[WIP] Fixes issues with the arrangedSubviews property

Pod/Classes/OAStackView+Constraint.m

@@ -21,8 +21,7 @@ - (NSArray*)constraintsBetweenView:(UIView*)firstView andView:(UIView*)otherView
       viewMatches = viewMatches || (firstView == constraint.secondItem && otherView == constraint.firstItem);
     }
 
-    BOOL isCorrectAxis = [self isConstraintAttribute:constraint.firstAttribute affectingAxis:axis] ||
-    [self isConstraintAttribute:constraint.secondAttribute affectingAxis:axis];
+    BOOL isCorrectAxis = [self isConstraint:constraint affectingAxis:axis];
 
     if (viewMatches && isCorrectAxis) {
       [arr addObject:constraint];
@@ -141,15 +140,29 @@ - (BOOL)isConstraintAttribute:(NSLayoutAttribute)attribute affectingAxis:(UILayo
     case UILayoutConstraintAxisHorizontal:
       return attribute == NSLayoutAttributeLeft || attribute == NSLayoutAttributeRight ||
       attribute == NSLayoutAttributeLeading || attribute == NSLayoutAttributeTrailing ||
-      attribute == NSLayoutAttributeCenterX || attribute == NSLayoutAttributeWidth;
+      attribute == NSLayoutAttributeCenterX || attribute == NSLayoutAttributeWidth
+#if __IPHONE_OS_VERSION_MAX_ALLOWED > __IPHONE_7_1
+      || attribute == NSLayoutAttributeLeftMargin || attribute == NSLayoutAttributeRightMargin ||
+      attribute == NSLayoutAttributeLeadingMargin || attribute == NSLayoutAttributeTrailingMargin ||
+      attribute == NSLayoutAttributeCenterXWithinMargins
+#endif
+      ;
       break;
 
     case UILayoutConstraintAxisVertical:
       return attribute == NSLayoutAttributeTop || attribute == NSLayoutAttributeBottom ||
-      attribute == NSLayoutAttributeCenterY || attribute == NSLayoutAttributeHeight;
+      attribute == NSLayoutAttributeCenterY || attribute == NSLayoutAttributeHeight ||
+      attribute == NSLayoutAttributeBaseline
+#if __IPHONE_OS_VERSION_MAX_ALLOWED > __IPHONE_7_1
+      || attribute == NSLayoutAttributeLastBaseline || attribute == NSLayoutAttributeFirstBaseline ||
+      attribute == NSLayoutAttributeTopMargin || attribute == NSLayoutAttributeBottomMargin ||
+      attribute == NSLayoutAttributeCenterYWithinMargins
+#endif
+      ;
       break;
 
     default:
+      return NO;
       break;
   }
 }

Pod/Classes/OAStackView+Hiding.m

@@ -51,16 +51,4 @@ - (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(N
 
 }
 
-#pragma mark subviews
-
-- (void)didAddSubview:(UIView *)subview {
-  [super didAddSubview:subview];
-  [self addObserverForView:subview];
-}
-
-- (void)willRemoveSubview:(UIView *)subview {
-  [super willRemoveSubview:subview];
-  [self removeObserverForView:subview];
-}
-
 @end

Pod/Classes/OAStackView+Traversal.h

@@ -10,15 +10,13 @@
 
 @interface OAStackView (Traversal)
 
-- (UIView*)visibleViewBeforeIndex:(NSInteger)index;
-- (UIView*)visibleViewBeforeView:(UIView*)view;
+- (UIView*)arrangedSubviewBeforeIndex:(NSInteger)index;
+- (UIView*)arrangedSubviewBeforeView:(UIView*)view;
 
-- (UIView*)visibleViewAfterIndex:(NSInteger)index;
-- (UIView*)visibleViewAfterView:(UIView*)view;
+- (UIView*)arrangedSubviewAfterIndex:(NSInteger)index;
+- (UIView*)arrangedSubviewAfterView:(UIView*)view;
 
-- (void)iterateVisibleViews:(void (^) (UIView *view, UIView *previousView))block;
-
-- (UIView*)lastVisibleItem;
+- (void)iterateArrangedSubviews:(void (^) (UIView *view, UIView *previousView))block;
 
 - (NSLayoutConstraint*)firstViewConstraint;
 - (NSLayoutConstraint*)lastViewConstraint;

Pod/Classes/OAStackView+Traversal.m

@@ -7,72 +7,50 @@
 //
 
 #import "OAStackView+Traversal.h"
+#import "OAStackView_ArrangedSubviews.h"
 
 @implementation OAStackView (Traversal)
 
-- (UIView*)visibleViewBeforeView:(UIView*)view {
-  NSInteger index = [self.subviews indexOfObject:view];
+- (UIView*)arrangedSubviewBeforeView:(UIView*)view {
+  NSInteger index = [self indexInArrangedSubviewsOfObject:view];
   if (index == NSNotFound) { return nil; }
 
-  return [self visibleViewBeforeIndex:index];
+  return [self arrangedSubviewBeforeIndex:index];
 }
 
-- (UIView*)visibleViewAfterView:(UIView*)view {
-  NSInteger index = [self.subviews indexOfObject:view];
+- (UIView*)arrangedSubviewAfterView:(UIView*)view {
+  NSInteger index = [self indexInArrangedSubviewsOfObject:view];
   if (index == NSNotFound) { return nil; }
 
-  return [self visibleViewAfterIndex:index];
+  return [self arrangedSubviewAfterIndex:index];
 }
 
-- (UIView*)visibleViewAfterIndex:(NSInteger)index {
-  for (NSInteger i = index + 1; i < self.subviews.count; i++) {
-    UIView *theView = self.subviews[i];
-    if (!theView.hidden) {
-      return theView;
-    }
+- (UIView*)arrangedSubviewAfterIndex:(NSInteger)index {
+  if ((index + 1) < [self countOfArrangedSubviews]) {
+    return [self objectInArrangedSubviewsAtIndex:index+1];
   }
 
   return nil;
 }
 
-- (UIView*)visibleViewBeforeIndex:(NSInteger)index {
-  for (NSInteger i = index - 1; i >= 0; i--) {
-    UIView *theView = self.subviews[i];
-    if (!theView.hidden) {
-      return theView;
-    }
+- (UIView*)arrangedSubviewBeforeIndex:(NSInteger)index {
+  if (index > 0) {
+    return [self objectInArrangedSubviewsAtIndex:index-1];
   }
 
   return nil;
 }
 
-- (UIView*)lastVisibleItem {
-  return [self visibleViewBeforeIndex:self.subviews.count];
-}
-
-- (void)iterateVisibleViews:(void (^) (UIView *view, UIView *previousView))block {
-
-  id previousView;
-  for (UIView *view in self.subviews) {
-    if (view.isHidden) { continue; }
+- (void)iterateArrangedSubviews:(void (^) (UIView *view, UIView *previousView))block {
+  UIView *previousView = nil;
+  for (NSUInteger i = 0; i < [self countOfArrangedSubviews]; i++) {
+    UIView *view = [self objectInArrangedSubviewsAtIndex:i];
 
     block(view, previousView);
     previousView = view;
   }
 }
 
-- (NSArray*)currentVisibleViews {
-  NSMutableArray *arr = [@[] mutableCopy];
-  [self iterateVisibleViews:^(UIView *view, UIView *previousView) {
-    [arr addObject:view];
-  }];
-  return arr;
-}
-
-- (BOOL)isLastVisibleItem:(UIView*)view {
-  return view == [self lastVisibleItem];
-}
-
 - (NSLayoutConstraint*)lastViewConstraint {
   for (NSLayoutConstraint *constraint in self.constraints) {
 
@@ -113,7 +91,7 @@ - (NSLayoutConstraint*)firstViewConstraint {
 }
 
 - (BOOL)isViewLastItem:(UIView*)view excludingItem:(UIView*)excludingItem {
-  NSArray *visible = [self currentVisibleViews];
+  NSArray *visible = [self arrangedSubviews];
   NSInteger index = [visible indexOfObject:view];
   NSInteger exclutedIndex = [visible indexOfObject:excludingItem];
 

Pod/Classes/OAStackView.h

@@ -76,13 +76,16 @@ typedef NS_ENUM(NSInteger, OAStackViewAlignment) {
 #define NS_ASSUME_NONNULL_BEGIN
 #define NS_ASSUME_NONNULL_END
 #define nullable
-#define nonnullable
+#define nonnull
 #define __nullable
+#define __nonnull
 #endif
 
 NS_ASSUME_NONNULL_BEGIN
 @interface OAStackView : UIView
 
+// The views that are currently being arranged.
+// Views that are hidden will be removed from this list
 @property(nonatomic,readonly,copy) NSArray *arrangedSubviews;
 
 //Default is Vertical