lets just recreate the viewpager at new note, rename, delete

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

@@ -33,14 +33,7 @@ class MainActivity : SimpleActivity(), ViewPager.OnPageChangeListener {
         setContentView(R.layout.activity_main)
 
         mDb = DBHelper.newInstance(applicationContext)
-        mNotes = mDb.getNotes()
+        initViewPager()
-        mCurrentNote = mNotes[0]
-
-        mAdapter = NotesPagerAdapter(supportFragmentManager, mNotes)
-        view_pager.apply {
-            adapter = mAdapter
-            addOnPageChangeListener(this@MainActivity)
-        }
 
         notes_fab.setOnClickListener { displayNewNoteDialog() }
         notes_fab.viewTreeObserver.addOnGlobalLayoutListener {
@@ -49,6 +42,18 @@ class MainActivity : SimpleActivity(), ViewPager.OnPageChangeListener {
         }
     }
 
+    fun initViewPager() {
+        mNotes = mDb.getNotes().sortedBy(Note::title)
+        mCurrentNote = mNotes[0]
+
+        mAdapter = NotesPagerAdapter(supportFragmentManager, mNotes)
+        view_pager.apply {
+            adapter = mAdapter
+            currentItem = 0
+            addOnPageChangeListener(this@MainActivity)
+        }
+    }
+
     override fun onResume() {
         super.onResume()
         invalidateOptionsMenu()
@@ -118,6 +123,7 @@ class MainActivity : SimpleActivity(), ViewPager.OnPageChangeListener {
         RenameNoteDialog(this, mDb, mCurrentNote) {
             mCurrentNote = it
             current_note_title.text = it.title
+            initViewPager()
         }
     }
 
@@ -132,6 +138,7 @@ class MainActivity : SimpleActivity(), ViewPager.OnPageChangeListener {
             updateSelectedNote(id)
             mNotes = mDb.getNotes()
             invalidateOptionsMenu()
+            initViewPager()
         }
     }
 
@@ -153,6 +160,7 @@ class MainActivity : SimpleActivity(), ViewPager.OnPageChangeListener {
         updateSelectedNote(firstNoteId)
         config.widgetNoteId = firstNoteId
         invalidateOptionsMenu()
+        initViewPager()
     }
 
     private fun displayOpenNoteDialog() {