convert dbhelper to kotlin

app/src/main/java/com/simplemobiletools/notes/activities/MainActivity.java

@@ -43,7 +43,7 @@ public class MainActivity extends SimpleActivity implements OpenNoteDialog.OpenN
         setContentView(R.layout.activity_main);
         ButterKnife.bind(this);
 
-        mDb = DBHelper.newInstance(getApplicationContext());
+        mDb = DBHelper.Companion.newInstance(getApplicationContext());
         mNotes = mDb.getNotes();
         updateSelectedNote(getConfig().getCurrentNoteId());
 }

app/src/main/java/com/simplemobiletools/notes/databases/DBHelper.java

@@ -1,141 +0,0 @@
-package com.simplemobiletools.notes.databases;
-
-import android.content.ContentValues;
-import android.content.Context;
-import android.content.SharedPreferences;
-import android.database.Cursor;
-import android.database.sqlite.SQLiteDatabase;
-import android.database.sqlite.SQLiteOpenHelper;
-
-import com.simplemobiletools.notes.Constants;
-import com.simplemobiletools.notes.models.Note;
-
-import java.util.ArrayList;
-import java.util.List;
-
-public class DBHelper extends SQLiteOpenHelper {
-    private static final String DB_NAME = "notes.db";
-    private static final int DB_VERSION = 1;
-    private static final String TABLE_NAME = "notes";
-    private static final String NOTE = "General note";
-
-    private static final String COL_ID = "id";
-    private static final String COL_TITLE = "title";
-    private static final String COL_VALUE = "value";
-
-    private Context mContext;
-    private SQLiteDatabase mDb;
-
-    public static DBHelper newInstance(Context context) {
-        return new DBHelper(context);
-    }
-
-    private DBHelper(Context context) {
-        super(context, DB_NAME, null, DB_VERSION);
-        mContext = context;
-        mDb = getWritableDatabase();
-    }
-
-    @Override
-    public void onCreate(SQLiteDatabase db) {
-        db.execSQL("CREATE TABLE " + TABLE_NAME + " (" +
-                COL_ID + " INTEGER PRIMARY KEY, " +
-                COL_TITLE + " TEXT UNIQUE, " +
-                COL_VALUE + " TEXT" +
-                ")"
-        );
-
-        insertFirstNote(db);
-    }
-
-    @Override
-    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
-
-    }
-
-    private void insertFirstNote(SQLiteDatabase db) {
-        final SharedPreferences prefs = mContext.getSharedPreferences(Constants.PREFS_KEY, Context.MODE_PRIVATE);
-        final String text = prefs.getString(Constants.TEXT, "");
-        final Note note = new Note(1, NOTE, text);
-        insertNote(note, db);
-    }
-
-    private void insertNote(Note note, SQLiteDatabase db) {
-        final ContentValues values = fillContentValues(note);
-        db.insert(TABLE_NAME, null, values);
-    }
-
-    public int insertNote(Note note) {
-        final ContentValues values = fillContentValues(note);
-        return (int) mDb.insert(TABLE_NAME, null, values);
-    }
-
-    private ContentValues fillContentValues(Note note) {
-        final ContentValues values = new ContentValues();
-        values.put(COL_TITLE, note.getTitle());
-        values.put(COL_VALUE, note.getValue());
-        return values;
-    }
-
-    public void deleteNote(int id) {
-        mDb.delete(TABLE_NAME, COL_ID + " = " + id, null);
-    }
-
-    public boolean doesTitleExist(String title) {
-        final String cols[] = {COL_ID};
-        final String selection = COL_TITLE + " = ?";
-        final String selectionArgs[] = {title};
-        final Cursor cursor = mDb.query(TABLE_NAME, cols, selection, selectionArgs, null, null, null);
-
-        if (cursor == null)
-            return false;
-
-        final int cnt = cursor.getCount();
-        cursor.close();
-        return cnt == 1;
-    }
-
-    public List<Note> getNotes() {
-        final List<Note> notes = new ArrayList<>();
-        final String cols[] = {COL_ID, COL_TITLE, COL_VALUE};
-        final Cursor cursor = mDb.query(TABLE_NAME, cols, null, null, null, null, COL_TITLE + " COLLATE NOCASE ASC");
-        if (cursor != null) {
-            if (cursor.moveToFirst()) {
-                do {
-                    final int id = cursor.getInt(cursor.getColumnIndex(COL_ID));
-                    final String title = cursor.getString(cursor.getColumnIndex(COL_TITLE));
-                    final String value = cursor.getString(cursor.getColumnIndex(COL_VALUE));
-                    final Note note = new Note(id, title, value);
-                    notes.add(note);
-                } while (cursor.moveToNext());
-            }
-            cursor.close();
-        }
-
-        return notes;
-    }
-
-    public Note getNote(int id) {
-        final String cols[] = {COL_TITLE, COL_VALUE};
-        final String selection = COL_ID + " = ?";
-        final String selectionArgs[] = {String.valueOf(id)};
-        final Cursor cursor = mDb.query(TABLE_NAME, cols, selection, selectionArgs, null, null, null);
-        Note note = null;
-        if (cursor != null) {
-            if (cursor.moveToFirst()) {
-                final String title = cursor.getString(cursor.getColumnIndex(COL_TITLE));
-                final String value = cursor.getString(cursor.getColumnIndex(COL_VALUE));
-                note = new Note(id, title, value);
-            }
-            cursor.close();
-        }
-        return note;
-    }
-
-    public void updateNote(Note note) {
-        final ContentValues values = fillContentValues(note);
-        final String selection = COL_ID + " = ?";
-        final String selectionArgs[] = new String[]{String.valueOf(note.getId())};
-        mDb.update(TABLE_NAME, values, selection, selectionArgs);
-    }
-}

app/src/main/kotlin/com/simplemobiletools/notes/Config.kt

@@ -7,9 +7,7 @@ class Config(context: Context) {
     private val mPrefs: SharedPreferences
 
     companion object {
-        fun newInstance(context: Context): Config {
+        fun newInstance(context: Context) = Config(context)
-            return Config(context)
-        }
     }
 
     init {

app/src/main/kotlin/com/simplemobiletools/notes/databases/DBHelper.kt

@@ -0,0 +1,126 @@
+package com.simplemobiletools.notes.databases
+
+import android.content.ContentValues
+import android.content.Context
+import android.database.Cursor
+import android.database.sqlite.SQLiteDatabase
+import android.database.sqlite.SQLiteOpenHelper
+import com.simplemobiletools.notes.Constants
+import com.simplemobiletools.notes.models.Note
+import java.util.*
+
+class DBHelper private constructor(private val mContext: Context) : SQLiteOpenHelper(mContext, DBHelper.DB_NAME, null, DBHelper.DB_VERSION) {
+    private val mDb: SQLiteDatabase
+
+    companion object {
+        private val DB_NAME = "notes.db"
+        private val DB_VERSION = 1
+        private val TABLE_NAME = "notes"
+        private val NOTE = "General note"
+
+        private val COL_ID = "id"
+        private val COL_TITLE = "title"
+        private val COL_VALUE = "value"
+
+        fun newInstance(context: Context) = DBHelper(context)
+    }
+
+    init {
+        mDb = writableDatabase
+    }
+
+    override fun onCreate(db: SQLiteDatabase) {
+        db.execSQL("CREATE TABLE $TABLE_NAME ($COL_ID INTEGER PRIMARY KEY, $COL_TITLE TEXT UNIQUE, $COL_VALUE TEXT)")
+        insertFirstNote(db)
+    }
+
+    override fun onUpgrade(db: SQLiteDatabase, oldVersion: Int, newVersion: Int) {
+
+    }
+
+    private fun insertFirstNote(db: SQLiteDatabase) {
+        val prefs = mContext.getSharedPreferences(Constants.PREFS_KEY, Context.MODE_PRIVATE)
+        val text = prefs.getString(Constants.TEXT, "")
+        val note = Note(1, NOTE, text)
+        insertNote(note, db)
+    }
+
+    private fun insertNote(note: Note, db: SQLiteDatabase) {
+        val values = fillContentValues(note)
+        db.insert(TABLE_NAME, null, values)
+    }
+
+    fun insertNote(note: Note): Int {
+        val values = fillContentValues(note)
+        return mDb.insert(TABLE_NAME, null, values).toInt()
+    }
+
+    private fun fillContentValues(note: Note): ContentValues {
+        return ContentValues().apply {
+            put(COL_TITLE, note.title)
+            put(COL_VALUE, note.value)
+        }
+    }
+
+    fun deleteNote(id: Int) {
+        mDb.delete(TABLE_NAME, COL_ID + " = " + id, null)
+    }
+
+    fun doesTitleExist(title: String): Boolean {
+        val cols = arrayOf(COL_ID)
+        val selection = COL_TITLE + " = ?"
+        val selectionArgs = arrayOf(title)
+        val cursor = mDb.query(TABLE_NAME, cols, selection, selectionArgs, null, null, null) ?: return false
+        val cnt = cursor.count
+        cursor.close()
+        return cnt == 1
+    }
+
+    fun getNotes(): List<Note> {
+        val notes = ArrayList<Note>()
+        val cols = arrayOf(COL_ID, COL_TITLE, COL_VALUE)
+        var cursor: Cursor? = null
+        try {
+            cursor = mDb.query(TABLE_NAME, cols, null, null, null, null, "$COL_TITLE COLLATE NOCASE ASC")
+            if (cursor != null && cursor.moveToFirst()) {
+                do {
+                    val id = cursor.getInt(cursor.getColumnIndex(COL_ID))
+                    val title = cursor.getString(cursor.getColumnIndex(COL_TITLE))
+                    val value = cursor.getString(cursor.getColumnIndex(COL_VALUE))
+                    val note = Note(id, title, value)
+                    notes.add(note)
+                } while (cursor.moveToNext())
+            }
+        } finally {
+            cursor?.close()
+        }
+
+        return notes
+    }
+
+    fun getNote(id: Int): Note? {
+        val cols = arrayOf(COL_TITLE, COL_VALUE)
+        val selection = "$COL_ID = ?"
+        val selectionArgs = arrayOf(id.toString())
+        var note: Note? = null
+        var cursor: Cursor? = null
+        try {
+            cursor = mDb.query(TABLE_NAME, cols, selection, selectionArgs, null, null, null)
+            if (cursor != null && cursor.moveToFirst()) {
+                val title = cursor.getString(cursor.getColumnIndex(COL_TITLE))
+                val value = cursor.getString(cursor.getColumnIndex(COL_VALUE))
+                note = Note(id, title, value)
+            }
+        } finally {
+            cursor?.close()
+        }
+        return note
+    }
+
+    fun updateNote(note: Note) {
+        val values = fillContentValues(note)
+        val selection = COL_ID + " = ?"
+        val selectionArgs = arrayOf(note.id.toString())
+        mDb.update(TABLE_NAME, values, selection, selectionArgs)
+    }
+}

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

@@ -17,7 +17,7 @@ class OpenNoteDialog(val activity: Activity) : RadioGroup.OnCheckedChangeListene
         val view = activity.layoutInflater.inflate(R.layout.dialog_radio_group, null) as RadioGroup
         view.setOnCheckedChangeListener(this)
 
-        val notes = DBHelper.newInstance(activity).notes
+        val notes = DBHelper.newInstance(activity).getNotes()
         notes.forEach {
             val radioButton = activity.layoutInflater.inflate(R.layout.radio_button, null) as RadioButton
             radioButton.apply {

app/src/main/kotlin/com/simplemobiletools/notes/dialogs/WidgetNoteDialog.kt

@@ -19,7 +19,7 @@ class WidgetNoteDialog(val activity: Activity) : RadioGroup.OnCheckedChangeListe
         view.setOnCheckedChangeListener(this)
 
         val db = DBHelper.newInstance(activity)
-        val notes = db.notes
+        val notes = db.getNotes()
         notes.forEach {
             val radioButton = activity.layoutInflater.inflate(R.layout.radio_button, null) as RadioButton
             radioButton.apply {