Why the note pages can't show up and can't sync

  • My purpose: I am using Realm as a database and I am making a note app .I suppose note page can be saved and there is new info (a new column) in the mainActivity .However , after clicking the Save button in the action bar . These can't work but no error is made .
    What files I have? 1.RealmBasicConfig 2.AddSaveNotesActivity 3.NotesAdapter 4.notes_rv_layout (for the pre-set first note view) 5.MainActivity( The first page in the app )

    What solutions I want : why notes_rv_layout does not work , and the notes content can not be synced It should be the problem of the mainActivity ( adapter!!.notifyDataSetChanged - can't work ?)

    The codes of MainActivity:

    class Main2Activity : AppCompatActivity() {
        private lateinit var notesList:ArrayList<BasicInfoConfig>
        private lateinit var realm: Realm
        private lateinit var appBarConfiguration: AppBarConfiguration
        override fun onCreate(savedInstanceState: Bundle?) {
            val toolbar: Toolbar = findViewById(R.id.toolbar)
            val drawerLayout: DrawerLayout = findViewById(R.id.drawer_layout)
            val navView: NavigationView = findViewById(R.id.nav_view)
            val navController = findNavController(R.id.nav_host_fragment)
            // Passing each menu ID as a set of Ids because each
            // menu should be considered as top level destinations.
            appBarConfiguration = AppBarConfiguration(setOf(
                    R.id.nav_home, R.id.nav_gallery, R.id.nav_slideshow), drawerLayout)
            setupActionBarWithNavController(navController, appBarConfiguration)
            //custom init views
            realm  = Realm.getDefaultInstance()
            //set onclicklistener
            notesRV.layoutManager = LinearLayoutManager(this)
        private fun getAllNotes() {  //yellow : used
            notesList = ArrayList()
            val  results:RealmResults<BasicInfoConfig> = realm.where<BasicInfoConfig>(BasicInfoConfig::class.java).findAll()
            notesRV.adapter = NotesAdapter(this,results)
            notesRV.adapter!!.notifyDataSetChanged()   // to update   // bec  I deleted the way it saved // none info can be read
        override fun onNewIntent(intent: Intent) {
        override fun onCreateOptionsMenu(menu: Menu): Boolean {
            // Inflate the menu; this adds items to the action bar if it is present.
            menuInflater.inflate(R.menu.main2, menu)
            // Associate searchable configuration with the SearchView
            // Associate searchable configuration with the SearchView
            val searchManager = getSystemService(Context.SEARCH_SERVICE) as SearchManager
            (menu.findItem(R.id.search).actionView as SearchView).apply {
            return true
        override fun onBackPressed() {
        override fun onSupportNavigateUp(): Boolean {
            val navController = findNavController(R.id.nav_host_fragment)
            return navController.navigateUp(appBarConfiguration) || super.onSupportNavigateUp()
        private fun handleIntent(intent: Intent) {
            if (Intent.ACTION_SEARCH == intent.action) {
             val query = intent.getStringExtra(SearchManager.QUERY)
                //use the query to search your data somehow

    The codes of NotesAdapterView

    class NotesAdapter (private val context : Context? , private  val notesList : RealmResults<BasicInfoConfig>)
        : RecyclerView.Adapter<RecyclerView.ViewHolder>(){
        override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
            val v = LayoutInflater.from(parent.context).inflate(R.layout.notes_rv_layout, parent,false)
            return ViewHolder(v)
        override fun getItemCount(): Int {
            return notesList.size
        override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {
                holder.itemView.notes_title.text = notesList[position]!!.title
                holder.itemView.notes_body.text = notesList[position]!!.description
        class  ViewHolder(v:View?):RecyclerView.ViewHolder(v!!) {
            val Ada_title = itemView.findViewById<TextView>(R.id.notes_title)
            val Ada_date = itemView.findViewById<TextView>(R.id.notes_timeStamp)
    The codes of RealmBasicConfig:
    package com.example.notepad_free
    import io.realm.RealmObject
    import io.realm.annotations.PrimaryKey
    open class BasicInfoConfig(
    //connecting  basic info to Realm
    var id:Int ?= null,
    var title:String?=null,
    var description:String?=null

    Please tell me if more codes are needed , feel grateful if you help!

    android-recyclerview realm android-studio-3.0

  • is this website forcing me to post the pic , wtf? There 's only a little space for me to see my editing .

  • Wish I could help @locus-jim

    but I am not great at android.