Comments and feedback

app/src/main/java/com/example/idletapperversion2/MainActivity.kt

@@ -12,12 +12,11 @@ class MainActivity : AppCompatActivity() {
 
     companion object {
         const val STATE_TAPS = "tapCount"
-        const val STATE_TAPPOW = "tapPower"
+        const val STATE_TAP_POWER = "tapPower" //Preferred
         const val STATE_IDLEPOW = "idlePower"
         const val STATE_UPGRADES = "upgrades"
     }
-
-    val TAG = "mainActivity"
+//  You missed removing this tag with your Log statements, I would guess. It surfaced in a warning.
 
     private var tapCount = 0
     private var tapPower = 1 //amount tapCount increments when tap button is pressed
@@ -41,7 +40,7 @@ class MainActivity : AppCompatActivity() {
         if (savedInstanceState != null) {
             with(savedInstanceState) {
                 tapCount = getInt(STATE_TAPS)
-                tapPower = getInt(STATE_TAPPOW)
+                tapPower = getInt(STATE_TAP_POWER)
                 idlePower = getInt(STATE_IDLEPOW)
                 upgrades = getIntArray(STATE_UPGRADES)!!
 
@@ -83,7 +82,7 @@ class MainActivity : AppCompatActivity() {
         super.onSaveInstanceState(outState)
         outState.run {
             putInt(STATE_TAPS, tapCount)
-            putInt(STATE_TAPPOW, tapPower)
+            putInt(STATE_TAP_POWER, tapPower)
             putInt(STATE_IDLEPOW, idlePower)
             putIntArray(STATE_UPGRADES, upgrades)
         }

app/src/main/java/com/example/idletapperversion2/StoreActivity.kt

@@ -12,15 +12,16 @@ import com.example.idletapperversion2.databinding.ActivityStoreBinding
 
 class StoreActivity : AppCompatActivity() {
 
+    //You shouldn't really need to define an identical companion object twice. Rather, access it on
+    //the activity instance via dot notation.
     companion object {
         const val STATE_TAPS = "tapCount"
         const val STATE_TAPPOW = "tapPower"
-        const val STATE_IDLEPOW = "idlePower"
+        const val STATE_IDLE_POWER = "idlePower" //As in MainActivity
         const val STATE_UPGRADES = "upgrades"
     }
 
-    val TAG = "storeActivity"
-
+//As in MainActivity
     //flag to prevent overwriting loaded savedInstanceState variables with extras from MainActivity
     private var savedState = false
 
@@ -61,7 +62,7 @@ class StoreActivity : AppCompatActivity() {
             with(savedInstanceState) {
                 tapCount = getInt(STATE_TAPS)
                 tapPower = getInt(STATE_TAPPOW)
-                idlePower = getInt(STATE_IDLEPOW)
+                idlePower = getInt(STATE_IDLE_POWER)
                 upgrades = getIntArray(STATE_UPGRADES)!!
 
                 savedState = true
@@ -100,9 +101,9 @@ class StoreActivity : AppCompatActivity() {
     override fun onSaveInstanceState(outState: Bundle) {
         super.onSaveInstanceState(outState)
         outState.run {
-            putInt(STATE_TAPS, tapCount)
+            putInt(intent.extras?.getString(STATE_TAPS), tapCount) // See comment above regarding companion objects
             putInt(STATE_TAPPOW, tapPower)
-            putInt(STATE_IDLEPOW, idlePower)
+            putInt(STATE_IDLE_POWER, idlePower)
             putIntArray(STATE_UPGRADES, upgrades)
         }
 

app/src/main/java/com/example/idletapperversion2/adapter/ItemAdapter.kt

@@ -63,6 +63,10 @@ class ItemAdapter(
             item.baseCost, item.costIncreaseFactor,
             store.upgrades[item.upgradeIndex]
         )
+//        You may have noticed the "No speakable text present" error in your list_item.xml file.
+//        The preferred, and more accessible way to manage this is not to put dynamic text directly
+//        on a button. Rather, you should include a small 'Purchase' button on the right hand side
+//        your list_item view and place the text as a label in a regular TextView.
         holder.binding.storeButton.text = context.resources.getString(
             item.stringResourceID,
             store.upgrades[item.upgradeIndex], upgradeCost

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

@@ -7,11 +7,12 @@
     tools:context=".MainActivity">
 
     <!--    Note the change to snake_case for IDs. This is a more idiomatic approach -->
+<!--    snake_case is still preferred for ID names. :) -->
     <!--    Note also the extracted string resource in the first Button - this should be done for all views-->
     <!--    The width and height choices look fairly arbitrary - this is going to bite you if you try to load this app on a small screen. Better to no define them unless necessary, and rarely should you define width and height large enough to cause problems on smaller screens - such as with the main tap button. -->
 
     <TextView
-        android:id="@+id/tapPowerText"
+        android:id="@+id/tap_power_text"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_marginStart="16dp"
@@ -43,7 +44,7 @@
         app:layout_constraintBottom_toTopOf="@id/storeButton"
         app:layout_constraintEnd_toEndOf="parent"
         app:layout_constraintStart_toStartOf="parent"
-        app:layout_constraintTop_toBottomOf="@id/tapPowerText" />
+        app:layout_constraintTop_toBottomOf="@id/tap_power_text" />
 
     <TextView
         android:id="@+id/tapCounter"