val popularity: Double ) : Parcelable 136
137. DAO - Data Access Object 137
138. Data Access Object Database Entity Data Access Object Mapper SQL Query Raw Data Raw Data Entity Object 138
139. Data Access Object @Dao interface MovieDao { } 139
140. Raw Query - Select @Dao interface MovieDao { @Query("SELECT * FROM MovieModel ORDER BY popularity DESC") fun getAll(): List<MovieModel> } 140
141. Insert - Strategy ABORT @Dao interface MovieDao { @Query("SELECT * FROM MovieModel ORDER BY popularity DESC") fun getAll(): List<MovieModel> @Insert(onConflict = OnConflictStrategy.ABORT) fun insertAll(movies: Collection<MovieModel>) } 141
142. Insert - Strategy FAIL @Dao interface MovieDao { @Query("SELECT * FROM MovieModel ORDER BY popularity DESC") fun getAll(): List<MovieModel> @Insert(onConflict = OnConflictStrategy.FAIL) fun insertAll(movies: Collection<MovieModel>) } 142
143. Insert - Strategy IGNORE @Dao interface MovieDao { @Query("SELECT * FROM MovieModel ORDER BY popularity DESC") fun getAll(): List<MovieModel> @Insert(onConflict = OnConflictStrategy.IGNORE) fun insertAll(movies: Collection<MovieModel>) } 143
144. Insert - Strategy REPLACE @Dao interface MovieDao { @Query("SELECT * FROM MovieModel ORDER BY popularity DESC") fun getAll(): List<MovieModel> @Insert(onConflict = OnConflictStrategy.REPLACE) fun insertAll(movies: Collection<MovieModel>) } 144
145. Insert - Strategy ROLLBACK @Dao interface MovieDao { @Query("SELECT * FROM MovieModel ORDER BY popularity DESC") fun getAll(): List<MovieModel> @Insert(onConflict = OnConflictStrategy.ROLLBACK) fun insertAll(movies: Collection<MovieModel>) } 145
146. Raw Query - Delete @Dao interface MovieDao { @Query("SELECT * FROM MovieModel ORDER BY popularity DESC") fun getAll(): List<MovieModel> @Insert(onConflict = OnConflictStrategy.REPLACE) fun insertAll(movies: Collection<MovieModel>) @Query("DELETE FROM MovieModel") fun deleteAll() } 146
147. Raw Query - Select with LIKE @Dao public interface MovieDao { @Query("SELECT * FROM movieModel WHERE name LIKE :name LIMIT 1") MovieModel findByName(String name); } 147
148. Raw Query - Select with array @Dao public interface MovieDao { @Query("SELECT * FROM movieModel WHERE name LIKE :name LIMIT 1") MovieModel findByName(String name); @Query("SELECT * FROM movieModel WHERE movieId IN (:movieIds)") List<MovieModel> loadAllByIds(string[] movieIds); } 148
149. Syntax Errors Highlight @Dao interface MovieDao { @Insert(onConflict = OnConflictStrategy.REPLACE) fun insertAll(movies: Collection<MovieModel>) @Query("DELETE FROM MovieModel") fun deleteAll() } 149
150. Syntax Errors Highlight @Dao interface MovieDao { @Insert(onConflict = OnConflictStrategy.REPLACE) fun insertAll(movies: Collection<MovieModel>) @Query("DELETE FROM MovieModel") fun deleteAll() } 150
151. How The Magic Works? 151
152. How The Magic Works? @Override public void insertAll(final Collection<MovieModel> movies) { __db.assertNotSuspendingTransaction(); __db.beginTransaction(); try { __insertionAdapterOfMovieModel.insert(movies); __db.setTransactionSuccessful(); } finally { __db.endTransaction(); } } 152
153. How The Magic Works? @Override public void deleteAll() { __db.assertNotSuspendingTransaction(); final SupportSQLiteStatement _stmt = __preparedStmtOfDeleteAll.acquire(); __db.beginTransaction(); try { _stmt.executeUpdateDelete(); __db.setTransactionSuccessful(); } finally { __db.endTransaction(); __preparedStmtOfDeleteAll.release(_stmt); } } 153
154. How The Magic Works? @Override public List<MovieModel> getAll() { final String _sql = "SELECT * FROM MovieModel ORDER BY popularity DESC"; final RoomSQLiteQuery _statement = RoomSQLiteQuery.acquire(_sql, 0); __db.assertNotSuspendingTransaction(); final Cursor _cursor = DBUtil.query(__db, _statement, false, null); try { final int _cursorIndexOfMovieId = CursorUtil.getColumnIndexOrThrow(_cursor, "movieId"); ... final List<MovieModel> _result = new ArrayList<MovieModel>(_cursor.getCount()); while(_cursor.moveToNext()) { final MovieModel _item; final int _tmpMovieId; _tmpMovieId = _cursor.getInt(_cursorIndexOfMovieId); final String _tmpName; _tmpName = _cursor.getString(_cursorIndexOfName); ... _item = new MovieModel(_tmpMovieId,_tmpName,_tmpImageUrl,_tmpOverview,_tmpBackImageUrl,_tmpReleaseDate,_tmpPopularity); _result.add(_item); } return _result; } finally { _cursor.close(); _statement.release(); } } 154
156. RoomDatabase 156
157. Declaring a Database @Database(entities = [MovieModel::class, TrailerModel::class], version = 1) abstract class AppDatabase : RoomDatabase() { abstract fun movieDao(): MovieDao? abstract fun videoDao(): TrailerDao? companion object { private const val DATABASE_NAME = "movies" private var INSTANCE: AppDatabase? = null fun getInstance(context: Context): AppDatabase? { if (INSTANCE == null) { INSTANCE = Room.databaseBuilder( context.applicationContext, AppDatabase::class.java, DATABASE_NAME ) .allowMainThreadQueries() .fallbackToDestructiveMigration() .build() } return INSTANCE } fun destroyInstance() { INSTANCE = null } } } 157
158. Declaring a Database @Database(entities = [MovieModel::class], version = 1) abstract class AppDatabase : RoomDatabase() { abstract fun movieDao(): MovieDao? abstract fun videoDao(): TrailerDao? companion object { private const val DATABASE_NAME = "movies" private var INSTANCE: AppDatabase? = null fun getInstance(context: Context): AppDatabase? { if (INSTANCE == null) { INSTANCE = Room.databaseBuilder( context.applicationContext, AppDatabase::class.java, DATABASE_NAME ) .allowMainThreadQueries() .fallbackToDestructiveMigration() .build() } return INSTANCE } fun destroyInstance() { INSTANCE = null } } } 158
159. Adding DAOs @Database(entities = [MovieModel::class, TrailerModel::class], version = 1) abstract class AppDatabase : RoomDatabase() { abstract fun movieDao(): MovieDao? companion object { private const val DATABASE_NAME = "movies" private var INSTANCE: AppDatabase? = null fun getInstance(context: Context): AppDatabase? { if (INSTANCE == null) { INSTANCE = Room.databaseBuilder( context.applicationContext, AppDatabase::class.java, DATABASE_NAME ) .allowMainThreadQueries() .fallbackToDestructiveMigration() .build() } return INSTANCE } fun destroyInstance() { INSTANCE = null } } } 159
160. Creating a Database @Database(entities = [MovieModel::class, TrailerModel::class], version = 1) abstract class AppDatabase : RoomDatabase() { ... fun getInstance(context: Context): AppDatabase? { if (INSTANCE == null) { INSTANCE = Room.databaseBuilder( context.applicationContext, AppDatabase::class.java, DATABASE_NAME ) .allowMainThreadQueries() .fallbackToDestructiveMigration() .build() } return INSTANCE } fun destroyInstance() { 160
161. Creating a Database @Database(entities = [MovieModel::class, TrailerModel::class], version = 1) abstract class AppDatabase : RoomDatabase() { ... fun getInstance(context: Context): AppDatabase? { if (INSTANCE == null) { INSTANCE = Room.databaseBuilder( context.applicationContext, AppDatabase::class.java, DATABASE_NAME ) .allowMainThreadQueries() .fallbackToDestructiveMigration() .build() } return INSTANCE } fun destroyInstance() { INSTANCE = null 161
162. Using Singleton @Database(entities = [MovieModel::class, TrailerModel::class], version = 1) abstract class AppDatabase : RoomDatabase() { ... fun getInstance(context: Context): AppDatabase? { if (INSTANCE == null) { INSTANCE = Room.databaseBuilder( context.applicationContext, AppDatabase::class.java, DATABASE_NAME ) .allowMainThreadQueries() .fallbackToDestructiveMigration() .build() } return INSTANCE } fun destroyInstance() { INSTANCE = null } } } 162
163. Saving Data 163
164. Saving Data private fun onDataReceivedFromServer(response: Response<MoviesListResult>) { main_progress.visibility = View.GONE response.body()?.let { val convertedList = MovieModelConverter.convertNetworkMovieToModel(it) movies.apply { clear() addAll(convertedList) } moviesList.adapter?.notifyDataSetChanged() AppDatabase.getInstance(this@MoviesActivity)?.movieDao()?.deleteAll() AppDatabase.getInstance(this@MoviesActivity)?.movieDao()?.insertAll(MoviesContent.movies) } } 164
165. Saving Data - receving from network private fun onDataReceivedFromServer(response: Response<MoviesListResult>) { main_progress.visibility = View.GONE response.body()?.let { val convertedList = MovieModelConverter.convertNetworkMovieToModel(it) movies.apply { clear() addAll(convertedList) } moviesList.adapter?.notifyDataSetChanged() AppDatabase.getInstance(this@MoviesActivity)?.movieDao()?.deleteAll() AppDatabase.getInstance(this@MoviesActivity)?.movieDao()?.insertAll(MoviesContent.movies) } } 165
166. Saving Data - updating the User private fun onDataReceivedFromServer(response: Response<MoviesListResult>) { main_progress.visibility = View.GONE response.body()?.let { val convertedList = MovieModelConverter.convertNetworkMovieToModel(it) movies.apply { clear() addAll(convertedList) } moviesList.adapter?.notifyDataSetChanged() AppDatabase.getInstance(this@MoviesActivity)?.movieDao()?.deleteAll() AppDatabase.getInstance(this@MoviesActivity)?.movieDao()?.insertAll(MoviesContent.movies) } } 166
167. Saving Data - delete existing data private fun onDataReceivedFromServer(response: Response<MoviesListResult>) { main_progress.visibility = View.GONE response.body()?.let { val convertedList = MovieModelConverter.convertNetworkMovieToModel(it) movies.apply { clear() addAll(convertedList) } moviesList.adapter?.notifyDataSetChanged() AppDatabase.getInstance(this@MoviesActivity)?.movieDao()?.deleteAll() AppDatabase.getInstance(this@MoviesActivity)?.movieDao()?.insertAll(MoviesContent.movies) } } 167
168. Saving Data - insert new data private fun onDataReceivedFromServer(response: Response<MoviesListResult>) { main_progress.visibility = View.GONE response.body()?.let { val convertedList = MovieModelConverter.convertNetworkMovieToModel(it) movies.apply { clear() addAll(convertedList) } moviesList.adapter?.notifyDataSetChanged() AppDatabase.getInstance(this@MoviesActivity)?.movieDao()?.deleteAll() AppDatabase.getInstance(this@MoviesActivity)?.movieDao()?.insertAll(MoviesContent.movies) } } 168
170. Restoring Data 170
171. Restoring Data private fun getCachedMoviesFromDataBase() { val cachedMovies: List<MovieModel>? = AppDatabase.getInstance(this)?.movieDao()?.getAll() cachedMovies?.let { movies.addAll(cachedMovies) moviesList.adapter?.notifyDataSetChanged() } } 171
172. Restoring Data - load from database private fun getCachedMoviesFromDataBase() { val cachedMovies: List<MovieModel>? = AppDatabase.getInstance(this)?.movieDao()?.getAll() cachedMovies?.let { movies.addAll(cachedMovies) moviesList.adapter?.notifyDataSetChanged() } } 172
173. Restoring Data - adding data to adapter private fun getCachedMoviesFromDataBase() { val cachedMovies: List<MovieModel>? = AppDatabase.getInstance(this)?.movieDao()?.getAll() cachedMovies?.let { movies.addAll(cachedMovies) moviesList.adapter?.notifyDataSetChanged() } } 173
174. Restoring Data - notify to update UI private fun getCachedMoviesFromDataBase() { val cachedMovies: List<MovieModel>? = AppDatabase.getInstance(this)?.movieDao()?.getAll() cachedMovies?.let { movies.addAll(cachedMovies) moviesList.adapter?.notifyDataSetChanged() } } 174
176. Exercise 8 176