From c1dbf407be8ca0877c00a0ee95622605405dbfe9 Mon Sep 17 00:00:00 2001
From: Mattt Thompson <m@mattt.me>
Date: Thu, 6 Oct 2011 10:43:48 -0500
Subject: [PATCH] [Issue #65] Adding slight delay when hiding network activity
 indicator, to avoid flickering

---
 .../AFNetworkActivityIndicatorManager.h       |  1 +
 .../AFNetworkActivityIndicatorManager.m       | 30 +++++++++++++++++--
 2 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/AFNetworking/AFNetworkActivityIndicatorManager.h b/AFNetworking/AFNetworkActivityIndicatorManager.h
index 4cd8908..9df6098 100644
--- a/AFNetworking/AFNetworkActivityIndicatorManager.h
+++ b/AFNetworking/AFNetworkActivityIndicatorManager.h
@@ -29,6 +29,7 @@
 @private
 	NSInteger _activityCount;
     BOOL _enabled;
+    NSTimer *_activityIndicatorVisibilityTimer;
 }
 
 /**
diff --git a/AFNetworking/AFNetworkActivityIndicatorManager.m b/AFNetworking/AFNetworkActivityIndicatorManager.m
index 7094ea6..f24b7c0 100644
--- a/AFNetworking/AFNetworkActivityIndicatorManager.m
+++ b/AFNetworking/AFNetworkActivityIndicatorManager.m
@@ -24,13 +24,21 @@
 
 #import "AFHTTPRequestOperation.h"
 
+static NSTimeInterval const kAFNetworkActivityIndicatorInvisibilityDelay = 0.25;
+
 @interface AFNetworkActivityIndicatorManager ()
 @property (readwrite, nonatomic, assign) NSInteger activityCount;
+@property (readwrite, nonatomic, retain) NSTimer *activityIndicatorVisibilityTimer;
+@property (readonly, getter = isNetworkActivityIndicatorVisible) BOOL networkActivityIndicatorVisible;
+
+- (void)updateNetworkActivityIndicatorVisibility;
 @end
 
 @implementation AFNetworkActivityIndicatorManager
 @synthesize activityCount = _activityCount;
+@synthesize activityIndicatorVisibilityTimer = _activityIndicatorVisibilityTimer;
 @synthesize enabled = _enabled;
+@dynamic networkActivityIndicatorVisible;
 
 + (AFNetworkActivityIndicatorManager *)sharedManager {
     static AFNetworkActivityIndicatorManager *_sharedManager = nil;
@@ -50,13 +58,16 @@
 
     [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(incrementActivityCount) name:AFNetworkingOperationDidStartNotification object:nil];
     [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(decrementActivityCount) name:AFNetworkingOperationDidFinishNotification object:nil];
-    
+        
     return self;
 }
 
 - (void)dealloc {
     [[NSNotificationCenter defaultCenter] removeObserver:self];
     
+    [_activityIndicatorVisibilityTimer invalidate];
+    [_activityIndicatorVisibilityTimer release]; _activityIndicatorVisibilityTimer = nil;
+    
     [super dealloc];
 }
 
@@ -66,10 +77,25 @@
     [self didChangeValueForKey:@"activityCount"];
 
     if (self.enabled) {
-        [[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:self.activityCount > 0];
+        // Delay hiding of activity indicator for a short interval, to avoid flickering
+        if (![self isNetworkActivityIndicatorVisible]) {
+            [self.activityIndicatorVisibilityTimer invalidate];
+            self.activityIndicatorVisibilityTimer = [NSTimer timerWithTimeInterval:kAFNetworkActivityIndicatorInvisibilityDelay target:self selector:@selector(updateNetworkActivityIndicatorVisibility) userInfo:nil repeats:NO];
+            [[NSRunLoop currentRunLoop] addTimer:self.activityIndicatorVisibilityTimer forMode:NSRunLoopCommonModes];
+        } else {
+            [self updateNetworkActivityIndicatorVisibility];
+        }
     }
 }
 
+- (BOOL)isNetworkActivityIndicatorVisible {
+    return self.activityCount > 0;
+}
+
+- (void)updateNetworkActivityIndicatorVisibility {
+    [[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:[self isNetworkActivityIndicatorVisible]];
+}
+
 - (void)incrementActivityCount {
     @synchronized(self) {
         self.activityCount += 1;