Dirty selection implementation

app/build.gradle

@@ -44,7 +44,7 @@ dependencies {
     implementation 'com.google.firebase:firebase-auth:16.2.1'
     implementation 'com.firebase:firebase-client-android:2.3.1'
     implementation 'com.google.firebase:firebase-firestore:18.2.0'
-    implementation 'com.crashlytics.sdk.android:crashlytics:2.9.9'
+//    implementation 'com.crashlytics.sdk.android:crashlytics:2.9.9'
     implementation 'androidx.recyclerview:recyclerview-selection:1.0.0'
 
     testImplementation 'junit:junit:4.12'

app/src/main/java/com/paktalin/vocabularynotebook/ui/MyItemDetailsLookup.kt

+package com.paktalin.vocabularynotebook.ui
+
+import android.view.MotionEvent
+import androidx.recyclerview.selection.ItemDetailsLookup
+import androidx.recyclerview.widget.RecyclerView
+
+class MyItemDetailsLookup(private val recyclerView: RecyclerView) :
+        ItemDetailsLookup<Long>() {
+    override fun getItemDetails(event: MotionEvent): ItemDetails<Long>? {
+        val view = recyclerView.findChildViewUnder(event.x, event.y)
+        if (view != null) {
+            return (recyclerView.getChildViewHolder(view) as ViewHolder)
+                    .getItemDetails()
+        }
+        return null
+    }
+}
\ No newline at end of file

app/src/main/java/com/paktalin/vocabularynotebook/ui/ViewHolder.kt

 package com.paktalin.vocabularynotebook.ui
 
 import android.graphics.Color
-import androidx.recyclerview.widget.RecyclerView
 import android.view.View
 import android.widget.LinearLayout
 import android.widget.TextView
+import androidx.recyclerview.selection.ItemDetailsLookup
+import androidx.recyclerview.widget.RecyclerView
 import com.paktalin.vocabularynotebook.firestoreitems.WordPojo
-import com.paktalin.vocabularynotebook.ui.activities.MainActivity
 import com.paktalin.vocabularynotebook.utils.Log
 import kotlinx.android.synthetic.main.word_item.view.*
 
@@ -20,10 +20,17 @@ class ViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView), View.OnCli
     private val tvTranslation: TextView = itemView.translation
     val layout: LinearLayout = itemView.layout
 
-    fun bind(wordPojo: WordPojo, position: Int, showPopupMenu: (View, Int) -> Unit) {
+    fun bind(wordPojo: WordPojo, position: Int, isActivated: Boolean, showPopupMenu: (View, Int) -> Unit) {
         tvWord.text = wordPojo.word
         tvTranslation.text = wordPojo.translation
-        itemView.setOnClickListener { showPopupMenu(itemView, position) }
+//        itemView.setOnClickListener { showPopupMenu(itemView, position) }
+        itemView.isActivated = isActivated
+    }
+
+    fun getItemDetails(): ItemDetailsLookup.ItemDetails<Long> =
+            object : ItemDetailsLookup.ItemDetails<Long>() {
+                override fun getPosition(): Int = adapterPosition
+                override fun getSelectionKey(): Long? = itemId
             }
 
     companion object {

app/src/main/java/com/paktalin/vocabularynotebook/ui/VocabularyAdapter.kt

@@ -3,14 +3,17 @@ package com.paktalin.vocabularynotebook.ui
 import android.annotation.SuppressLint
 import android.os.Build
 import android.os.Bundle
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
 import androidx.appcompat.widget.PopupMenu
+import androidx.recyclerview.selection.SelectionTracker
 import androidx.recyclerview.widget.RecyclerView
-import android.view.*
 import com.paktalin.vocabularynotebook.OnQueryTextListener
 import com.paktalin.vocabularynotebook.R
 import com.paktalin.vocabularynotebook.firestoreitems.WordPojo
-import com.paktalin.vocabularynotebook.ui.fragments.EditWordFragment
 import com.paktalin.vocabularynotebook.ui.activities.MainActivity
+import com.paktalin.vocabularynotebook.ui.fragments.EditWordFragment
 import com.paktalin.vocabularynotebook.utils.Log
 import com.paktalin.vocabularynotebook.utils.addFragment
 import com.paktalin.vocabularynotebook.utils.shortToast
@@ -22,6 +25,13 @@ class VocabularyAdapter(private val vocabulary: VocabSet, private val mainActivi
 
     private lateinit var recyclerView: RecyclerView
     private lateinit var viewHolder: ViewHolder
+    var tracker: SelectionTracker<Long>? = null
+
+    init {
+        setHasStableIds(true)
+    }
+
+    override fun getItemId(position: Int): Long = position.toLong()
 
     var sort: Sort = Sort.BY_TIME
     set(value) {
@@ -46,7 +56,9 @@ class VocabularyAdapter(private val vocabulary: VocabSet, private val mainActivi
 
     override fun onBindViewHolder(viewHolder: ViewHolder, position: Int) {
         val wordItem = vocabulary.displayedAt(position)
-        viewHolder.bind(wordItem, position) { view, p -> showPopupMenu(view, p)}
+        tracker?.let {
+            viewHolder.bind(wordItem, position, it.isSelected(position.toLong())) { view, p -> showPopupMenu(view, p) }
+        }
         this.viewHolder = viewHolder
         //todo set click listener to menu
     }

app/src/main/java/com/paktalin/vocabularynotebook/ui/activities/MainActivity.kt

@@ -2,14 +2,19 @@ package com.paktalin.vocabularynotebook.ui.activities
 
 import android.app.Activity
 import android.os.Bundle
-import androidx.appcompat.app.AppCompatActivity
-import androidx.appcompat.widget.SearchView
 import android.view.Menu
 import android.view.MenuItem
 import android.view.View
 import android.view.WindowManager
 import android.view.inputmethod.InputMethodManager
+import androidx.appcompat.app.AppCompatActivity
+import androidx.appcompat.widget.SearchView
+import androidx.recyclerview.selection.SelectionPredicates
+import androidx.recyclerview.selection.SelectionTracker
+import androidx.recyclerview.selection.StableIdKeyProvider
+import androidx.recyclerview.selection.StorageStrategy
 import com.paktalin.vocabularynotebook.R
+import com.paktalin.vocabularynotebook.ui.MyItemDetailsLookup
 import com.paktalin.vocabularynotebook.ui.VocabularyAdapter
 import com.paktalin.vocabularynotebook.ui.views.LockableLayoutManager
 import com.paktalin.vocabularynotebook.utils.*
@@ -17,12 +22,12 @@ import com.paktalin.vocabularynotebook.vocabulary.Sort
 import com.paktalin.vocabularynotebook.vocabulary.VocabSet
 import kotlinx.android.synthetic.main.activity_main.*
 import kotlinx.android.synthetic.main.content_main.*
-import java.lang.Exception
 
 class MainActivity : AppCompatActivity() {
 
     lateinit var searchView: SearchView
     lateinit var vocabularyAdapter: VocabularyAdapter
+    private var tracker: SelectionTracker<Long>? = null
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
@@ -84,13 +89,23 @@ class MainActivity : AppCompatActivity() {
     private fun setUpVocabularyAdapter() {
         addProgressBar(supportFragmentManager, R.id.container_main)
         FirestoreManager().extractVocabularyId({
-//                    recyclerView.adapter = VocabularyAdapter(BasicVocabulary(), this@MainActivity)
                     recyclerView.layoutManager = LockableLayoutManager(this@MainActivity)
                     FirestoreManager().extractVocabulary { querySnapshot ->
                         run {
                             if (querySnapshot != null && !querySnapshot.isEmpty) {
                                 vocabularyAdapter = VocabularyAdapter(VocabSet.createFromSnapshot(querySnapshot), this@MainActivity)
                                 recyclerView.adapter = vocabularyAdapter
+                                tracker = SelectionTracker.Builder<Long>(
+                                        "mySelection",
+                                        recyclerView,
+                                        StableIdKeyProvider(recyclerView),
+                                        MyItemDetailsLookup(recyclerView),
+                                        StorageStrategy.createLongStorage()
+                                ).withSelectionPredicate(
+                                        SelectionPredicates.createSelectAnything()
+                                ).build()
+                                (recyclerView.adapter as VocabularyAdapter).tracker = tracker
+
                             }
                             else showToastNoWords()
                         }

app/src/main/res/drawable/selector.xml

+<?xml version="1.0" encoding="utf-8"?>
+<selector xmlns:android="http://schemas.android.com/apk/res/android">
+    <item android:drawable="@android:color/holo_blue_light" android:state_activated="true" />
+    <item android:drawable="@android:color/white" />
+</selector>
\ No newline at end of file

app/src/main/res/layout/word_item.xml

@@ -33,6 +33,7 @@
         android:paddingEnd="16dp"
         android:paddingRight="16dp"
         android:paddingBottom="8dp"
+        android:background="@drawable/selector"
         app:layout_constraintTop_toTopOf="parent">
 
         <TextView