Modify views to observe changes when active, not just foreground.

Signal/src/ViewControllers/ConversationView/ConversationViewController.m

@@ -233,7 +233,6 @@ typedef enum : NSUInteger {
 
 @property (nonatomic) BOOL isViewCompletelyAppeared;
 @property (nonatomic) BOOL isViewVisible;
-@property (nonatomic) BOOL isAppInBackground;
 @property (nonatomic) BOOL shouldObserveDBModifications;
 @property (nonatomic) BOOL viewHasEverAppeared;
 @property (nonatomic) BOOL hasUnreadMessages;
@@ -594,12 +593,12 @@ typedef enum : NSUInteger {
 - (void)applicationWillEnterForeground:(NSNotification *)notification
 {
     [self startReadTimer];
-    self.isAppInBackground = NO;
+    [self updateCellsVisible];
 }
 
 - (void)applicationDidEnterBackground:(NSNotification *)notification
 {
-    self.isAppInBackground = YES;
+    [self updateCellsVisible];
     if (self.hasClearedUnreadMessagesIndicator) {
         self.hasClearedUnreadMessagesIndicator = NO;
         [self.dynamicInteractions clearUnreadIndicatorState];
@@ -609,6 +608,7 @@ typedef enum : NSUInteger {
 
 - (void)applicationWillResignActive:(NSNotification *)notification
 {
+    [self updateShouldObserveDBModifications];
     [self cancelVoiceMemo];
     self.isUserScrolling = NO;
     [self saveDraft];
@@ -620,6 +620,7 @@ typedef enum : NSUInteger {
 
 - (void)applicationDidBecomeActive:(NSNotification *)notification
 {
+    [self updateShouldObserveDBModifications];
     [self startReadTimer];
 }
 
@@ -1530,7 +1531,8 @@ typedef enum : NSUInteger {
 
 - (void)autoLoadMoreIfNecessary
 {
-    if (self.isUserScrolling || !self.isViewVisible || self.isAppInBackground) {
+    BOOL isAppInBackground = CurrentAppContext().isInBackground;
+    if (self.isUserScrolling || !self.isViewVisible || isAppInBackground) {
         return;
     }
     if (!self.showLoadMoreHeader) {
@@ -4428,17 +4430,10 @@ typedef enum : NSUInteger {
     [self updateCellsVisible];
 }
 
-- (void)setIsAppInBackground:(BOOL)isAppInBackground
-{
-    _isAppInBackground = isAppInBackground;
-
-    [self updateShouldObserveDBModifications];
-    [self updateCellsVisible];
-}
-
 - (void)updateCellsVisible
 {
-    BOOL isCellVisible = self.isViewVisible && !self.isAppInBackground;
+    BOOL isAppInBackground = CurrentAppContext().isInBackground;
+    BOOL isCellVisible = self.isViewVisible && !isAppInBackground;
     for (ConversationViewCell *cell in self.collectionView.visibleCells) {
         cell.isCellVisible = isCellVisible;
     }
@@ -4446,7 +4441,8 @@ typedef enum : NSUInteger {
 
 - (void)updateShouldObserveDBModifications
 {
-    self.shouldObserveDBModifications = self.isViewVisible && !self.isAppInBackground;
+    BOOL isAppForegroundAndActive = CurrentAppContext().reportedApplicationState == UIApplicationStateActive;
+    self.shouldObserveDBModifications = self.isViewVisible && isAppForegroundAndActive;
 }
 
 - (void)setShouldObserveDBModifications:(BOOL)shouldObserveDBModifications

Signal/src/ViewControllers/HomeView/HomeViewController.m

@@ -51,7 +51,6 @@ NSString *const kArchivedConversationsReuseIdentifier = @"kArchivedConversations
 @property (nonatomic) NSSet<NSString *> *blockedPhoneNumberSet;
 @property (nonatomic, readonly) NSCache<NSString *, ThreadViewModel *> *threadViewModelCache;
 @property (nonatomic) BOOL isViewVisible;
-@property (nonatomic) BOOL isAppInBackground;
 @property (nonatomic) BOOL shouldObserveDBModifications;
 @property (nonatomic) BOOL hasBeenPresented;
 
@@ -131,14 +130,14 @@ NSString *const kArchivedConversationsReuseIdentifier = @"kArchivedConversations
                                              selector:@selector(applicationWillEnterForeground:)
                                                  name:OWSApplicationWillEnterForegroundNotification
                                                object:nil];
-    [[NSNotificationCenter defaultCenter] addObserver:self
-                                             selector:@selector(applicationDidEnterBackground:)
-                                                 name:OWSApplicationDidEnterBackgroundNotification
-                                               object:nil];
     [[NSNotificationCenter defaultCenter] addObserver:self
                                              selector:@selector(applicationDidBecomeActive:)
                                                  name:OWSApplicationDidBecomeActiveNotification
                                                object:nil];
+    [[NSNotificationCenter defaultCenter] addObserver:self
+                                             selector:@selector(applicationWillResignActive:)
+                                                 name:OWSApplicationWillResignActiveNotification
+                                               object:nil];
     [[NSNotificationCenter defaultCenter] addObserver:self
                                              selector:@selector(yapDatabaseModified:)
                                                  name:YapDatabaseModifiedNotification
@@ -484,16 +483,10 @@ NSString *const kArchivedConversationsReuseIdentifier = @"kArchivedConversations
     [self updateShouldObserveDBModifications];
 }
 
-- (void)setIsAppInBackground:(BOOL)isAppInBackground
-{
-    _isAppInBackground = isAppInBackground;
-
-    [self updateShouldObserveDBModifications];
-}
-
 - (void)updateShouldObserveDBModifications
 {
-    self.shouldObserveDBModifications = self.isViewVisible && !self.isAppInBackground;
+    BOOL isAppForegroundAndActive = CurrentAppContext().reportedApplicationState == UIApplicationStateActive;
+    self.shouldObserveDBModifications = self.isViewVisible && isAppForegroundAndActive;
 }
 
 - (void)setShouldObserveDBModifications:(BOOL)shouldObserveDBModifications
@@ -550,15 +543,9 @@ NSString *const kArchivedConversationsReuseIdentifier = @"kArchivedConversations
 
 - (void)applicationWillEnterForeground:(NSNotification *)notification
 {
-    self.isAppInBackground = NO;
     [self checkIfEmptyView];
 }
 
-- (void)applicationDidEnterBackground:(NSNotification *)notification
-{
-    self.isAppInBackground = YES;
-}
-
 - (BOOL)hasAnyMessagesWithTransaction:(YapDatabaseReadTransaction *)transaction
 {
     return [TSThread numberOfKeysInCollectionWithTransaction:transaction] > 0;
@@ -566,6 +553,8 @@ NSString *const kArchivedConversationsReuseIdentifier = @"kArchivedConversations
 
 - (void)applicationDidBecomeActive:(NSNotification *)notification
 {
+    [self updateShouldObserveDBModifications];
+
     // It's possible a thread was created while we where in the background. But since we don't honor contact
     // requests unless the app is in the foregrond, we must check again here upon becoming active.
     __block BOOL hasAnyMessages;
@@ -582,6 +571,11 @@ NSString *const kArchivedConversationsReuseIdentifier = @"kArchivedConversations
     }
 }
 
+- (void)applicationWillResignActive:(NSNotification *)notification
+{
+    [self updateShouldObserveDBModifications];
+}
+
 #pragma mark - startup
 
 - (NSArray<ExperienceUpgrade *> *)unseenUpgradeExperiences

SignalMessaging/Views/ThreadViewHelper.m

@@ -56,25 +56,31 @@ NS_ASSUME_NONNULL_BEGIN
     [self.uiDatabaseConnection beginLongLivedReadTransaction];
 
     [[NSNotificationCenter defaultCenter] addObserver:self
-                                             selector:@selector(applicationWillEnterForeground:)
-                                                 name:OWSApplicationWillEnterForegroundNotification
+                                             selector:@selector(applicationDidBecomeActive:)
+                                                 name:OWSApplicationDidBecomeActiveNotification
                                                object:nil];
     [[NSNotificationCenter defaultCenter] addObserver:self
-                                             selector:@selector(applicationDidEnterBackground:)
-                                                 name:OWSApplicationDidEnterBackgroundNotification
+                                             selector:@selector(applicationWillResignActive:)
+                                                 name:OWSApplicationWillResignActiveNotification
                                                object:nil];
 
-    self.shouldObserveDBModifications = !CurrentAppContext().isInBackground;
+    [self updateShouldObserveDBModifications];
 }
 
-- (void)applicationWillEnterForeground:(NSNotification *)notification
+- (void)applicationDidBecomeActive:(NSNotification *)notification
 {
-    self.shouldObserveDBModifications = YES;
+    [self updateShouldObserveDBModifications];
 }
 
-- (void)applicationDidEnterBackground:(NSNotification *)notification
+- (void)applicationWillResignActive:(NSNotification *)notification
 {
-    self.shouldObserveDBModifications = NO;
+    [self updateShouldObserveDBModifications];
+}
+
+- (void)updateShouldObserveDBModifications
+{
+    BOOL isAppForegroundAndActive = CurrentAppContext().reportedApplicationState == UIApplicationStateActive;
+    self.shouldObserveDBModifications = isAppForegroundAndActive;
 }
 
 // Don't observe database change notifications when the app is in the background.