Update

Made code more structured. Added 'scroll to VC at index'; added property 'initial view controller index' so that you can set the 'default' view controller or the view controller 'at start up'. (Something like the middle view controllers or the first view controller)
yichizhang · Nov 29, 2014 · d443cfa · d443cfa
1 parent 84d4dd7
commit d443cfa
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Showing 2 changed files with 106 additions and 40 deletions.
diff --git a/Source/YZSwipeBetweenViewController.h b/Source/YZSwipeBetweenViewController.h
@@ -16,8 +16,12 @@
 
 @interface YZSwipeBetweenViewController : UIViewController
 
-@property (strong) NSArray *viewControllers;
-@property (strong) UIScrollView *scrollView;
-@property (strong) UIView *overlayView;
+@property (nonatomic, strong) NSArray *viewControllers;
+@property (nonatomic, strong) UIScrollView *scrollView;
+@property (nonatomic, assign) int initialViewControllerIndex;
+
+- (void)reloadViewControllers;
+- (void)scrollToViewControllerAtIndex:(NSInteger)index;
+- (void)scrollToViewControllerAtIndex:(NSInteger)index animated:(BOOL)animated;
 
 @end
diff --git a/Source/YZSwipeBetweenViewController.m b/Source/YZSwipeBetweenViewController.m
@@ -23,43 +23,7 @@ @implementation YZSwipeBetweenViewController
 - (void)viewDidLoad {
     [super viewDidLoad];
     // Do any additional setup after loading the view.
-
-    CGRect mainScreenBounds = [[UIScreen mainScreen] bounds];
-
-    self.scrollView = [[UIScrollView alloc] initWithFrame:
-                       mainScreenBounds
-                       ];
-    CGFloat currentOriginX = 0;
-
-    for (UIViewController *vc in self.viewControllers) {
-        CGRect frame = vc.view.frame;
-        frame.origin.x = currentOriginX;
-        vc.view.frame = frame;
-
-        [self addChildViewController:vc];
-        [self.scrollView addSubview:vc.view];
-        [vc didMoveToParentViewController:self];
-
-        currentOriginX += mainScreenBounds.size.width;
-    }
-
-    //self.scrollView.backgroundColor = [UIColor colorWithWhite:0.9 alpha:1.0];
-    self.scrollView.contentSize =
-    CGSizeMake(
-               currentOriginX,
-               mainScreenBounds.size.height
-               );
-    self.scrollView.pagingEnabled = YES;
-    self.scrollView.showsHorizontalScrollIndicator = NO;
-    self.scrollView.showsVerticalScrollIndicator = NO;
-
-    self.scrollView.contentOffset =
-    CGPointMake(
-                (self.viewControllers.count/2) * mainScreenBounds.size.width,
-                0
-                );
-
-    [self.view addSubview:self.scrollView];
+	[self setupViewControllersForScrollView];
 
 }
 
@@ -68,6 +32,104 @@ - (void)didReceiveMemoryWarning {
     // Dispose of any resources that can be recreated.
 }
 
+#pragma mark - Private methods
+- (void)removeViewControllersFromScrollView{
+
+	for (UIViewController *vc in self.viewControllers) {
+
+		[vc willMoveToParentViewController:nil];
+		[vc.view removeFromSuperview];
+		[vc removeFromParentViewController];
+
+	}
+
+}
+
+- (void)addViewControllersToScrollView{
+
+	[self.scrollView removeFromSuperview];
+
+	CGRect mainScreenBounds = [[UIScreen mainScreen] bounds];
+
+	CGFloat currentOriginX = 0;
+
+	for (UIViewController *vc in self.viewControllers) {
+		CGRect frame = vc.view.frame;
+		frame.origin.x = currentOriginX;
+		vc.view.frame = frame;
+
+		[self addChildViewController:vc];
+		[self.scrollView addSubview:vc.view];
+		[vc didMoveToParentViewController:self];
+
+		currentOriginX += mainScreenBounds.size.width;
+	}
+
+	self.scrollView.contentSize =
+	CGSizeMake(
+			   currentOriginX,
+			   mainScreenBounds.size.height
+			   );
+	self.scrollView.pagingEnabled = YES;
+	self.scrollView.showsHorizontalScrollIndicator = NO;
+	self.scrollView.showsVerticalScrollIndicator = NO;
+
+	[self scrollToViewControllerAtIndex:self.initialViewControllerIndex];
+
+	[self.view addSubview:self.scrollView];
+
+}
+
+- (void)setupViewControllersForScrollView{
+
+	[self removeViewControllersFromScrollView];
+	[self addViewControllersToScrollView];
+
+}
+
+#pragma mark - Public Methods
+- (void)setViewControllers:(NSArray *)viewControllers{
+
+	_viewControllers = viewControllers;
+
+	[self setupViewControllersForScrollView];
+
+}
+
+- (void)reloadViewControllers{
+
+	[self setupViewControllersForScrollView];
+
+}
+
+- (void)scrollToViewControllerAtIndex:(NSInteger)index{
+
+	[self scrollToViewControllerAtIndex:index animated:NO];
+
+}
+
+- (void)scrollToViewControllerAtIndex:(NSInteger)index animated:(BOOL)animated{
+
+	if (index >= 0 && index < self.viewControllers.count) {
+		[self.scrollView
+		 scrollRectToVisible:[self.viewControllers[index] view].frame
+		 animated:YES
+		 ];
+	}
+
+}
+
+#pragma mark - Lazy loading of members
+- (UIScrollView *)scrollView{
+
+	if (!_scrollView) {
+		_scrollView = [[UIScrollView alloc] initWithFrame:
+					   [[UIScreen mainScreen] bounds]
+					   ];
+	}
+	return _scrollView;
+
+}
 /*
 #pragma mark - Navigation