Consolidate session star click handling

Consolidates all session star click handling into one class that can be
injected into all ViewModels that need it. This also decouples session
click handling from session star click handling.

Change-Id: I780157b1df0916d9db9b6216c8836e3c96689c62

Author: jdkoren

mobile/src/main/java/com/google/samples/apps/iosched/ui/feed/FeedViewModel.kt

@@ -47,7 +47,8 @@ import com.google.samples.apps.iosched.shared.util.toEpochMilli
 import com.google.samples.apps.iosched.shared.util.tryOffer
 import com.google.samples.apps.iosched.ui.messages.SnackbarMessage
 import com.google.samples.apps.iosched.ui.messages.SnackbarMessageManager
-import com.google.samples.apps.iosched.ui.sessioncommon.EventActions
+import com.google.samples.apps.iosched.ui.sessioncommon.OnSessionClickListener
+import com.google.samples.apps.iosched.ui.sessioncommon.OnSessionStarClickListener
 import com.google.samples.apps.iosched.ui.signin.SignInViewModelDelegate
 import com.google.samples.apps.iosched.ui.theme.ThemedActivityDelegate
 import com.google.samples.apps.iosched.util.WhileViewSubscribed
@@ -315,7 +316,7 @@ class FeedViewModel @Inject constructor(
     }
 }
 
-interface FeedEventListener : EventActions {
+interface FeedEventListener : OnSessionClickListener, OnSessionStarClickListener {
     fun openSchedule(showOnlyPinnedSessions: Boolean)
     fun signIn()
     fun openMap(moment: Moment)

mobile/src/main/java/com/google/samples/apps/iosched/ui/schedule/ScheduleFragment.kt

@@ -158,11 +158,12 @@ class ScheduleFragment : Fragment() {
 
         // Session list configuration
         sessionsAdapter = SessionsAdapter(
-            scheduleTwoPaneViewModel,
             tagViewPool,
             scheduleViewModel.showReservations,
             scheduleViewModel.timeZoneId,
-            viewLifecycleOwner
+            viewLifecycleOwner,
+            scheduleTwoPaneViewModel, // OnSessionClickListener
+            scheduleTwoPaneViewModel // OnSessionStarClickListener
         )
         scheduleRecyclerView.apply {
             adapter = sessionsAdapter

mobile/src/main/java/com/google/samples/apps/iosched/ui/schedule/ScheduleItemBindingAdapter.kt

@@ -38,11 +38,12 @@ import org.threeten.bp.ZonedDateTime
 )
 fun sessionDateTimeLocation(
     textView: TextView,
-    startTime: ZonedDateTime,
+    startTime: ZonedDateTime?,
     zoneId: ZoneId?,
     showTime: Boolean,
     room: Room?
 ) {
+    startTime ?: return
     zoneId ?: return
     val roomName = room?.name ?: "-"
     val localStartTime = TimeUtils.zonedTime(startTime, zoneId)

mobile/src/main/java/com/google/samples/apps/iosched/ui/schedule/ScheduleTwoPaneFragment.kt

@@ -23,21 +23,21 @@ import android.view.ViewGroup
 import androidx.activity.OnBackPressedCallback
 import androidx.core.view.doOnNextLayout
 import androidx.fragment.app.activityViewModels
-import androidx.lifecycle.lifecycleScope
 import androidx.navigation.NavController
 import androidx.navigation.NavDestination
 import androidx.navigation.fragment.NavHostFragment
 import androidx.slidingpanelayout.widget.SlidingPaneLayout
 import com.google.samples.apps.iosched.R
 import com.google.samples.apps.iosched.ScheduleDetailNavGraphDirections
 import com.google.samples.apps.iosched.databinding.FragmentScheduleTwoPaneBinding
-import com.google.samples.apps.iosched.shared.result.EventObserver
 import com.google.samples.apps.iosched.ui.MainNavigationFragment
 import com.google.samples.apps.iosched.ui.messages.SnackbarMessageManager
 import com.google.samples.apps.iosched.ui.messages.setupSnackbarManager
 import com.google.samples.apps.iosched.ui.signin.SignInDialogFragment
+import com.google.samples.apps.iosched.util.launchAndRepeatWithViewLifecycle
 import dagger.hilt.android.AndroidEntryPoint
 import kotlinx.coroutines.flow.collect
+import kotlinx.coroutines.launch
 import javax.inject.Inject
 
 @AndroidEntryPoint
@@ -89,30 +89,28 @@ class ScheduleTwoPaneFragment : MainNavigationFragment() {
             scheduleTwoPaneViewModel.setIsTwoPane(!binding.slidingPaneLayout.isSlideable)
         }
 
-        scheduleTwoPaneViewModel.navigateToSessionAction.observe(
-            viewLifecycleOwner,
-            EventObserver { sessionId ->
-                detailPaneNavController.navigate(
-                    ScheduleDetailNavGraphDirections.toSessionDetail(sessionId)
-                )
-                // On narrow screens, slide the detail pane over the list pane if it isn't already
-                // on top. If both panes are visible, this will have no effect.
-                binding.slidingPaneLayout.open()
+        launchAndRepeatWithViewLifecycle {
+            launch {
+                scheduleTwoPaneViewModel.selectSessionEvents.collect { sessionId ->
+                    detailPaneNavController.navigate(
+                        ScheduleDetailNavGraphDirections.toSessionDetail(sessionId)
+                    )
+                    // On narrow screens, slide the detail pane over the list pane if it isn't already
+                    // on top. If both panes are visible, this will have no effect.
+                    binding.slidingPaneLayout.open()
+                }
             }
-        )
-
-        lifecycleScope.launchWhenStarted {
-            scheduleTwoPaneViewModel.returnToListPaneEvents.collect {
-                binding.slidingPaneLayout.close()
+            launch {
+                scheduleTwoPaneViewModel.navigateToSignInDialogEvents.collect {
+                    openSignInDialog()
+                }
             }
-        }
-
-        scheduleTwoPaneViewModel.navigateToSignInDialogAction.observe(
-            viewLifecycleOwner,
-            EventObserver {
-                openSignInDialog()
+            launch {
+                scheduleTwoPaneViewModel.returnToListPaneEvents.collect {
+                    binding.slidingPaneLayout.close()
+                }
             }
-        )
+        }
 
         requireActivity().onBackPressedDispatcher.addCallback(viewLifecycleOwner, backPressHandler)
     }

mobile/src/main/java/com/google/samples/apps/iosched/ui/schedule/ScheduleTwoPaneViewModel.kt

@@ -17,8 +17,10 @@
 package com.google.samples.apps.iosched.ui.schedule
 
 import androidx.lifecycle.ViewModel
+import com.google.samples.apps.iosched.model.SessionId
 import com.google.samples.apps.iosched.shared.util.tryOffer
-import com.google.samples.apps.iosched.ui.sessioncommon.EventActionsViewModelDelegate
+import com.google.samples.apps.iosched.ui.sessioncommon.OnSessionClickListener
+import com.google.samples.apps.iosched.ui.sessioncommon.OnSessionStarClickDelegate
 import dagger.hilt.android.lifecycle.HiltViewModel
 import kotlinx.coroutines.channels.Channel
 import kotlinx.coroutines.flow.MutableStateFlow
@@ -29,20 +31,29 @@ import javax.inject.Inject
 // Note: clients should obtain this from the Activity.
 @HiltViewModel
 class ScheduleTwoPaneViewModel @Inject constructor(
-    eventActionsViewModelDelegate: EventActionsViewModelDelegate
-) : ViewModel(), EventActionsViewModelDelegate by eventActionsViewModelDelegate {
+    onSessionStarClickDelegate: OnSessionStarClickDelegate
+) : ViewModel(),
+    OnSessionClickListener,
+    OnSessionStarClickDelegate by onSessionStarClickDelegate {
 
     private val _isTwoPane = MutableStateFlow(false)
     val isTwoPane: StateFlow<Boolean> = _isTwoPane
 
     private val _returnToListPaneEvents = Channel<Unit>(capacity = Channel.CONFLATED)
     val returnToListPaneEvents = _returnToListPaneEvents.receiveAsFlow()
 
+    private val _selectSessionEvents = Channel<SessionId>(capacity = Channel.CONFLATED)
+    val selectSessionEvents = _selectSessionEvents.receiveAsFlow()
+
     fun setIsTwoPane(isTwoPane: Boolean) {
         _isTwoPane.value = isTwoPane
     }
 
     fun returnToListPane() {
         _returnToListPaneEvents.tryOffer(Unit)
     }
+
+    override fun openEventDetail(id: SessionId) {
+        _selectSessionEvents.tryOffer(id)
+    }
 }

mobile/src/main/java/com/google/samples/apps/iosched/ui/schedule/ScheduleViewModel.kt

@@ -79,7 +79,7 @@ class ScheduleViewModel @Inject constructor(
     private val snackbarMessageManager: SnackbarMessageManager,
     getTimeZoneUseCase: GetTimeZoneUseCase,
     private val refreshConferenceDataUseCase: RefreshConferenceDataUseCase,
-    observeConferenceDataUseCase: ObserveConferenceDataUseCase,
+    observeConferenceDataUseCase: ObserveConferenceDataUseCase
 ) : ViewModel(),
     SignInViewModelDelegate by signInViewModelDelegate {
 
@@ -211,9 +211,7 @@ class ScheduleViewModel @Inject constructor(
                 // Setting smoothScroll to false as it's an unnecessary delay.
                 emit(ScheduleScrollEvent(currentEventIndex, smoothScroll = false))
             } else {
-                val index =
-                    (result as? Success)?.data?.firstUnfinishedSessionIndex
-                        ?: return@combineTransform
+                val index = result.data?.firstUnfinishedSessionIndex ?: return@combineTransform
                 if (index != -1) {
                     emit(ScheduleScrollEvent(index))
                 }

mobile/src/main/java/com/google/samples/apps/iosched/ui/search/SearchFragment.kt

@@ -113,11 +113,12 @@ class SearchFragment : Fragment() {
         }
 
         sessionsAdapter = SessionsAdapter(
-            scheduleTwoPaneViewModel,
             tagViewPool,
             viewModel.showReservations,
             viewModel.timeZoneId,
-            viewLifecycleOwner
+            viewLifecycleOwner,
+            scheduleTwoPaneViewModel, // OnSessionClickListener
+            scheduleTwoPaneViewModel // OnSessionStarClickListener
         )
         binding.recyclerView.apply {
             adapter = sessionsAdapter

mobile/src/main/java/com/google/samples/apps/iosched/ui/sessioncommon/EventActions.kt

@@ -22,7 +22,10 @@ import com.google.samples.apps.iosched.model.userdata.UserSession
 /**
  * Actions that can be performed on events.
  */
-interface EventActions {
+interface OnSessionClickListener {
     fun openEventDetail(id: SessionId)
+}
+
+interface OnSessionStarClickListener {
     fun onStarClicked(userSession: UserSession)
 }

mobile/src/main/java/com/google/samples/apps/iosched/ui/sessioncommon/EventActionsViewModelDelegate.kt renamed to mobile/src/main/java/com/google/samples/apps/iosched/ui/sessioncommon/OnSessionStarClickDelegate.kt

@@ -16,63 +16,53 @@
 
 package com.google.samples.apps.iosched.ui.sessioncommon
 
-import androidx.lifecycle.LiveData
-import androidx.lifecycle.MutableLiveData
 import com.google.samples.apps.iosched.R
-import com.google.samples.apps.iosched.model.SessionId
 import com.google.samples.apps.iosched.model.userdata.UserSession
 import com.google.samples.apps.iosched.shared.analytics.AnalyticsActions
 import com.google.samples.apps.iosched.shared.analytics.AnalyticsHelper
 import com.google.samples.apps.iosched.shared.di.ApplicationScope
 import com.google.samples.apps.iosched.shared.di.MainDispatcher
 import com.google.samples.apps.iosched.shared.domain.users.StarEventAndNotifyUseCase
 import com.google.samples.apps.iosched.shared.domain.users.StarEventParameter
-import com.google.samples.apps.iosched.shared.result.Event
 import com.google.samples.apps.iosched.shared.result.Result
+import com.google.samples.apps.iosched.shared.util.tryOffer
 import com.google.samples.apps.iosched.ui.messages.SnackbarMessage
 import com.google.samples.apps.iosched.ui.messages.SnackbarMessageManager
 import com.google.samples.apps.iosched.ui.signin.SignInViewModelDelegate
 import kotlinx.coroutines.CoroutineDispatcher
 import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.channels.Channel
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.receiveAsFlow
 import kotlinx.coroutines.launch
 import timber.log.Timber
 import java.util.UUID
 import javax.inject.Inject
 
 /**
- * A delegate providing common functionality for displaying a list of events and responding to
- * actions performed on them.
+ * A delegate providing common functionality for starring events.
  */
-interface EventActionsViewModelDelegate : EventActions {
-    val navigateToSessionAction: LiveData<Event<SessionId>>
-    val navigateToSignInDialogAction: LiveData<Event<Unit>>
+
+interface OnSessionStarClickDelegate : OnSessionStarClickListener {
+    val navigateToSignInDialogEvents: Flow<Unit>
 }
 
-class DefaultEventActionsViewModelDelegate @Inject constructor(
+class DefaultOnSessionStarClickDelegate @Inject constructor(
     signInViewModelDelegate: SignInViewModelDelegate,
     private val starEventUseCase: StarEventAndNotifyUseCase,
     private val snackbarMessageManager: SnackbarMessageManager,
     private val analyticsHelper: AnalyticsHelper,
     @ApplicationScope private val externalScope: CoroutineScope,
     @MainDispatcher private val mainDispatcher: CoroutineDispatcher
-) : EventActionsViewModelDelegate, SignInViewModelDelegate by signInViewModelDelegate {
-
-    private val _navigateToSessionAction = MutableLiveData<Event<SessionId>>()
-    override val navigateToSessionAction: LiveData<Event<SessionId>>
-        get() = _navigateToSessionAction
+) : OnSessionStarClickDelegate, SignInViewModelDelegate by signInViewModelDelegate {
 
-    private val _navigateToSignInDialogAction = MutableLiveData<Event<Unit>>()
-    override val navigateToSignInDialogAction: LiveData<Event<Unit>>
-        get() = _navigateToSignInDialogAction
-
-    override fun openEventDetail(id: SessionId) {
-        _navigateToSessionAction.value = Event(id)
-    }
+    private val _navigateToSignInDialogEvents = Channel<Unit>(capacity = Channel.CONFLATED)
+    override val navigateToSignInDialogEvents = _navigateToSignInDialogEvents.receiveAsFlow()
 
     override fun onStarClicked(userSession: UserSession) {
         if (!isUserSignedInValue) {
             Timber.d("Showing Sign-in dialog after star click")
-            _navigateToSignInDialogAction.value = Event(Unit)
+            _navigateToSignInDialogEvents.tryOffer(Unit)
             return
         }
         val newIsStarredState = !userSession.userEvent.isStarred
@@ -90,7 +80,6 @@ class DefaultEventActionsViewModelDelegate @Inject constructor(
                 requestChangeId = UUID.randomUUID().toString()
             )
         )
-
         if (newIsStarredState) {
             analyticsHelper.logUiEvent(userSession.session.title, AnalyticsActions.STARRED)
         }

mobile/src/main/java/com/google/samples/apps/iosched/ui/sessioncommon/EventActionsViewModelDelegateModule.kt renamed to mobile/src/main/java/com/google/samples/apps/iosched/ui/sessioncommon/OnSessionStarClickDelegateModule.kt

@@ -30,22 +30,22 @@ import kotlinx.coroutines.CoroutineDispatcher
 import kotlinx.coroutines.CoroutineScope
 
 /**
- * Provides a default implementation of [EventActionsViewModelDelegate].
+ * Provides a default implementation of [OnSessionStarClickDelegate].
  */
 @InstallIn(ViewModelComponent::class)
 @Module
-internal class EventActionsViewModelDelegateModule {
+internal class OnSessionStarClickDelegateModule {
 
     @Provides
-    fun provideEventActionsViewModelDelegate(
+    fun provideOnSessionStarClickDelegate(
         signInViewModelDelegate: SignInViewModelDelegate,
         starEventUseCase: StarEventAndNotifyUseCase,
         snackbarMessageManager: SnackbarMessageManager,
         analyticsHelper: AnalyticsHelper,
         @ApplicationScope applicationScope: CoroutineScope,
         @MainDispatcher mainDispatcher: CoroutineDispatcher
-    ): EventActionsViewModelDelegate {
-        return DefaultEventActionsViewModelDelegate(
+    ): OnSessionStarClickDelegate {
+        return DefaultOnSessionStarClickDelegate(
             signInViewModelDelegate,
             starEventUseCase,
             snackbarMessageManager,