preparing the migration to Room database

app/build.gradle

@@ -1,6 +1,7 @@
 apply plugin: 'com.android.application'
 apply plugin: 'kotlin-android'
 apply plugin: 'kotlin-android-extensions'
+apply plugin: 'kotlin-kapt'
 
 def keystorePropertiesFile = rootProject.file("keystore.properties")
 def keystoreProperties = new Properties()
@@ -51,4 +52,8 @@ android {
 
 dependencies {
     implementation 'com.simplemobiletools:commons:5.3.13'
+
+    kapt 'androidx.room:room-compiler:2.0.0'
+    implementation 'androidx.room:room-runtime:2.0.0'
+    annotationProcessor 'androidx.room:room-compiler:2.0.0'
 }

app/src/main/kotlin/com/simplemobiletools/notes/pro/activities/MainActivity.kt

@@ -25,6 +25,7 @@ import com.simplemobiletools.commons.views.MyEditText
 import com.simplemobiletools.notes.pro.BuildConfig
 import com.simplemobiletools.notes.pro.R
 import com.simplemobiletools.notes.pro.adapters.NotesPagerAdapter
+import com.simplemobiletools.notes.pro.databases.NotesDatabase
 import com.simplemobiletools.notes.pro.dialogs.*
 import com.simplemobiletools.notes.pro.extensions.config
 import com.simplemobiletools.notes.pro.extensions.dbHelper
@@ -110,6 +111,13 @@ class MainActivity : SimpleActivity() {
         storeStateVariables()
     }
 
+    override fun onDestroy() {
+        super.onDestroy()
+        if (!isChangingConfigurations) {
+            NotesDatabase.destroyInstance()
+        }
+    }
+
     override fun onCreateOptionsMenu(menu: Menu): Boolean {
         menuInflater.inflate(R.menu.menu, menu)
         menu.apply {
@@ -218,7 +226,7 @@ class MainActivity : SimpleActivity() {
             if (it as Int == 0) {
                 displayNewNoteDialog(text)
             } else {
-                updateSelectedNote(notes[it - 1].id)
+                updateSelectedNote(notes[it - 1].id!!)
                 addTextToCurrentNote(if (mCurrentNote.value.isEmpty()) text else "\n$text")
             }
         }
@@ -249,7 +257,7 @@ class MainActivity : SimpleActivity() {
 
             onPageChangeListener {
                 mCurrentNote = mNotes[it]
-                config.currentNoteId = mCurrentNote.id
+                config.currentNoteId = mCurrentNote.id!!
             }
         }
 
@@ -561,13 +569,13 @@ class MainActivity : SimpleActivity() {
     }
 
     private fun doDeleteNote(note: Note, deleteFile: Boolean) {
-        dbHelper.deleteNote(mCurrentNote.id)
+        dbHelper.deleteNote(mCurrentNote.id!!)
         mNotes = dbHelper.getNotes()
 
         val firstNoteId = mNotes[0].id
-        updateSelectedNote(firstNoteId)
+        updateSelectedNote(firstNoteId!!)
         if (config.widgetNoteId == note.id) {
-            config.widgetNoteId = mCurrentNote.id
+            config.widgetNoteId = mCurrentNote.id!!
             updateWidgets()
         }
 

app/src/main/kotlin/com/simplemobiletools/notes/pro/activities/WidgetConfigureActivity.kt

@@ -89,7 +89,7 @@ class WidgetConfigureActivity : SimpleActivity() {
     private fun showNoteSelector() {
         val items = ArrayList<RadioItem>()
         mNotes.forEach {
-            items.add(RadioItem(it.id, it.title))
+            items.add(RadioItem(it.id!!, it.title))
         }
 
         RadioGroupDialog(this, items, mCurrentNoteId) {
@@ -99,7 +99,7 @@ class WidgetConfigureActivity : SimpleActivity() {
     }
 
     private fun updateCurrentNote(note: Note) {
-        mCurrentNoteId = note.id
+        mCurrentNoteId = note.id!!
         notes_picker_value.text = note.title
         val sampleValue = if (note.value.isEmpty() || mIsCustomizingColors) getString(R.string.widget_config) else note.value
         notes_view.text = sampleValue

app/src/main/kotlin/com/simplemobiletools/notes/pro/adapters/NotesPagerAdapter.kt

@@ -18,7 +18,7 @@ class NotesPagerAdapter(fm: FragmentManager, val notes: List<Note>, val activity
     override fun getItem(position: Int): NoteFragment {
         val bundle = Bundle()
         val id = notes[position].id
-        bundle.putInt(NOTE_ID, id)
+        bundle.putInt(NOTE_ID, id!!)
 
         if (fragments.containsKey(position)) {
             return fragments[position]!!

app/src/main/kotlin/com/simplemobiletools/notes/pro/databases/NotesDatabase.kt

@@ -0,0 +1,51 @@
+package com.simplemobiletools.notes.pro.databases
+
+import android.content.Context
+import androidx.room.Database
+import androidx.room.Room
+import androidx.room.RoomDatabase
+import androidx.sqlite.db.SupportSQLiteDatabase
+import com.simplemobiletools.notes.pro.interfaces.NotesDao
+import com.simplemobiletools.notes.pro.models.Note
+import com.simplemobiletools.notes.pro.objects.MyExecutor
+import java.util.concurrent.Executors
+
+@Database(entities = [Note::class], version = 1)
+abstract class NotesDatabase : RoomDatabase() {
+
+    abstract fun NotesDao(): NotesDao
+
+    companion object {
+        private var db: NotesDatabase? = null
+
+        fun getInstance(context: Context): NotesDatabase {
+            if (db == null) {
+                synchronized(NotesDatabase::class) {
+                    if (db == null) {
+                        db = Room.databaseBuilder(context.applicationContext, NotesDatabase::class.java, "notes.db")
+                                .setQueryExecutor(MyExecutor.myExecutor)
+                                .addCallback(object : Callback() {
+                                    override fun onCreate(db: SupportSQLiteDatabase) {
+                                        super.onCreate(db)
+                                        insertFirstNote()
+                                    }
+                                })
+                                .build()
+                        db!!.openHelper.setWriteAheadLoggingEnabled(true)
+                    }
+                }
+            }
+            return db!!
+        }
+
+        fun destroyInstance() {
+            db = null
+        }
+
+        private fun insertFirstNote() {
+            Executors.newSingleThreadExecutor().execute {
+
+            }
+        }
+    }
+}

app/src/main/kotlin/com/simplemobiletools/notes/pro/dialogs/OpenNoteDialog.kt

@@ -27,7 +27,7 @@ class OpenNoteDialog(val activity: Activity, val callback: (checkedId: Int) -> U
                 open_note_item_radio_button.apply {
                     text = note.title
                     isChecked = note.id == activity.config.currentNoteId
-                    id = note.id
+                    id = note.id!!
 
                     setOnClickListener {
                         callback(id)

app/src/main/kotlin/com/simplemobiletools/notes/pro/extensions/Context.kt

@@ -5,12 +5,16 @@ import android.content.ComponentName
 import android.content.Context
 import android.content.Intent
 import com.simplemobiletools.notes.pro.R
+import com.simplemobiletools.notes.pro.databases.NotesDatabase
 import com.simplemobiletools.notes.pro.helpers.*
+import com.simplemobiletools.notes.pro.interfaces.NotesDao
 
 val Context.config: Config get() = Config.newInstance(applicationContext)
 
 val Context.dbHelper: DBHelper get() = DBHelper.newInstance(applicationContext)
 
+val Context.notesDB: NotesDao get() = NotesDatabase.getInstance(applicationContext).NotesDao()
+
 fun Context.getTextSize() = when (config.fontSize) {
     FONT_SIZE_SMALL -> resources.getDimension(R.dimen.smaller_text_size)
     FONT_SIZE_LARGE -> resources.getDimension(R.dimen.big_text_size)

app/src/main/kotlin/com/simplemobiletools/notes/pro/helpers/DBHelper.kt

@@ -170,17 +170,17 @@ class DBHelper private constructor(private val mContext: Context) : SQLiteOpenHe
 
     fun updateNoteValue(note: Note) {
         val values = ContentValues().apply { put(COL_VALUE, note.value) }
-        updateNote(note.id, values)
+        updateNote(note.id!!, values)
     }
 
     fun updateNoteTitle(note: Note) {
         val values = ContentValues().apply { put(COL_TITLE, note.title) }
-        updateNote(note.id, values)
+        updateNote(note.id!!, values)
     }
 
     fun updateNotePath(note: Note) {
         val values = ContentValues().apply { put(COL_PATH, note.path) }
-        updateNote(note.id, values)
+        updateNote(note.id!!, values)
     }
 
     private fun updateNote(id: Int, values: ContentValues) {

app/src/main/kotlin/com/simplemobiletools/notes/pro/interfaces/NotesDao.kt

@@ -0,0 +1,19 @@
+package com.simplemobiletools.notes.pro.interfaces
+
+import androidx.room.Dao
+import androidx.room.Insert
+import androidx.room.OnConflictStrategy
+import androidx.room.Query
+import com.simplemobiletools.notes.pro.models.Note
+
+@Dao
+interface NotesDao {
+    @Query("SELECT * FROM notes")
+    fun getNotes(): List<Note>
+
+    @Query("SELECT * FROM notes WHERE id = :id")
+    fun getNoteWithId(id: Int): Note?
+
+    @Insert(onConflict = OnConflictStrategy.REPLACE)
+    fun insertOrUpdate(note: Note): Long
+}

app/src/main/kotlin/com/simplemobiletools/notes/pro/models/Note.kt

@@ -1,9 +1,20 @@
 package com.simplemobiletools.notes.pro.models
 
+import androidx.room.ColumnInfo
+import androidx.room.Entity
+import androidx.room.Index
+import androidx.room.PrimaryKey
 import java.io.File
 import java.io.FileNotFoundException
 
-data class Note(var id: Int, var title: String, var value: String, val type: Int, var path: String = "") {
+@Entity(tableName = "notes", indices = [(Index(value = ["id"], unique = true))])
+data class Note(
+        @PrimaryKey(autoGenerate = true) var id: Int?,
+        @ColumnInfo(name = "title") var title: String,
+        @ColumnInfo(name = "value") var value: String,
+        @ColumnInfo(name = "type") var type: Int,
+        @ColumnInfo(name = "path") var path: String = "") {
+
     fun getNoteStoredValue(): String? {
         return if (path.isNotEmpty()) {
             return try {

app/src/main/kotlin/com/simplemobiletools/notes/pro/objects/MyExecutor.kt

@@ -0,0 +1,7 @@
+package com.simplemobiletools.notes.pro.objects
+
+import java.util.concurrent.Executors
+
+object MyExecutor {
+    val myExecutor = Executors.newSingleThreadExecutor()
+}