[BUGFIX lxcid#80] Clean up gestures when collectionView property is nil'ed or layout is deallocated.

Author: lxcid

LXRCVFL Example using Storyboard/LXRCVFL Example using Storyboard/LXCollectionViewController.m

@@ -9,7 +9,6 @@
 #import "LXCollectionViewController.h"
 #import "PlayingCard.h"
 #import "PlayingCardCell.h"
-#import "LXReorderableCollectionViewFlowLayout.h"
 
 // LX_LIMITED_MOVEMENT:
 // 0 = Any card can move anywhere
@@ -21,8 +20,6 @@ @implementation LXCollectionViewController
 
 - (void)viewDidLoad {
     [super viewDidLoad];
-//    self.collectionView.collectionViewLayout = [LXReorderableCollectionViewFlowLayout new];
-//    self.collectionView.collectionViewLayout = [LXReorderableCollectionViewFlowLayout new];
 
     self.deck = [self constructsDeck];
 }

LXReorderableCollectionViewFlowLayout/LXReorderableCollectionViewFlowLayout.m

@@ -107,6 +107,30 @@ - (void)setupCollectionView {
     [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(handleApplicationWillResignActive:) name: UIApplicationWillResignActiveNotification object:nil];
 }
 
+- (void)tearDownCollectionView {
+    // Tear down long press gesture
+    if (_longPressGestureRecognizer) {
+        UIView *view = _longPressGestureRecognizer.view;
+        if (view) {
+            [view removeGestureRecognizer:_longPressGestureRecognizer];
+        }
+        _longPressGestureRecognizer.delegate = nil;
+        _longPressGestureRecognizer = nil;
+    }
+    
+    // Tear down pan gesture
+    if (_panGestureRecognizer) {
+        UIView *view = _panGestureRecognizer.view;
+        if (view) {
+            [view removeGestureRecognizer:_panGestureRecognizer];
+        }
+        _panGestureRecognizer.delegate = nil;
+        _panGestureRecognizer = nil;
+    }
+    
+    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIApplicationWillResignActiveNotification object:nil];
+}
+
 - (id)init {
     self = [super init];
     if (self) {
@@ -126,13 +150,9 @@ - (id)initWithCoder:(NSCoder *)aDecoder {
 }
 
 - (void)dealloc {
-
-    [self.panGestureRecognizer.view removeGestureRecognizer:self.panGestureRecognizer];
-    [self.longPressGestureRecognizer.view removeGestureRecognizer:self.longPressGestureRecognizer];
-    
     [self invalidatesScrollTimer];
+    [self tearDownCollectionView];
     [self removeObserver:self forKeyPath:kLXCollectionViewKeyPath];
-    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIApplicationWillResignActiveNotification object:nil];
 }
 
 - (void)applyLayoutAttributes:(UICollectionViewLayoutAttributes *)layoutAttributes {
@@ -494,6 +514,7 @@ - (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(N
             [self setupCollectionView];
         } else {
             [self invalidatesScrollTimer];
+            [self tearDownCollectionView];
         }
     }
 }