#42 Small tweaks to the initial page implementation

Author: stefanceriu

Demo/ObjCDemo/SCRootViewController.m

@@ -52,6 +52,8 @@ - (void)viewDidLoad
 	[self.pageViewController.view setFrame:self.view.bounds];
 	[self.view addSubview:self.pageViewController.view];
 	[self.pageViewController didMoveToParentViewController:self];
+    
+    [self _updateViewControllerDetails];
 }
 
 #pragma mark - SCPageViewControllerDataSource
@@ -77,6 +79,11 @@ - (UIViewController *)pageViewController:(SCPageViewController *)pageViewControl
 	return viewController;
 }
 
+- (NSUInteger)initialPageInPageViewController:(SCPageViewController *)pageViewController
+{
+    return 4;
+}
+
 #pragma mark - SCPageViewControllerDelegate
 
 - (void)pageViewController:(SCPageViewController *)pageViewController didNavigateToOffset:(CGPoint)offset

README.md

@@ -43,12 +43,13 @@ SCPageViewController relies on page layouters to know where to place each of the
     [self.pageViewController setLayouter:[[SCPageLayouter alloc] init] animated:NO completion:nil];
 ```
 
-- Implement the SCPageViewControllerDataSource which defines the total number of pages and the view controllers to be used for each of them.
+- Implement the SCPageViewControllerDataSource to define the total number of pages, the view controllers to be used for each of them and which one show be displayed first.
 
 ```objc
 - (NSUInteger)numberOfPagesInPageViewController:(SCPageViewController *)pageViewController;
 
 - (UIViewController *)pageViewController:(SCPageViewController *)pageViewController viewControllerForPageAtIndex:(NSUInteger)pageIndex;
+
 - (NSUInteger)initialPageInPageViewController:(SCPageViewController *)pageViewController;
 ```
 

SCPageViewController/SCPageViewController.h

@@ -215,7 +215,7 @@
 
 /**
  * @param pageViewController The calling PageViewController
- * @return The initial page that should be load. Otherwise the first is chosen.
+ * @return The initial page that should be loaded, otherwise the first is chosen.
  */
 @optional
 - (NSUInteger)initialPageInPageViewController:(SCPageViewController *)pageViewController;

SCPageViewController/SCPageViewController.m

@@ -42,9 +42,6 @@ @interface SCPageViewController () <SCPageViewControllerViewDelegate, UIScrollVi
 
 @property (nonatomic, assign) NSUInteger currentPage;
 
-@property (nonatomic, assign) NSUInteger initialPage;
-@property (nonatomic, assign) BOOL finishedLoadingInitialPage;
-
 @property (nonatomic, strong) NSMutableArray *visibleControllers;
 
 @property (nonatomic, assign) BOOL isContentOffsetBlocked;
@@ -60,6 +57,8 @@ @interface SCPageViewController () <SCPageViewControllerViewDelegate, UIScrollVi
 
 @property (nonatomic, strong) NSIndexSet *insertionIndexes;
 
+@property (nonatomic, strong) NSNumber *initialPageIndex;
+
 @end
 
 @implementation SCPageViewController
@@ -129,21 +128,19 @@ - (void)viewDidLoad
     [scrollViewWrapper addSubview:self.scrollView];
 
 	[self.view addSubview:scrollViewWrapper];
-
-	if([self.dataSource respondsToSelector:@selector(initialPageInPageViewController:)]) {
-		self.initialPage = [self.dataSource initialPageInPageViewController:self];
-		self.currentPage = self.initialPage;
-		self.finishedLoadingInitialPage = false;
-	} else {
-        self.finishedLoadingInitialPage = true;
-	}
-
+    
+    if([self.dataSource respondsToSelector:@selector(initialPageInPageViewController:)]) {
+        self.initialPageIndex = @([self.dataSource initialPageInPageViewController:self]);
+        self.currentPage = self.initialPageIndex.unsignedIntegerValue;
+    }
+    
 	[self reloadData];
 }
 
 - (void)viewWillLayoutSubviews
 {
 	[super viewWillLayoutSubviews];
+    
 	[self setLayouter:self.layouter andFocusOnIndex:self.currentPage animated:NO completion:nil];
 }
 
@@ -155,6 +152,13 @@ - (void)viewWillAppear:(BOOL)animated
 	[self _tilePages];
 }
 
+- (void)viewDidAppear:(BOOL)animated
+{
+    [super viewDidAppear:animated];
+    
+    self.initialPageIndex = nil;
+}
+
 - (void)viewDidDisappear:(BOOL)animated
 {
 	[super viewDidDisappear:animated];
@@ -287,10 +291,6 @@ - (void)navigateToPageAtIndex:(NSUInteger)pageIndex
 		if(completion) {
 			completion();
 		}
-
-        if(!self.finishedLoadingInitialPage &&  pageIndex == self.initialPage) {
-            self.finishedLoadingInitialPage = true;
-        }
 	};
 
 	[self.scrollView setContentOffset:offset easingFunction:self.easingFunction duration:(animated ? self.animationDuration : 0.0f) completion:animationFinishedBlock];
@@ -472,9 +472,9 @@ - (void)_tilePages
 		return;
 	}
 
-	if(self.finishedLoadingInitialPage) {
-		self.currentPage = [self _calculateCurrentPage];
-	}
+    if(!self.initialPageIndex) {
+        self.currentPage = [self _calculateCurrentPage];
+    }
 
 	NSInteger firstNeededPageIndex = self.currentPage - [self.layouter numberOfPagesToPreloadBeforeCurrentPage];
 	firstNeededPageIndex = MAX(firstNeededPageIndex, 0);