fix(navigator): configuration handling

app/src/main/java/com/owncloud/android/ui/fragment/ActivitiesFragment.kt

@@ -60,48 +60,45 @@ class ActivitiesFragment :
     @Inject
     lateinit var userAccountManager: UserAccountManager
 
-    private var _binding: FragmentActivitiesBinding? = null
-    internal val binding get() = _binding!!
+    private var binding: FragmentActivitiesBinding? = null
 
     private var adapter: ActivityListAdapter? = null
     private var lastGiven: Long = 0
     private var isLoadingActivities = false
     private var actionListener: ActivitiesContract.ActionListener? = null
 
     override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View {
-        _binding = FragmentActivitiesBinding.inflate(inflater, container, false)
+        binding = FragmentActivitiesBinding.inflate(inflater, container, false)
+        val binding = binding!!
         return binding.root
     }
 
     override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
         super.onViewCreated(view, savedInstanceState)
         actionListener = ActivitiesPresenter(activitiesRepository, filesRepository, this)
-        viewThemeUtils.androidx.themeSwipeRefreshLayout(binding.swipeContainingList)
-        binding.swipeContainingList.setOnRefreshListener {
+        binding?.swipeContainingList?.let { viewThemeUtils.androidx.themeSwipeRefreshLayout(it) }
+        binding?.swipeContainingList?.setOnRefreshListener {
             lastGiven = ActivitiesContract.ActionListener.UNDEFINED.toLong()
             actionListener?.loadActivities(lifecycleScope, lastGiven)
         }
         setupContent()
     }
 
     private fun setupContent() {
-        binding.emptyList.emptyListIcon.setImageResource(R.drawable.ic_activity)
-
+        binding?.emptyList?.emptyListIcon?.setImageResource(R.drawable.ic_activity)
         adapter = ActivityListAdapter(
             requireActivity(),
             userAccountManager,
             this,
             false,
             viewThemeUtils
         )
-        binding.list.adapter = adapter
-
+        binding?.list?.adapter = adapter
         val layoutManager = LinearLayoutManager(requireContext())
-        binding.list.run {
+        binding?.list?.run {
             setLayoutManager(layoutManager)
             addOnScrollListener(getOnScrollListener(layoutManager))
         }
-
         actionListener?.loadActivities(lifecycleScope, ActivitiesContract.ActionListener.UNDEFINED.toLong())
     }
 
@@ -138,6 +135,7 @@ class ActivitiesFragment :
     }
 
     override fun showActivities(activities: List<Any>, client: NextcloudClient, lastGiven: Long) {
+        val binding = binding ?: return
         val clear = this.lastGiven == ActivitiesContract.ActionListener.UNDEFINED.toLong()
         adapter?.setActivityItems(activities, client, clear)
         this.lastGiven = lastGiven
@@ -157,6 +155,7 @@ class ActivitiesFragment :
     }
 
     override fun showActivitiesLoadError(error: String) {
+        val binding = binding ?: return
         connectivityService.isNetworkAndServerAvailable {
             if (it) {
                 DisplayUtils.showSnackMessage(requireView(), error)
@@ -192,11 +191,11 @@ class ActivitiesFragment :
     }
 
     override fun showLoadingMessage() {
-        binding.emptyList.emptyListView.visibility = View.GONE
+        binding?.emptyList?.emptyListView?.visibility = View.GONE
     }
 
     override fun showEmptyContent(headline: String, message: String) {
-        binding.run {
+        binding?.run {
             emptyList.emptyListViewHeadline.text = headline
             emptyList.emptyListViewText.text = message
             loadingContent.visibility = View.GONE
@@ -208,6 +207,7 @@ class ActivitiesFragment :
     }
 
     override fun setProgressIndicatorState(isActive: Boolean) {
+        val binding = binding ?: return
         isLoadingActivities = isActive
         if (adapter?.isEmpty() == false) {
             binding.swipeContainingList.post { binding.swipeContainingList.isRefreshing = isActive }
@@ -216,6 +216,6 @@ class ActivitiesFragment :
 
     override fun onDestroyView() {
         super.onDestroyView()
-        _binding = null
+        binding = null
     }
 }

app/src/main/java/com/owncloud/android/ui/fragment/community/CommunityFragment.kt

@@ -22,20 +22,20 @@ import javax.inject.Inject
 
 class CommunityFragment : Fragment() {
 
-    private var _binding: FragmentCommunityBinding? = null
-    private val binding get() = _binding!!
+    private var binding: FragmentCommunityBinding? = null
 
     @Inject
     lateinit var viewThemeUtils: ViewThemeUtils
 
     override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View {
-        _binding = FragmentCommunityBinding.inflate(inflater, container, false)
+        binding = FragmentCommunityBinding.inflate(inflater, container, false)
+        val binding = binding!!
         return binding.root
     }
 
     override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
         super.onViewCreated(view, savedInstanceState)
-        binding.communityReleaseCandidateText.movementMethod = LinkMovementMethod.getInstance()
+        binding?.communityReleaseCandidateText?.movementMethod = LinkMovementMethod.getInstance()
         setupViews()
         setOnClickListeners()
     }
@@ -49,7 +49,7 @@ class CommunityFragment : Fragment() {
         val contributingLink = getString(R.string.contributing_link)
 
         listOf(
-            binding.communityContributeForumText to
+            binding?.communityContributeForumText to
                 "${getString(R.string.community_contribute_forum_text)} " +
                 getString(
                     R.string.community_contribute_forum_text_link,
@@ -58,15 +58,15 @@ class CommunityFragment : Fragment() {
                     forum
                 ),
 
-            binding.communityContributeTranslateText to
+            binding?.communityContributeTranslateText to
                 getString(
                     R.string.community_contribute_translate_link,
                     primaryColor,
                     translationLink,
                     translate
                 ) + " " + getString(R.string.community_contribute_translate_text),
 
-            binding.communityContributeGithubText to
+            binding?.communityContributeGithubText to
                 getString(
                     R.string.community_contribute_github_text,
                     getString(
@@ -76,11 +76,11 @@ class CommunityFragment : Fragment() {
                     )
                 )
         ).forEach { (view, content) ->
-            view.setHtmlContent(content)
+            view?.setHtmlContent(content)
         }
 
-        viewThemeUtils.material.colorMaterialButtonPrimaryFilled(binding.communityTestingReport)
-        binding.communityTestingReport.setOnClickListener {
+        binding?.communityTestingReport?.let { viewThemeUtils.material.colorMaterialButtonPrimaryFilled(it) }
+        binding?.communityTestingReport?.setOnClickListener {
             DisplayUtils.startLinkIntent(requireActivity(), R.string.report_issue_empty_link)
         }
     }
@@ -89,19 +89,19 @@ class CommunityFragment : Fragment() {
         val activity = requireActivity()
 
         listOf(
-            binding.communityBetaFdroid to R.string.fdroid_beta_link,
-            binding.communityReleaseCandidateFdroid to R.string.fdroid_link,
-            binding.communityReleaseCandidatePlaystore to R.string.play_store_register_beta,
-            binding.communityBetaApk to R.string.beta_apk_link
+            binding?.communityBetaFdroid to R.string.fdroid_beta_link,
+            binding?.communityReleaseCandidateFdroid to R.string.fdroid_link,
+            binding?.communityReleaseCandidatePlaystore to R.string.play_store_register_beta,
+            binding?.communityBetaApk to R.string.beta_apk_link
         ).forEach { (view, linkRes) ->
-            view.setOnClickListener {
+            view?.setOnClickListener {
                 DisplayUtils.startLinkIntent(activity, linkRes)
             }
         }
     }
 
     override fun onDestroyView() {
         super.onDestroyView()
-        _binding = null
+        binding = null
     }
 }

app/src/main/java/com/owncloud/android/ui/navigation/Navigator.kt

@@ -38,4 +38,11 @@ class Navigator(private val fragmentManager: FragmentManager, private val fragme
         fragmentManager.popBackStack()
         return stack.lastOrNull()
     }
+
+    fun getTopScreen(): NavigatorScreen? {
+        val topTag = fragmentManager
+            .getBackStackEntryAt(fragmentManager.backStackEntryCount - 1)
+            .name
+        return NavigatorScreen.fromTag(topTag)
+    }
 }

app/src/main/java/com/owncloud/android/ui/navigation/NavigatorActivity.kt

@@ -12,6 +12,7 @@ import android.content.Intent
 import android.os.Bundle
 import android.view.MenuItem
 import androidx.activity.OnBackPressedCallback
+import androidx.fragment.app.Fragment
 import androidx.fragment.app.FragmentContainerView
 import com.nextcloud.utils.extensions.getParcelableArgument
 import com.owncloud.android.R
@@ -22,21 +23,50 @@ class NavigatorActivity : DrawerActivity() {
 
     private lateinit var navigator: Navigator
 
+    // region Lifecycle Methods
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         setContentView(R.layout.activity_navigator)
 
         val screen = intent.getParcelableArgument(EXTRA_SCREEN, NavigatorScreen::class.java) ?: return
         val fragmentContainerView = findViewById<FragmentContainerView>(R.id.fragment_container_view)
         navigator = Navigator(supportFragmentManager, fragmentContainerView)
-
         setupBackPressedHandler()
-        push(screen)
-        supportFragmentManager.addFragmentOnAttachListener { _, fragment ->
-            AndroidSupportInjection.inject(fragment)
+        pushOrRestoreScreen(savedInstanceState, screen)
+    }
+
+    // addFragmentOnAttachListener or via registerFragmentLifecycleCallbacks not providing same result
+    @Suppress("DEPRECATION")
+    @Deprecated("Deprecated in Java")
+    override fun onAttachFragment(fragment: Fragment) {
+        AndroidSupportInjection.inject(fragment)
+        super.onAttachFragment(fragment)
+    }
+
+    override fun onOptionsItemSelected(item: MenuItem): Boolean {
+        if (item.itemId == android.R.id.home) {
+            if (isDrawerOpen) {
+                closeDrawer()
+            } else {
+                openDrawer()
+            }
+            return true
         }
+        return super.onOptionsItemSelected(item)
+    }
+
+    override fun getMenuItemId(): Int {
+        val screen = intent.getParcelableArgument(EXTRA_SCREEN, NavigatorScreen::class.java)
+        return screen?.menuItemId() ?: super.getMenuItemId()
+    }
+
+    override fun onResume() {
+        super.onResume()
+        highlightOrRestoreNavigationViewItem()
     }
+    // endregion
 
+    // region Public Methods
     fun pop() {
         val previousScreen = navigator.pop() ?: return
         setupActionBar(previousScreen)
@@ -46,6 +76,18 @@ class NavigatorActivity : DrawerActivity() {
         setupActionBar(screen)
         navigator.push(screen)
     }
+    // endregion
+
+    // region Private Methods
+    private fun pushOrRestoreScreen(savedInstanceState: Bundle?, screen: NavigatorScreen) {
+        if (savedInstanceState == null) {
+            push(screen)
+        } else {
+            val currentScreen = navigator.getTopScreen() ?: screen
+            setupActionBar(currentScreen)
+            highlightNavigationViewItem(currentScreen.menuItemId())
+        }
+    }
 
     private fun setupActionBar(screen: NavigatorScreen) {
         val (style, titleId) = screen.actionBarStyle()
@@ -73,27 +115,15 @@ class NavigatorActivity : DrawerActivity() {
         )
     }
 
-    override fun onOptionsItemSelected(item: MenuItem): Boolean {
-        if (item.itemId == android.R.id.home) {
-            if (isDrawerOpen) {
-                closeDrawer()
-            } else {
-                openDrawer()
-            }
-            return true
+    private fun highlightOrRestoreNavigationViewItem() {
+        val currentScreen = navigator.getTopScreen()
+        if (currentScreen != null) {
+            highlightNavigationViewItem(currentScreen.menuItemId())
+        } else {
+            highlightNavigationViewItem(menuItemId)
         }
-        return super.onOptionsItemSelected(item)
-    }
-
-    override fun getMenuItemId(): Int {
-        val screen = intent.getParcelableArgument(EXTRA_SCREEN, NavigatorScreen::class.java)
-        return screen?.menuItemId() ?: super.getMenuItemId()
-    }
-
-    override fun onResume() {
-        super.onResume()
-        highlightNavigationViewItem(menuItemId)
     }
+    // endregion
 
     companion object {
         const val EXTRA_SCREEN = "extra_screen"

app/src/main/java/com/owncloud/android/ui/navigation/NavigatorScreen.kt

@@ -17,10 +17,21 @@ import kotlinx.parcelize.Parcelize
 sealed class NavigatorScreen(val tag: String) : Parcelable {
 
     @Parcelize
-    object Activities : NavigatorScreen("Activities")
+    object Activities : NavigatorScreen(ACTIVITIES_TAG)
 
     @Parcelize
-    object Community : NavigatorScreen("Community")
+    object Community : NavigatorScreen(COMMUNITY_TAG)
+
+    companion object {
+        private const val ACTIVITIES_TAG = "Activities"
+        private const val COMMUNITY_TAG = "Community"
+
+        fun fromTag(tag: String?): NavigatorScreen? = when (tag) {
+            ACTIVITIES_TAG -> Activities
+            COMMUNITY_TAG -> Community
+            else -> null
+        }
+    }
 
     fun menuItemId(): Int = when (this) {
         Community -> R.id.nav_community