Fixes details screen showing incorrect data during transition animations

Bug: 77988949 Change-Id: Idf302d99d6ccf27a275378839841ff9f7ac802a4
dattien96 · Apr 16, 2018 · 9541971 · 9541971
1 parent 06e39cf
commit 9541971
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Showing 4 changed files with 23 additions and 14 deletions.
diff --git a/.../src/main/java/com/google/samples/apps/iosched/ui/sessiondetail/SessionDetailViewModel.kt b/.../src/main/java/com/google/samples/apps/iosched/ui/sessiondetail/SessionDetailViewModel.kt
@@ -55,7 +55,7 @@ import org.threeten.bp.Duration
 import org.threeten.bp.ZoneId
 import org.threeten.bp.ZonedDateTime
 import timber.log.Timber
-import java.util.*
+import java.util.UUID
 import javax.inject.Inject
 
 private const val TEN_SECONDS = 10_000L
@@ -338,7 +338,6 @@ class SessionDetailViewModel @Inject constructor(
     override fun onCleared() {
         // Clear subscriptions that might be leaked or that will not be used in the future.
         loadUserSessionUseCase.onCleared()
-        loadRelatedSessionUseCase.onCleared()
     }
 
     /**

diff --git a/...google/samples/apps/iosched/shared/data/userevent/DefaultSessionAndUserEventRepository.kt b/...google/samples/apps/iosched/shared/data/userevent/DefaultSessionAndUserEventRepository.kt
@@ -50,7 +50,6 @@ open class DefaultSessionAndUserEventRepository @Inject constructor(
 ) : SessionAndUserEventRepository {
 
     private val sessionsByDayResult = MediatorLiveData<Result<LoadUserSessionsByDayUseCaseResult>>()
-    private val sessionResult = MediatorLiveData<Result<LoadUserSessionUseCaseResult>>()
 
     // Keep a reference to the observable for a single event (from the details screen) so we can
     // stop observing when done.
@@ -109,6 +108,7 @@ open class DefaultSessionAndUserEventRepository @Inject constructor(
             userId: String?,
             eventId: SessionId
     ): LiveData<Result<LoadUserSessionUseCaseResult>> {
+        val sessionResult = MediatorLiveData<Result<LoadUserSessionUseCaseResult>>()
 
         // If there is no logged-in user, return the session with a null UserEvent
         if (userId == null) {
@@ -253,12 +253,8 @@ open class DefaultSessionAndUserEventRepository @Inject constructor(
     }
 
     override fun clearSingleEventSubscriptions() {
-        // The details screen is closing so reset subscriptions and old values
-        sessionResult.value = null
         // The UserEvent data source can stop observing user data
         userEventDataSource.clearSingleEventSubscriptions()
-        // Also free its observable in the repository.
-        observableUserEvent?.let { sessionResult.removeSource(it) }
     }
 }
 

diff --git a/...ain/java/com/google/samples/apps/iosched/shared/domain/sessions/LoadUserSessionUseCase.kt b/...ain/java/com/google/samples/apps/iosched/shared/domain/sessions/LoadUserSessionUseCase.kt
@@ -16,6 +16,7 @@
 
 package com.google.samples.apps.iosched.shared.domain.sessions
 
+import android.arch.lifecycle.LiveData
 import com.google.samples.apps.iosched.shared.data.userevent.DefaultSessionAndUserEventRepository
 import com.google.samples.apps.iosched.shared.data.userevent.UserEventMessage
 import com.google.samples.apps.iosched.shared.domain.MediatorUseCase
@@ -29,13 +30,19 @@ open class LoadUserSessionUseCase @Inject constructor(
         private val userEventRepository: DefaultSessionAndUserEventRepository
 ) : MediatorUseCase<Pair<String?, SessionId>, LoadUserSessionUseCaseResult>() {
 
+    private var userSession: LiveData<Result<LoadUserSessionUseCaseResult>>? = null
+
     override fun execute(parameters: Pair<String?, SessionId>) {
         val (userId, eventId) = parameters
-        val userSession = userEventRepository.getObservableUserEvent(userId, eventId)
 
-        result.removeSource(userSession)
-        result.value = null
-        result.addSource(userSession) {
+        // Remove old data sources
+        clearSources()
+
+        // Fetch an observable of the data
+        val newUserSession = userEventRepository.getObservableUserEvent(userId, eventId)
+
+        // Post new values to the result object.
+        result.addSource(newUserSession) {
             DefaultScheduler.execute {
                 when (it) {
                     is Result.Success -> {
@@ -51,11 +58,19 @@ open class LoadUserSessionUseCase @Inject constructor(
                 }
             }
         }
+        // Save a reference to the observable for later cleaning of sources.
+        userSession = newUserSession
     }
 
     fun onCleared() {
-        // This use case is no longer going to be used so remove subscriptions
-        userEventRepository.clearSingleEventSubscriptions()
+        clearSources()
+    }
+
+    private fun clearSources() {
+        userSession?.let {
+            result.removeSource(it)
+        }
+        result.value = null
     }
 }
 

diff --git a/...in/java/com/google/samples/apps/iosched/shared/domain/sessions/LoadUserSessionsUseCase.kt b/...in/java/com/google/samples/apps/iosched/shared/domain/sessions/LoadUserSessionsUseCase.kt
@@ -22,7 +22,6 @@ import com.google.samples.apps.iosched.shared.domain.internal.DefaultScheduler
 import com.google.samples.apps.iosched.shared.model.SessionId
 import com.google.samples.apps.iosched.shared.model.UserSession
 import com.google.samples.apps.iosched.shared.result.Result
-import timber.log.Timber
 import javax.inject.Inject
 
 /**