For #3563. Use `ListAdapter` for App Share list.

app/src/main/java/org/mozilla/fenix/share/ShareFragment.kt

@@ -157,7 +157,7 @@ class ShareFragment : AppCompatDialogFragment() {
             val devicesShareOptions = devicesListDeferred.await()
             shareToAccountDevicesView.setSharetargets(devicesShareOptions)
             val appsToShareTo = appsListDeferred.await()
-            shareToAppsView.setSharetargets(appsToShareTo)
+            shareToAppsView.setShareTargets(appsToShareTo)
         }
     }
 

app/src/main/java/org/mozilla/fenix/share/ShareToAppsView.kt

@@ -8,10 +8,10 @@ import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
 import kotlinx.android.extensions.LayoutContainer
-import org.mozilla.fenix.R
-import org.mozilla.fenix.share.listadapters.AppShareOption
 import kotlinx.android.synthetic.main.share_to_apps.*
+import org.mozilla.fenix.R
 import org.mozilla.fenix.share.listadapters.AppShareAdapter
+import org.mozilla.fenix.share.listadapters.AppShareOption
 
 /**
  * Callbacks for possible user interactions on the [ShareCloseView]
@@ -24,19 +24,20 @@ class ShareToAppsView(
     override val containerView: ViewGroup,
     interactor: ShareToAppsInteractor
 ) : LayoutContainer {
+
+    private val adapter = AppShareAdapter(interactor)
+
     init {
         LayoutInflater.from(containerView.context)
             .inflate(R.layout.share_to_apps, containerView, true)
 
-        appsList.adapter = AppShareAdapter(interactor)
+        appsList.adapter = adapter
     }
 
-    fun setSharetargets(targets: List<AppShareOption>) {
+    fun setShareTargets(targets: List<AppShareOption>) {
         progressBar.visibility = View.GONE
         appsList.visibility = View.VISIBLE
 
-        with(appsList.adapter as AppShareAdapter) {
-            updateData(targets)
-        }
+        adapter.submitList(targets)
     }
 }

app/src/main/java/org/mozilla/fenix/share/listadapters/AppShareAdapter.kt

@@ -7,14 +7,14 @@ package org.mozilla.fenix.share.listadapters
 import android.graphics.drawable.Drawable
 import android.view.LayoutInflater
 import android.view.ViewGroup
-import androidx.recyclerview.widget.RecyclerView
+import androidx.recyclerview.widget.DiffUtil
+import androidx.recyclerview.widget.ListAdapter
 import org.mozilla.fenix.share.ShareToAppsInteractor
 import org.mozilla.fenix.share.viewholders.AppViewHolder
 
 class AppShareAdapter(
-    private val interactor: ShareToAppsInteractor,
-    private val applications: MutableList<AppShareOption> = mutableListOf()
-) : RecyclerView.Adapter<AppViewHolder>() {
+    private val interactor: ShareToAppsInteractor
+) : ListAdapter<AppShareOption, AppViewHolder>(DiffCallback) {
 
     override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): AppViewHolder {
         val view = LayoutInflater.from(parent.context)
@@ -23,17 +23,18 @@ class AppShareAdapter(
         return AppViewHolder(view, interactor)
     }
 
-    override fun getItemCount(): Int = applications.size
-
     override fun onBindViewHolder(holder: AppViewHolder, position: Int) {
-        holder.bind(applications[position])
+        holder.bind(getItem(position))
     }
+}
 
-    fun updateData(applications: List<AppShareOption>) {
-        this.applications.clear()
-        this.applications.addAll(applications)
-        notifyDataSetChanged()
-    }
+private object DiffCallback : DiffUtil.ItemCallback<AppShareOption>() {
+
+    override fun areItemsTheSame(oldItem: AppShareOption, newItem: AppShareOption) =
+        oldItem.packageName == newItem.packageName
+
+    override fun areContentsTheSame(oldItem: AppShareOption, newItem: AppShareOption) =
+        oldItem == newItem
 }
 
 data class AppShareOption(

app/src/test/java/org/mozilla/fenix/share/listadapters/AppShareAdapterTest.kt

@@ -28,26 +28,25 @@ import org.robolectric.annotation.Config
 @RunWith(RobolectricTestRunner::class)
 @Config(application = TestApplication::class)
 class AppShareAdapterTest {
+
     private val appOptions = mutableListOf(
         AppShareOption("App 0", mockk(), "package 0", "activity 0"),
         AppShareOption("App 1", mockk(), "package 1", "activity 1")
     )
-    private val appOptionsEmpty = mutableListOf<AppShareOption>()
+    private val appOptionsEmpty = emptyList<AppShareOption>()
     private val interactor: ShareInteractor = mockk(relaxed = true)
 
     @Test
-    fun `updateData should replace all previous data with argument and call notifyDataSetChanged()`() {
-        // Used AppShareAdapter as a spy to ease testing of notifyDataSetChanged()
+    fun `updateData should call submitList()`() {
+        // Used AppShareAdapter as a spy to ease testing of submitList()
         // and appOptionsEmpty to be able to record them being called
-        val adapter = spyk(AppShareAdapter(mockk(), appOptionsEmpty))
-        every { adapter.notifyDataSetChanged() } just Runs
+        val adapter = spyk(AppShareAdapter(mockk()).apply { submitList(appOptionsEmpty) })
+        every { adapter.submitList(any()) } just Runs
 
-        adapter.updateData(appOptions)
+        adapter.submitList(appOptions)
 
         verifyOrder {
-            appOptionsEmpty.clear()
-            appOptionsEmpty.addAll(appOptions)
-            adapter.notifyDataSetChanged()
+            adapter.submitList(appOptions)
         }
     }
 
@@ -60,7 +59,7 @@ class AppShareAdapterTest {
 
     @Test
     fun `getItemCount after updateData() call should return the the passed in list's size`() {
-        val adapter = AppShareAdapter(mockk(), appOptions)
+        val adapter = AppShareAdapter(mockk()).apply { submitList(appOptions) }
 
         assertThat(adapter.itemCount).isEqualTo(2)
     }
@@ -89,7 +88,7 @@ class AppShareAdapterTest {
 
     @Test
     fun `the adapter binds the right item to a ViewHolder`() {
-        val adapter = AppShareAdapter(interactor, appOptions)
+        val adapter = AppShareAdapter(interactor).apply { submitList(appOptions) }
         val parentView: ViewGroup = mockk(relaxed = true)
         val itemView: ViewGroup = mockk(relaxed = true)
         every { parentView.context } returns testContext