Recycler view not updating with notifyDataSetChanged();

when I dismiss the dialog box, it does not refresh the activity underneath it with the new data. I need to manually refresh the activity or start a new activity (which looks hacky) for it to appear, I'm not sure why my recyclerViewAdapter.notifyDataSetChanged(); isn't working in the saveItem method.

package com.bawp.babyneeds; import android.app.AlertDialog; import android.content.Intent; import android.os.Bundle; import android.os.Handler; import android.support.design.widget.FloatingActionButton; import android.support.design.widget.Snackbar; import android.support.v7.app.AppCompatActivity; import android.support.v7.widget.LinearLayoutManager; import android.support.v7.widget.RecyclerView; import android.util.Log; import android.view.View; import android.widget.Button; import android.widget.EditText; import com.bawp.babyneeds.data.DatabaseHandlerDiary; import com.bawp.babyneeds.model.Diary; import com.bawp.babyneeds.ui.RecyclerViewAdapter; import java.util.ArrayList; import java.util.List; public class ListActivity extends AppCompatActivity { private static final String TAG = "ListActivity"; private RecyclerView recyclerView; private RecyclerViewAdapter recyclerViewAdapter; private List<Diary> diaryList; private DatabaseHandlerDiary databaseHandlerDiary; private FloatingActionButton fab; private AlertDialog.Builder builder; private AlertDialog alertDialog; private Button saveButton; private EditText diaryName; private EditText diaryDesc; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_list); recyclerView = findViewById(R.id.recyclerview); fab = findViewById(R.id.fab); databaseHandlerDiary = new DatabaseHandlerDiary(this); recyclerView.setHasFixedSize(true); recyclerView.setLayoutManager(new LinearLayoutManager(this)); diaryList = new ArrayList<>(); //Get items from db diaryList = databaseHandlerDiary.getAllDiaries(); for (Diary diary : diaryList) { Log.d(TAG, "onCreate: " + diary.getDiaryDesc()); } recyclerViewAdapter = new RecyclerViewAdapter(this, diaryList); recyclerView.setAdapter(recyclerViewAdapter); recyclerViewAdapter.notifyDataSetChanged(); fab.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { createPopDialog(); } }); } private void createPopDialog() { builder = new AlertDialog.Builder(this); View view = getLayoutInflater().inflate(R.layout.popup, null); diaryName = view.findViewById(R.id.edit_text_name_diary); diaryDesc = view.findViewById(R.id.edit_text_desc_diary); saveButton = view.findViewById(R.id.saveButton); builder.setView(view); alertDialog = builder.create(); alertDialog.show(); saveButton.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { if (!diaryName.getText().toString().isEmpty() && !diaryDesc.getText().toString().isEmpty()) { saveItem(v); //recyclerViewAdapter.notifyDataSetChanged(); }else { Snackbar.make(v, "Empty Fields not Allowed", Snackbar.LENGTH_SHORT) .show(); } } }); } private void saveItem(View view) { //Todo: save each baby diary to db final Diary diary = new Diary(); String newDiary = diaryName.getText().toString().trim(); String newDesc = diaryDesc.getText().toString().trim(); diary.setDiaryName(newDiary); diary.setDiaryDesc(newDesc); databaseHandlerDiary.addDiary(diary); recyclerViewAdapter.notifyDataSetChanged(); // <-------------------------this is not working Snackbar.make(view, "Diary Saved",Snackbar.LENGTH_SHORT) .show(); new Handler().postDelayed(new Runnable() { @Override public void run() { alertDialog.dismiss(); //Todo: move to next screen - details screen //startActivity(new Intent(ListActivity.this, ListActivity.class)); //finish(); } }, 1000); } } 

Thanks...

added DatabaseHandlerDiary class

package com.bawp.babyneeds.data; import android.content.ContentValues; import android.content.Context; import android.database.Cursor; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteOpenHelper; import com.bawp.babyneeds.model.Diary; import com.bawp.babyneeds.R; import com.bawp.babyneeds.util.Util; import java.text.DateFormat; import java.util.ArrayList; import java.util.Date; import java.util.List; public class DatabaseHandlerDiary extends SQLiteOpenHelper { public DatabaseHandlerDiary(Context context) { super(context, Util.DATABASE_NAME_DIARY, null, Util.DATA_BASE_VERSION_DIARY); } @Override public void onCreate(SQLiteDatabase db) { String CREATE_DIARY_TABLE = "CREATE TABLE " + Util.TABLE_NAME_DIARY + " (" + Util.KEY_ID_DIARY + " INTEGER PRIMARY KEY," + Util.KEY_NAME_DIARY + " TEXT," + Util.KEY_DESC_DIARY + " TEXT," + Util.KEY_DATE_ADDED_DIARY + ")"; db.execSQL(CREATE_DIARY_TABLE); } @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { String DROP_TABLE = String.valueOf(R.string.db_drop); db.execSQL(DROP_TABLE, new String[]{Util.DATABASE_NAME_DIARY}); //create new table onCreate(db); } //CRUD: create read update delete //add diary public void addDiary(Diary diary) { SQLiteDatabase db = this.getWritableDatabase(); ContentValues values = new ContentValues(); values.put(Util.KEY_NAME_DIARY, diary.getDiaryName()); values.put(Util.KEY_DESC_DIARY, diary.getDiaryDesc()); values.put(Util.KEY_DATE_ADDED_DIARY, diary.getDateDiaryAdded()); //^ insert to row db.insert(Util.TABLE_NAME_DIARY, null, values); db.close(); } //get diary public Diary getDiary(int id) { SQLiteDatabase db = this.getReadableDatabase(); Cursor cursor = db.query(Util.TABLE_NAME_DIARY, new String[]{ Util.KEY_NAME_DIARY, Util.KEY_DESC_DIARY, Util.KEY_DATE_ADDED_DIARY}, Util.KEY_ID_DIARY +"=?", new String[]{String.valueOf(id)}, null, null, null); if (cursor != null) { cursor.moveToFirst(); } Diary diary = new Diary(); diary.setDiaryId(Integer.parseInt(cursor.getString(0))); diary.setDiaryName(cursor.getString(1)); diary.setDiaryDesc(cursor.getString(2)); return diary; } //get all diaries public List<Diary> getAllDiaries() { SQLiteDatabase db = this.getReadableDatabase(); List<Diary> diaryList = new ArrayList<>(); Cursor cursor = db.query(Util.TABLE_NAME_DIARY, new String[]{Util.KEY_ID_DIARY, Util.KEY_NAME_DIARY, Util.KEY_DESC_DIARY, Util.KEY_DATE_ADDED_DIARY}, null, null, null, null, Util.KEY_DATE_ADDED_DIARY + " DESC"); if (cursor.moveToFirst()) { do { Diary diary = new Diary(); diary.setDiaryId(Integer.parseInt(cursor.getString(cursor.getColumnIndex(Util.KEY_ID_DIARY)))); diary.setDiaryName(cursor.getString(cursor.getColumnIndex(Util.KEY_NAME_DIARY))); diary.setDiaryDesc(cursor.getString(cursor.getColumnIndex(Util.KEY_DESC_DIARY))); //convert Timestamp to something readable DateFormat dateFormat = DateFormat.getDateInstance(); String formattedDate = dateFormat.format(new Date(cursor.getLong(cursor.getColumnIndex(Util.KEY_DATE_ADDED_DIARY))) .getTime()); // Feb 23, 2020 diary.setDateDiaryAdded(formattedDate); //Add to arraylist diaryList.add(diary); } while (cursor.moveToNext()); } return diaryList; } public int updateItem(Diary diary) { SQLiteDatabase db = this.getWritableDatabase(); ContentValues values = new ContentValues(); values.put(Util.KEY_NAME_DIARY, diary.getDiaryName()); values.put(Util.KEY_DESC_DIARY, diary.getDiaryDesc()); values.put(Util.KEY_DATE_ADDED_DIARY, java.lang.System.currentTimeMillis());//timestamp of the system //update row return db.update(Util.TABLE_NAME_DIARY, values, Util.KEY_ID_DIARY + "=?", new String[]{String.valueOf(diary.getDiaryId())}); } //Todo: Add Delete Item public void deleteItem(int id) { SQLiteDatabase db = this.getWritableDatabase(); db.delete(Util.TABLE_NAME_DIARY, Util.KEY_ID_DIARY + "=?", new String[]{String.valueOf(id)}); //close db.close(); } //Todo: getItemCount public int getItemsCount() { String countQuery = "SELECT * FROM " + Util.TABLE_NAME_DIARY; SQLiteDatabase db = this.getReadableDatabase(); Cursor cursor = db.rawQuery(countQuery, null); return cursor.getCount(); } }