NIPagingScrollView Class Reference

Overview

The NIPagingScrollView class provides a UITableView-like interface for loading pages via a data source.

Inheritance diagram for NIPagingScrollView:

Tasks
Data Source
id< NIPagingScrollViewDataSource >	dataSource property
id< NIPagingScrollViewDelegate >	delegate property
(void)	- reloadData
(UIView < NIPagingScrollViewPage > *)	- dequeueReusablePageWithIdentifier:
State
NSInteger	centerPageIndex property
NSInteger	numberOfPages property
(UIView < NIPagingScrollViewPage > *)	- centerPageView
Configuring Presentation
CGFloat	pageMargin property
NIPagingScrollViewType	type property
Changing the Visible Page
(BOOL)	- hasNext
(BOOL)	- hasPrevious
(void)	- moveToNextAnimated:
(void)	- moveToPreviousAnimated:
(BOOL)	- moveToPageAtIndex:animated:updateVisiblePagesWhileScrolling:
(BOOL)	- moveToPageAtIndex:animated:
Rotating the Scroll View
(void)	- willRotateToInterfaceOrientation:duration:
(void)	- willAnimateRotationToInterfaceOrientation:duration:

Method Documentation

dataSource

The data source for this page album view.

@property (nonatomic, weak) id<NIPagingScrollViewDataSource> dataSource;

Discussion

This is the only means by which this paging view acquires any information about the album to be displayed.

delegate

The delegate for this paging view.

@property (nonatomic, weak) id<NIPagingScrollViewDelegate> delegate;

Discussion

Any user interactions or state changes are sent to the delegate through this property.

centerPageIndex

The current center page index.

@property (nonatomic) NSInteger centerPageIndex;

Discussion

This is a zero-based value. If you intend to use this in a label such as "page ## of n" be sure to add one to this value.

Setting this value directly will center the new page without any animation.

numberOfPages

The total number of pages in this paging view, as gathered from the data source.

@property (nonatomic, readonly) NSInteger numberOfPages;

Discussion

This value is cached after reloadData has been called.

Until reloadData is called the first time, numberOfPages will be NIPagingScrollViewUnknownNumberOfPages.

pageMargin

The number of pixels on either side of each page.

@property (nonatomic) CGFloat pageMargin;

Discussion

The space between each page will be 2x this value.

By default this is NIPagingScrollViewDefaultPageMargin.

type

The type of paging scroll view to display.

@property (nonatomic) NIPagingScrollViewType type;

Discussion

This property allows you to configure whether you want a horizontal or vertical paging scroll view. You should set this property before you present the scroll view and not modify it after.

By default this is NIPagingScrollViewHorizontal.

reloadData

Force the view to reload its data by asking the data source for information.

- (void)reloadData;

Discussion

This must be called at least once after dataSource has been set in order for the view to gather any presentable information.

This method is cheap because we only fetch new information about the currently displayed pages. If the number of pages shrinks then the current center page index will be decreased accordingly.

dequeueReusablePageWithIdentifier:

Dequeues a reusable page from the set of recycled pages.

- (UIView<NIPagingScrollViewPage>*)dequeueReusablePageWithIdentifier:(NSString *)identifier;

Discussion

If no pages have been recycled for the given identifier then this will return nil. In this case it is your responsibility to create a new page.

centerPageView

The current center page view.

- (UIView<NIPagingScrollViewPage>*)centerPageView;

Discussion

If no pages exist then this will return nil.

hasNext

Returns YES if there is a next page.

- (BOOL)hasNext;

hasPrevious

Returns YES if there is a previous page.

- (BOOL)hasPrevious;

moveToNextAnimated:

Move to the next page if there is one.

- (void)moveToNextAnimated:(BOOL)animated;

moveToPreviousAnimated:

Move to the previous page if there is one.

- (void)moveToPreviousAnimated:(BOOL)animated;

moveToPageAtIndex:animated:updateVisiblePagesWhileScrolling:

Move to the given page index with optional animation and option to enable page updates while scrolling.

- (BOOL)moveToPageAtIndex:(NSInteger)pageIndex animated:(BOOL)animated updateVisiblePagesWhileScrolling:(BOOL)updateVisiblePagesWhileScrolling;

Discussion

NOTE: Passing YES for moveToPageAtIndex:animated:updateVisiblePagesWhileScrolling will cause every page from the present page to the destination page to be loaded. This has the potential to cause choppy animations.

Parameters

updateVisiblePagesWhileScrolling

If YES, will query the data source for any pages that become visible while the animation occurs.

Returns

NO if a page change animation is already in effect and we couldn't change the page again.

moveToPageAtIndex:animated:

Move to the given page index with optional animation.

- (BOOL)moveToPageAtIndex:(NSInteger)pageIndex animated:(BOOL)animated;

Discussion

Returns

NO if a page change animation is already in effect and we couldn't change the page again.

willRotateToInterfaceOrientation:duration:

Stores the current state of the scroll view in preparation for rotation.

- (void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration;

Discussion

This must be called in conjunction with willAnimateRotationToInterfaceOrientation:duration: in the methods by the same name from the view controller containing this view.

willAnimateRotationToInterfaceOrientation:duration:

Updates the frame of the scroll view while maintaining the current visible page's state.

- (void)willAnimateRotationToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration;