BUGFIX: fixed view controller handling (issue 6)

Author: weissi

FRLayeredNavigationController/FRLayerController.h

@@ -39,6 +39,7 @@
 
     FRLayerChromeView *_chromeView;
     UIView *_borderView;
+    UIView __weak *_contentView;
 
     UIViewController *_contentViewController;
 }

FRLayeredNavigationController/FRLayerController.m

@@ -43,6 +43,7 @@ @interface FRLayerController ()
 
 @property (nonatomic, strong) FRLayerChromeView *chromeView;
 @property (nonatomic, strong) UIView *borderView;
+@property (nonatomic, weak) UIView *contentView;
 
 @end
 
@@ -56,8 +57,6 @@ - (id)initWithContentViewController:(UIViewController *)vc maximumWidth:(BOOL)ma
         _layeredNavigationItem.layerController = self;
         _contentViewController = vc;
         _maximumWidth = maxWidth;
-
-        [self attachContentViewController];
     }
 
     return self;
@@ -66,12 +65,10 @@ - (id)initWithContentViewController:(UIViewController *)vc maximumWidth:(BOOL)ma
 - (void)dealloc
 {
     self.layeredNavigationItem.layerController = nil;
-    [self detachContentViewController];
 }
 
 #pragma mark - internal methods
 
-
 - (void)doViewLayout {
     CGRect contentFrame = CGRectZero;
 
@@ -98,20 +95,9 @@ - (void)doViewLayout {
     }
 
 
-    self.contentViewController.view.frame = contentFrame;
+    self.contentView.frame = contentFrame;
 }
 
-- (void)attachContentViewController
-{
-    [self addChildViewController:self.contentViewController];
-    [self.contentViewController didMoveToParentViewController:self];
-}
-
-- (void)detachContentViewController
-{
-    [self.contentViewController willMoveToParentViewController:nil];
-    [self.contentViewController removeFromParentViewController];
-}
 
 #pragma mark - UIViewController interface methods
 
@@ -133,7 +119,15 @@ - (void)loadView {
         [self.view addSubview:self.chromeView];
         [self.view addSubview:self.borderView];
     }
-    [self.view addSubview:self.contentViewController.view];
+
+    if (self.contentView == nil && self.contentViewController.parentViewController == self) {
+        /* when loaded again after a low memory view removal */
+        self.contentView = self.contentViewController.view;
+    }
+
+    if (self.contentView != nil) {
+        [self.view addSubview:self.contentView];
+    }
 }
 
 - (void)viewWillLayoutSubviews {
@@ -155,17 +149,51 @@ - (void)viewDidUnload
 
     self.borderView = nil;
     self.chromeView = nil;
+    self.contentView = nil;
 }
 
 - (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
 {
 	return YES;
 }
 
+- (void)willMoveToParentViewController:(UIViewController *)parent
+{
+    [super willMoveToParentViewController:parent];
+
+    if (parent != nil) {
+        /* will shortly attach to parent */
+        [self addChildViewController:self.contentViewController];
+
+        self.contentView = self.contentViewController.view;
+        [self.view addSubview:self.contentView];
+    } else {
+        /* will shortly detach from parent view controller */
+        [self.contentViewController willMoveToParentViewController:nil];
+
+        [self.contentView removeFromSuperview];
+        self.contentView = nil;
+    }
+}
+
+- (void)didMoveToParentViewController:(UIViewController *)parent
+{
+    [super didMoveToParentViewController:parent];
+
+    if (parent != nil) {
+        /* just attached to parent view controller */
+        [self.contentViewController didMoveToParentViewController:self];
+    } else {
+        /* did just detach */
+        [self.contentViewController removeFromParentViewController];
+    }
+}
+
 @synthesize contentViewController = _contentViewController;
 @synthesize maximumWidth = _maximumWidth;
 @synthesize borderView = _borderView;
 @synthesize chromeView = _chromeView;
 @synthesize layeredNavigationItem = _layeredNavigationItem;
+@synthesize contentView = _contentView;
 
 @end

FRLayeredNavigationController/FRLayeredNavigationController.m

@@ -500,20 +500,32 @@ - (void)popViewControllerAnimated:(BOOL)animated
         return;
     }
 
-    [vc willMoveToParentViewController:nil];
     [self.viewControllers removeObject:vc];
 
-    CGRect goAwayFrame = CGRectMake(vc.view.frame.origin.x, 1024, vc.view.bounds.size.width, vc.view.bounds.size.height);
-    [UIView animateWithDuration:animated ? 0.5 : 0
-                          delay:0
-                        options: UIViewAnimationCurveLinear
-                     animations:^{
-                         vc.view.frame = goAwayFrame;
-                     }
-                     completion:^(BOOL finished) {
-                         [vc.view removeFromSuperview];
-                         [vc removeFromParentViewController];
-                     }];
+    CGRect goAwayFrame = CGRectMake(vc.view.frame.origin.x,
+                                    1024,
+                                    vc.view.bounds.size.width,
+                                    vc.view.bounds.size.height);
+
+    void (^completeViewRemoval)(BOOL) = ^(BOOL finished) {
+        [vc willMoveToParentViewController:nil];
+
+        [vc.view removeFromSuperview];
+
+        [vc removeFromParentViewController];
+    };
+
+    if (animated) {
+        [UIView animateWithDuration:0.5
+                              delay:0
+                            options: UIViewAnimationCurveLinear
+                         animations:^{
+                             vc.view.frame = goAwayFrame;
+                         }
+                         completion:completeViewRemoval];
+    } else {
+        completeViewRemoval(YES);
+    }
 }
 
 - (void)popToViewController:(UIViewController *)vc animated:(BOOL)animated
@@ -556,7 +568,12 @@ - (void)pushViewController:(UIViewController *)contentViewController
                                  self.view.bounds.size.width :
                                  [self getScreenBoundsForCurrentOrientation].size.width;
 
-    [self popToViewController:anchorViewController animated:animated];
+    if (contentViewController.parentViewController.parentViewController == self) {
+        /* no animation if the new content view controller is already a child of self */
+        [self popToViewController:anchorViewController animated:NO];
+    } else {
+        [self popToViewController:anchorViewController animated:animated];
+    }
 
     CGFloat anchorInitX = anchorViewController.layeredNavigationItem.initialViewPosition.x;
     CGFloat anchorCurrentX = anchorViewController.layeredNavigationItem.currentViewPosition.x;
@@ -594,7 +611,6 @@ - (void)pushViewController:(UIViewController *)contentViewController
     [self.viewControllers addObject:newVC];
     [self addChildViewController:newVC];
     [self.view addSubview:newVC.view];
-    [newVC didMoveToParentViewController:self];
 
     [UIView animateWithDuration:animated ? 0.5 : 0
                           delay:0
@@ -609,6 +625,7 @@ - (void)pushViewController:(UIViewController *)contentViewController
 
                      }
                      completion:^(BOOL finished) {
+                         [newVC didMoveToParentViewController:self];
                      }];
 }