Improved code readability and maintainability

app/src/main/java/com/sbeve/jada/fragments/main/MainFragment.kt

@@ -31,16 +31,23 @@ class MainFragment : Fragment(R.layout.fragment_main), RecentQueriesAdapter.OnCl
     private val mainActivityContext: MainActivity by lazy {
         activity as MainActivity
     }
+
+    //animation to be played when a fragment transaction happens from this activity a pop action transaction to this activity happens so the fragment
+    //doesn't disappear from the background
     private val stayInPlaceAnimation: Animation? by lazy {
         val anim: Animation = AlphaAnimation(1.0F, 1.0F)
         anim.duration = 150
         anim
     }
     private val viewModel: MainViewModel by viewModels()
     private lateinit var fragmentMainBinding: FragmentMainBinding
+
+    //getting the saved language setting's value through a custom getter
     private val savedLanguageIndex: Int
         get() = mainActivityContext.applicationPreferences
             .getInt(getString(R.string.language_setting_key), 0)
+
+    //adapter with empty list as the list will be provided when the database emits information
     private val adapter by lazy {
         RecentQueriesAdapter(emptyList(), this)
     }
@@ -49,7 +56,6 @@ class MainFragment : Fragment(R.layout.fragment_main), RecentQueriesAdapter.OnCl
         super.onViewCreated(view, savedInstanceState)
 
         fragmentMainBinding = FragmentMainBinding.bind(view)
-        updateRecyclerView()
         fragmentMainBinding.changeLanguageGearIcon.setOnClickListener {
             createChangeLanguageDialog().show()
         }
@@ -60,13 +66,16 @@ class MainFragment : Fragment(R.layout.fragment_main), RecentQueriesAdapter.OnCl
         fragmentMainBinding.queriesRecyclerView.setHasFixedSize(true)
         fragmentMainBinding.queriesRecyclerView.adapter = adapter
 
+        //set up an observer to update the recycler view whenever the database is updated
+        updateRecyclerView()
+
         //set the text view's text to show whichever language is selected and update the text whenever the setting is changed
         fragmentMainBinding.currentLanguage.text = RetrofitInit.supportedLanguages.first[savedLanguageIndex]
         mainActivityContext.applicationPreferences.registerOnSharedPreferenceChangeListener(this)
 
         fragmentMainBinding.searchView.setOnQueryTextListener(object : SearchView.OnQueryTextListener {
             override fun onQueryTextSubmit(query: String): Boolean {
-                viewModel.addQuery(query, savedLanguageIndex)
+                viewModel.addQuery(RecentQuery(query, savedLanguageIndex))
                 navController.navigate(MainFragmentDirections.actionMainFragmentToResultFragment(query, savedLanguageIndex))
                 hideSoftKeyboard()
                 return true
@@ -79,6 +88,7 @@ class MainFragment : Fragment(R.layout.fragment_main), RecentQueriesAdapter.OnCl
     //play an empty animation to keep the fragment from disappearing from the background when the enter animation for other fragments is playing
     override fun onCreateAnimation(transit: Int, enter: Boolean, nextAnim: Int) = stayInPlaceAnimation
 
+    //change language dialog to change the language to be used by the dictionary
     private fun createChangeLanguageDialog() =
         MaterialAlertDialogBuilder(mainActivityContext)
             .setTitle(getString(R.string.choose_a_language))
@@ -113,15 +123,12 @@ class MainFragment : Fragment(R.layout.fragment_main), RecentQueriesAdapter.OnCl
         }
     }
 
-    override fun onItemClick(position: Int) {
-        val queryText = viewModel.allQueries.value!![position].queryText
-        val queryLanguage = viewModel.allQueries.value!![position].queryLanguage
-        navController.navigate(MainFragmentDirections.actionMainFragmentToResultFragment(queryText, queryLanguage))
+    override fun onItemClick(query: String, queryLanguageIndex: Int) {
+        navController.navigate(MainFragmentDirections.actionMainFragmentToResultFragment(query, queryLanguageIndex))
     }
 
     override fun onDeleteButtonClick(query: String, queryLanguageIndex: Int) {
-        val recentQuery = RecentQuery(query, queryLanguageIndex)
-        viewModel.deleteQuery(recentQuery)
+        viewModel.deleteQuery(RecentQuery(query, queryLanguageIndex))
     }
 
     override fun onSharedPreferenceChanged(sharedPreferences: SharedPreferences?, key: String?) {

app/src/main/java/com/sbeve/jada/fragments/main/MainViewModel.kt

@@ -37,9 +37,8 @@ class MainViewModel : ViewModel() {
     }
 
     //add a query whenever a new word is searched
-    fun addQuery(query: String, languageIndex: Int) {
+    fun addQuery(recentQuery: RecentQuery) {
         viewModelScope.launch(IO) {
-            val recentQuery = RecentQuery(query, languageIndex, System.currentTimeMillis())
             databaseDao.addQuery(recentQuery)
         }
     }

app/src/main/java/com/sbeve/jada/recyclerview_utils/RecentQueriesAdapter.kt

@@ -12,42 +12,44 @@ import java.util.*
 import kotlin.properties.Delegates
 
 class RecentQueriesAdapter(var dataSet: List<RecentQuery>, private val onClickListener: OnClickListener) :
-    RecyclerView.Adapter<RecentQueriesAdapter.ViewHolder>() {
+    RecyclerView.Adapter<RecentQueriesAdapter.RecentQueriesViewHolder>() {
 
-    class ViewHolder(myItemView: QueryLayoutBinding, private val onClickListener: OnClickListener) :
+    class RecentQueriesViewHolder(myItemView: QueryLayoutBinding, private val onClickListener: OnClickListener) :
         RecyclerView.ViewHolder(myItemView.root) {
+
         private val queryText = myItemView.queryText
+        private lateinit var queryTextValue: String
         private val time = myItemView.time
         private val queryLanguage = myItemView.language
         private var queryLanguageValue by Delegates.notNull<Int>()
 
         fun setLanguageText(languageValue: Int) {
             queryLanguageValue = languageValue
             queryLanguage.text = RetrofitInit.supportedLanguages.first[languageValue]
-
         }
 
         fun setQueryText(queryValue: String) {
+            queryTextValue = queryValue
             queryText.text = HtmlCompat.fromHtml(queryValue, HtmlCompat.FROM_HTML_MODE_LEGACY)
         }
 
         fun setTimeText(timeValue: Long) {
             time.text = SimpleDateFormat("HH:mm, dd MMM, yyyy", Locale.getDefault()).format(timeValue)
         }
 
+        //setting on click listeners for each item and the delete button in each item
         init {
-            myItemView.root.setOnClickListener { onClickListener.onItemClick(adapterPosition) }
+            myItemView.root.setOnClickListener { onClickListener.onItemClick(queryTextValue, queryLanguageValue) }
             myItemView.deleteButton.setOnClickListener { onClickListener.onDeleteButtonClick(queryText.text.toString(), queryLanguageValue) }
         }
-
     }
 
-    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
+    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecentQueriesViewHolder {
         val binding = QueryLayoutBinding.inflate(LayoutInflater.from(parent.context), parent, false)
-        return ViewHolder(binding, onClickListener)
+        return RecentQueriesViewHolder(binding, onClickListener)
     }
 
-    override fun onBindViewHolder(holder: ViewHolder, position: Int) {
+    override fun onBindViewHolder(holder: RecentQueriesViewHolder, position: Int) {
         val currentItem = dataSet[position]
         holder.setQueryText(currentItem.queryText)
         holder.setTimeText(currentItem.timeDate)
@@ -56,8 +58,9 @@ class RecentQueriesAdapter(var dataSet: List<RecentQuery>, private val onClickLi
 
     override fun getItemCount() = dataSet.size
 
+    //custom interface to be implemented by the main activity to set up onClickListeners
     interface OnClickListener {
-        fun onItemClick(position: Int)
+        fun onItemClick(query: String, queryLanguageIndex: Int)
         fun onDeleteButtonClick(query: String, queryLanguageIndex: Int)
     }
 }