Add ability to stick extension view to the top.

TLYShyNavBar/TLYShyNavBarManager.h

@@ -42,6 +42,10 @@
  */
 @property (nonatomic, readonly) CGRect extensionViewBounds;
 
+/* Sticky extension view
+ */
+@property (nonatomic) BOOL stickyExtensionView;
+
 /* Control the resistance when scrolling up/down before the navbar 
  * expands/contracts again.
  */

TLYShyNavBar/TLYShyNavBarManager.m

@@ -210,6 +210,15 @@ static inline CGFloat AACStatusBarHeight()
     }
 }
 
+- (void)setStickyExtensionView:(BOOL)stickyExtensionView
+{
+    _stickyExtensionView = stickyExtensionView;
+    
+    if (self.navBarController) {
+        self.navBarController.stickyExtensionView = YES;
+    }
+}
+
 #pragma mark - Private methods
 
 - (BOOL)_shouldHandleScrolling

TLYShyNavBar/TLYShyViewController.h

@@ -40,6 +40,10 @@ typedef CGFloat(^TLYShyViewControllerContractionAmountBlock)(UIView *view);
 
 @property (nonatomic, readonly) CGFloat totalHeight;
 
+/* Sticky extension view
+ */
+@property (nonatomic) BOOL stickyExtensionView;
+
 - (CGFloat)updateYOffset:(CGFloat)deltaY;
 
 - (CGFloat)snap:(BOOL)contract;

TLYShyNavBar/TLYShyViewController.m

@@ -89,7 +89,7 @@ const CGFloat contractionVelocity = 300.f;
 
 - (CGFloat)updateYOffset:(CGFloat)deltaY
 {
-    if (self.child && deltaY < 0)
+    if (self.child && deltaY < 0 && !self.stickyExtensionView)
     {
         deltaY = [self.child updateYOffset:deltaY];
         self.child.view.hidden = (deltaY) < 0;
@@ -100,6 +100,12 @@ const CGFloat contractionVelocity = 300.f;
     
     self.view.center = CGPointMake(self.expandedCenterValue.x, newYCenter);
     
+    if (self.stickyExtensionView) {
+        CGFloat newChildYOffset = self.child.view.center.y + deltaY;
+        CGFloat newChildYCenter = MAX(MIN(self.child.expandedCenterValue.y, newChildYOffset), self.child.contractedCenterValue.y);
+        self.child.view.center = CGPointMake(self.child.expandedCenterValue.x, newChildYCenter);
+    }
+    
     if (self.hidesSubviews)
     {
         CGFloat newAlpha = 1.f - (self.expandedCenterValue.y - self.view.center.y) / self.contractionAmountValue;
@@ -113,7 +119,7 @@ const CGFloat contractionVelocity = 300.f;
     
     CGFloat residual = newYOffset - newYCenter;
     
-    if (self.child && deltaY > 0 && residual > 0)
+    if (self.child && deltaY > 0 && residual > 0 && !self.stickyExtensionView)
     {
         residual = [self.child updateYOffset:residual];
         self.child.view.hidden = residual - (newYOffset - newYCenter) > FLT_EPSILON;

TLYShyNavBarDemo/TLYShyNavBarDemo/TLYViewController.m

@@ -37,6 +37,8 @@
     self.shyNavBarManager.scrollView = self.scrollView;
     /* Can then be remove by setting the ExtensionView to nil */
     [self.shyNavBarManager setExtensionView:view];
+    /* Make the extension view stick to the top */
+    [self.shyNavBarManager setStickyExtensionView:YES];
 }
 
 - (void)viewDidLayoutSubviews