Bug 1830874 - Update onSharedPreferenceChanged method signature.

onSharedPreferenceChanged now allows a nullable key String.

app/src/main/java/org/mozilla/fenix/settings/OnSharedPreferenceChangeListener.kt

@@ -6,11 +6,12 @@ package org.mozilla.fenix.settings
 
 import android.content.SharedPreferences
 import androidx.lifecycle.DefaultLifecycleObserver
+import androidx.lifecycle.LifecycleObserver
 import androidx.lifecycle.LifecycleOwner
 
 class OnSharedPreferenceChangeListener(
     private val sharedPreferences: SharedPreferences,
-    private val listener: (SharedPreferences, String) -> Unit,
+    private val listener: (SharedPreferences, String?) -> Unit,
 ) : SharedPreferences.OnSharedPreferenceChangeListener, DefaultLifecycleObserver {
 
     override fun onCreate(owner: LifecycleOwner) {
@@ -21,14 +22,17 @@ class OnSharedPreferenceChangeListener(
         sharedPreferences.unregisterOnSharedPreferenceChangeListener(this)
     }
 
-    override fun onSharedPreferenceChanged(sharedPreferences: SharedPreferences, key: String) {
+    override fun onSharedPreferenceChanged(sharedPreferences: SharedPreferences, key: String?) {
         listener(sharedPreferences, key)
     }
 }
 
+/**
+ * Registers a [OnSharedPreferenceChangeListener] as a [LifecycleObserver] for a preference.
+ */
 fun SharedPreferences.registerOnSharedPreferenceChangeListener(
     owner: LifecycleOwner,
-    listener: (SharedPreferences, String) -> Unit,
+    listener: (SharedPreferences, String?) -> Unit,
 ) {
     owner.lifecycle.addObserver(OnSharedPreferenceChangeListener(this, listener))
 }

app/src/test/java/org/mozilla/fenix/settings/OnSharedPreferenceChangeListenerTest.kt

@@ -20,7 +20,7 @@ import org.mozilla.fenix.helpers.FenixRobolectricTestRunner
 class OnSharedPreferenceChangeListenerTest {
 
     private lateinit var sharedPrefs: SharedPreferences
-    private lateinit var listener: (SharedPreferences, String) -> Unit
+    private lateinit var listener: (SharedPreferences, String?) -> Unit
     private lateinit var owner: LifecycleOwner
     private lateinit var lifecycleRegistry: LifecycleRegistry
 

detekt-baseline.xml

@@ -721,7 +721,6 @@
     <ID>UndocumentedPublicFunction:NavController.kt$fun NavController.navigateSafe( @IdRes resId: Int, directions: NavDirections, )</ID>
     <ID>UndocumentedPublicFunction:NimbusBranchesView.kt$NimbusBranchesView$fun update(state: NimbusBranchesState)</ID>
     <ID>UndocumentedPublicFunction:NotificationManager.kt$NotificationManager$fun showReceivedTabs(context: Context, device: Device?, tabs: List&lt;TabData&gt;)</ID>
-    <ID>UndocumentedPublicFunction:OnSharedPreferenceChangeListener.kt$fun SharedPreferences.registerOnSharedPreferenceChangeListener( owner: LifecycleOwner, listener: (SharedPreferences, String) -&gt; Unit, )</ID>
     <ID>UndocumentedPublicFunction:OnboardingRadioButton.kt$OnboardingRadioButton$fun addIllustration(illustration: ImageView)</ID>
     <ID>UndocumentedPublicFunction:OnboardingRadioButton.kt$OnboardingRadioButton$fun onClickListener(listener: () -&gt; Unit)</ID>
     <ID>UndocumentedPublicFunction:OnboardingSectionHeaderViewHolder.kt$OnboardingSectionHeaderViewHolder$fun bind(labelBuilder: (Context) -&gt; String)</ID>