iOS模仿电子书首页实现书架布局样式

//// FWBookShelfDecarationViewCollectionReusableView.h// FWPersonalApp//// Created by hzkmn on 16/2/18.// Copyright © 2016年 ForrstWoo. All rights reserved.//#import <UIKit/UIKit.h>extern NSInteger const kDecorationViewHeight;@interface FWBookShelfDecarationView : UICollectionReusableView@end

//// FWBookShelfDecarationViewCollectionReusableView.m// FWPersonalApp//// Created by hzkmn on 16/2/18.// Copyright © 2016年 ForrstWoo. All rights reserved.//#import "FWBookShelfDecarationView.h"NSInteger const kDecorationViewHeight = 216;@implementation FWBookShelfDecarationView- (instancetype)initWithFrame:(CGRect)frame{  if (self = [super initWithFrame:frame])  {    UIImageView *img = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, screenSize.width, kDecorationViewHeight)];    img.image = [UIImage imageNamed:@"boolshelf.png"];    [self addSubview:img];  }    return self;}@end 

//// LXReorderableCollectionViewFlowLayout.h//// Created by Stan Chang Khin Boon on 1/10/12.// Copyright (c) 2012 d--buzz. All rights reserved.//#import <UIKit/UIKit.h>@interface LXReorderableCollectionViewFlowLayout : UICollectionViewFlowLayout <UIGestureRecognizerDelegate>@property (assign, nonatomic) CGFloat scrollingSpeed;@property (assign, nonatomic) UIEdgeInsets scrollingTriggerEdgeInsets;@property (strong, nonatomic, readonly) UILongPressGestureRecognizer *longPressGestureRecognizer;@property (strong, nonatomic, readonly) UIPanGestureRecognizer *panGestureRecognizer;- (void)setUpGestureRecognizersOnCollectionView __attribute__((deprecated("Calls to setUpGestureRecognizersOnCollectionView method are not longer needed as setup are done automatically through KVO.")));@end@protocol LXReorderableCollectionViewDataSource <UICollectionViewDataSource>@optional- (void)collectionView:(UICollectionView *)collectionView itemAtIndexPath:(NSIndexPath *)fromIndexPath willMoveToIndexPath:(NSIndexPath *)toIndexPath;- (void)collectionView:(UICollectionView *)collectionView itemAtIndexPath:(NSIndexPath *)fromIndexPath didMoveToIndexPath:(NSIndexPath *)toIndexPath;- (BOOL)collectionView:(UICollectionView *)collectionView canMoveItemAtIndexPath:(NSIndexPath *)indexPath;- (BOOL)collectionView:(UICollectionView *)collectionView itemAtIndexPath:(NSIndexPath *)fromIndexPath canMoveToIndexPath:(NSIndexPath *)toIndexPath;@end@protocol LXReorderableCollectionViewDelegateFlowLayout <UICollectionViewDelegateFlowLayout>@optional- (void)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout willBeginDraggingItemAtIndexPath:(NSIndexPath *)indexPath;- (void)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout didBeginDraggingItemAtIndexPath:(NSIndexPath *)indexPath;- (void)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout willEndDraggingItemAtIndexPath:(NSIndexPath *)indexPath;- (void)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout didEndDraggingItemAtIndexPath:(NSIndexPath *)indexPath;@end

//// LXReorderableCollectionViewFlowLayout.m//// Created by Stan Chang Khin Boon on 1/10/12.// Copyright (c) 2012 d--buzz. All rights reserved.//#import "LXReorderableCollectionViewFlowLayout.h"#import <QuartzCore/QuartzCore.h>#import <objc/runtime.h>#define LX_FRAMES_PER_SECOND 60.0#ifndef CGGEOMETRY_LXSUPPORT_H_CG_INLINE CGPointLXS_CGPointAdd(CGPoint point1, CGPoint point2) {  return CGPointMake(point1.x + point2.x, point1.y + point2.y);}#endiftypedef NS_ENUM(NSInteger, LXScrollingDirection) {  LXScrollingDirectionUnknown = 0,  LXScrollingDirectionUp,  LXScrollingDirectionDown,  LXScrollingDirectionLeft,  LXScrollingDirectionRight};static NSString * const kLXScrollingDirectionKey = @"LXScrollingDirection";static NSString * const kLXCollectionViewKeyPath = @"collectionView";@interface CADisplayLink (LX_userInfo)@property (nonatomic, copy) NSDictionary *LX_userInfo;@end@implementation CADisplayLink (LX_userInfo)- (void) setLX_userInfo:(NSDictionary *) LX_userInfo {  objc_setAssociatedObject(self, "LX_userInfo", LX_userInfo, OBJC_ASSOCIATION_COPY);}- (NSDictionary *) LX_userInfo {  return objc_getAssociatedObject(self, "LX_userInfo");}@end@interface UICollectionViewCell (LXReorderableCollectionViewFlowLayout)- (UIImage *)LX_rasterizedImage;@end@implementation UICollectionViewCell (LXReorderableCollectionViewFlowLayout)- (UIImage *)LX_rasterizedImage {  UIGraphicsBeginImageContextWithOptions(self.bounds.size, self.isOpaque, 0.0f);  [self.layer renderInContext:UIGraphicsGetCurrentContext()];  UIImage *image = UIGraphicsGetImageFromCurrentImageContext();  UIGraphicsEndImageContext();  return image;}@end@interface LXReorderableCollectionViewFlowLayout ()@property (strong, nonatomic) NSIndexPath *selectedItemIndexPath;@property (strong, nonatomic) UIView *currentView;@property (assign, nonatomic) CGPoint currentViewCenter;@property (assign, nonatomic) CGPoint panTranslationInCollectionView;@property (strong, nonatomic) CADisplayLink *displayLink;@property (assign, nonatomic, readonly) id<LXReorderableCollectionViewDataSource> dataSource;@property (assign, nonatomic, readonly) id<LXReorderableCollectionViewDelegateFlowLayout> delegate;@end@implementation LXReorderableCollectionViewFlowLayout- (void)setDefaults {  _scrollingSpeed = 300.0f;  _scrollingTriggerEdgeInsets = UIEdgeInsetsMake(50.0f, 50.0f, 50.0f, 50.0f);}- (void)setupCollectionView {  _longPressGestureRecognizer = [[UILongPressGestureRecognizer alloc] initWithTarget:self                                        action:@selector(handleLongPressGesture:)];  _longPressGestureRecognizer.delegate = self;    // Links the default long press gesture recognizer to the custom long press gesture recognizer we are creating now  // by enforcing failure dependency so that they doesn't clash.  for (UIGestureRecognizer *gestureRecognizer in self.collectionView.gestureRecognizers) {    if ([gestureRecognizer isKindOfClass:[UILongPressGestureRecognizer class]]) {      [gestureRecognizer requireGestureRecognizerToFail:_longPressGestureRecognizer];    }  }    [self.collectionView addGestureRecognizer:_longPressGestureRecognizer];    _panGestureRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self                                  action:@selector(handlePanGesture:)];  _panGestureRecognizer.delegate = self;  [self.collectionView addGestureRecognizer:_panGestureRecognizer];  // Useful in multiple scenarios: one common scenario being when the Notification Center drawer is pulled down  [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(handleApplicationWillResignActive:) name: UIApplicationWillResignActiveNotification object:nil];}- (id)init {  self = [super init];  if (self) {    [self setDefaults];    [self addObserver:self forKeyPath:kLXCollectionViewKeyPath options:NSKeyValueObservingOptionNew context:nil];  }  return self;}- (id)initWithCoder:(NSCoder *)aDecoder {  self = [super initWithCoder:aDecoder];  if (self) {    [self setDefaults];    [self addObserver:self forKeyPath:kLXCollectionViewKeyPath options:NSKeyValueObservingOptionNew context:nil];  }  return self;}- (void)dealloc {  [self invalidatesScrollTimer];  [self removeObserver:self forKeyPath:kLXCollectionViewKeyPath];  [[NSNotificationCenter defaultCenter] removeObserver:self name:UIApplicationWillResignActiveNotification object:nil];}- (void)applyLayoutAttributes:(UICollectionViewLayoutAttributes *)layoutAttributes {  if ([layoutAttributes.indexPath isEqual:self.selectedItemIndexPath]) {    layoutAttributes.hidden = YES;  }}- (id<LXReorderableCollectionViewDataSource>)dataSource {  return (id<LXReorderableCollectionViewDataSource>)self.collectionView.dataSource;}- (id<LXReorderableCollectionViewDelegateFlowLayout>)delegate {  return (id<LXReorderableCollectionViewDelegateFlowLayout>)self.collectionView.delegate;}- (void)invalidateLayoutIfNecessary {  NSIndexPath *newIndexPath = [self.collectionView indexPathForItemAtPoint:self.currentView.center];  NSIndexPath *previousIndexPath = self.selectedItemIndexPath;    if ((newIndexPath == nil) || [newIndexPath isEqual:previousIndexPath]) {    return;  }    if ([self.dataSource respondsToSelector:@selector(collectionView:itemAtIndexPath:canMoveToIndexPath:)] &&    ![self.dataSource collectionView:self.collectionView itemAtIndexPath:previousIndexPath canMoveToIndexPath:newIndexPath]) {    return;  }    self.selectedItemIndexPath = newIndexPath;    if ([self.dataSource respondsToSelector:@selector(collectionView:itemAtIndexPath:willMoveToIndexPath:)]) {    [self.dataSource collectionView:self.collectionView itemAtIndexPath:previousIndexPath willMoveToIndexPath:newIndexPath];  }  __weak typeof(self) weakSelf = self;  [self.collectionView performBatchUpdates:^{    __strong typeof(self) strongSelf = weakSelf;    if (strongSelf) {      [strongSelf.collectionView deleteItemsAtIndexPaths:@[ previousIndexPath ]];      [strongSelf.collectionView insertItemsAtIndexPaths:@[ newIndexPath ]];    }  } completion:^(BOOL finished) {    __strong typeof(self) strongSelf = weakSelf;    if ([strongSelf.dataSource respondsToSelector:@selector(collectionView:itemAtIndexPath:didMoveToIndexPath:)]) {      [strongSelf.dataSource collectionView:strongSelf.collectionView itemAtIndexPath:previousIndexPath didMoveToIndexPath:newIndexPath];    }  }];}- (void)invalidatesScrollTimer {  if (!self.displayLink.paused) {    [self.displayLink invalidate];  }  self.displayLink = nil;}- (void)setupScrollTimerInDirection:(LXScrollingDirection)direction {  if (!self.displayLink.paused) {    LXScrollingDirection oldDirection = [self.displayLink.LX_userInfo[kLXScrollingDirectionKey] integerValue];    if (direction == oldDirection) {      return;    }  }    [self invalidatesScrollTimer];  self.displayLink = [CADisplayLink displayLinkWithTarget:self selector:@selector(handleScroll:)];  self.displayLink.LX_userInfo = @{ kLXScrollingDirectionKey : @(direction) };  [self.displayLink addToRunLoop:[NSRunLoop mainRunLoop] forMode:NSRunLoopCommonModes];}#pragma mark - Target/Action methods// Tight loop, allocate memory sparely, even if they are stack allocation.- (void)handleScroll:(CADisplayLink *)displayLink {  LXScrollingDirection direction = (LXScrollingDirection)[displayLink.LX_userInfo[kLXScrollingDirectionKey] integerValue];  if (direction == LXScrollingDirectionUnknown) {    return;  }    CGSize frameSize = self.collectionView.bounds.size;  CGSize contentSize = self.collectionView.contentSize;  CGPoint contentOffset = self.collectionView.contentOffset;  UIEdgeInsets contentInset = self.collectionView.contentInset;  // Important to have an integer `distance` as the `contentOffset` property automatically gets rounded  // and it would diverge from the view's center resulting in a "cell is slipping away under finger"-bug.  CGFloat distance = rint(self.scrollingSpeed / LX_FRAMES_PER_SECOND);  CGPoint translation = CGPointZero;    switch(direction) {    case LXScrollingDirectionUp: {      distance = -distance;      CGFloat minY = 0.0f - contentInset.top;            if ((contentOffset.y + distance) <= minY) {        distance = -contentOffset.y - contentInset.top;      }            translation = CGPointMake(0.0f, distance);    } break;    case LXScrollingDirectionDown: {      CGFloat maxY = MAX(contentSize.height, frameSize.height) - frameSize.height + contentInset.bottom;            if ((contentOffset.y + distance) >= maxY) {        distance = maxY - contentOffset.y;      }            translation = CGPointMake(0.0f, distance);    } break;    case LXScrollingDirectionLeft: {      distance = -distance;      CGFloat minX = 0.0f - contentInset.left;            if ((contentOffset.x + distance) <= minX) {        distance = -contentOffset.x - contentInset.left;      }            translation = CGPointMake(distance, 0.0f);    } break;    case LXScrollingDirectionRight: {      CGFloat maxX = MAX(contentSize.width, frameSize.width) - frameSize.width + contentInset.right;            if ((contentOffset.x + distance) >= maxX) {        distance = maxX - contentOffset.x;      }            translation = CGPointMake(distance, 0.0f);    } break;    default: {      // Do nothing...    } break;  }    self.currentViewCenter = LXS_CGPointAdd(self.currentViewCenter, translation);  self.currentView.center = LXS_CGPointAdd(self.currentViewCenter, self.panTranslationInCollectionView);  self.collectionView.contentOffset = LXS_CGPointAdd(contentOffset, translation);}- (void)handleLongPressGesture:(UILongPressGestureRecognizer *)gestureRecognizer {  switch(gestureRecognizer.state) {    case UIGestureRecognizerStateBegan: {      NSIndexPath *currentIndexPath = [self.collectionView indexPathForItemAtPoint:[gestureRecognizer locationInView:self.collectionView]];            if ([self.dataSource respondsToSelector:@selector(collectionView:canMoveItemAtIndexPath:)] &&        ![self.dataSource collectionView:self.collectionView canMoveItemAtIndexPath:currentIndexPath]) {        return;      }            self.selectedItemIndexPath = currentIndexPath;            if ([self.delegate respondsToSelector:@selector(collectionView:layout:willBeginDraggingItemAtIndexPath:)]) {        [self.delegate collectionView:self.collectionView layout:self willBeginDraggingItemAtIndexPath:self.selectedItemIndexPath];      }            UICollectionViewCell *collectionViewCell = [self.collectionView cellForItemAtIndexPath:self.selectedItemIndexPath];            self.currentView = [[UIView alloc] initWithFrame:collectionViewCell.frame];            collectionViewCell.highlighted = YES;      UIImageView *highlightedImageView = [[UIImageView alloc] initWithImage:[collectionViewCell LX_rasterizedImage]];      highlightedImageView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;      highlightedImageView.alpha = 1.0f;            collectionViewCell.highlighted = NO;      UIImageView *imageView = [[UIImageView alloc] initWithImage:[collectionViewCell LX_rasterizedImage]];      imageView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;      imageView.alpha = 0.0f;            [self.currentView addSubview:imageView];      [self.currentView addSubview:highlightedImageView];      [self.collectionView addSubview:self.currentView];            self.currentViewCenter = self.currentView.center;            __weak typeof(self) weakSelf = self;      [UIView       animateWithDuration:0.3       delay:0.0       options:UIViewAnimationOptionBeginFromCurrentState       animations:^{         __strong typeof(self) strongSelf = weakSelf;         if (strongSelf) {           strongSelf.currentView.transform = CGAffineTransformMakeScale(1.1f, 1.1f);           highlightedImageView.alpha = 0.0f;           imageView.alpha = 1.0f;         }       }       completion:^(BOOL finished) {         __strong typeof(self) strongSelf = weakSelf;         if (strongSelf) {           [highlightedImageView removeFromSuperview];                      if ([strongSelf.delegate respondsToSelector:@selector(collectionView:layout:didBeginDraggingItemAtIndexPath:)]) {             [strongSelf.delegate collectionView:strongSelf.collectionView layout:strongSelf didBeginDraggingItemAtIndexPath:strongSelf.selectedItemIndexPath];           }         }       }];            [self invalidateLayout];    } break;    case UIGestureRecognizerStateCancelled:    case UIGestureRecognizerStateEnded: {      NSIndexPath *currentIndexPath = self.selectedItemIndexPath;            if (currentIndexPath) {        if ([self.delegate respondsToSelector:@selector(collectionView:layout:willEndDraggingItemAtIndexPath:)]) {          [self.delegate collectionView:self.collectionView layout:self willEndDraggingItemAtIndexPath:currentIndexPath];        }                self.selectedItemIndexPath = nil;        self.currentViewCenter = CGPointZero;                UICollectionViewLayoutAttributes *layoutAttributes = [self layoutAttributesForItemAtIndexPath:currentIndexPath];                __weak typeof(self) weakSelf = self;        [UIView         animateWithDuration:0.3         delay:0.0         options:UIViewAnimationOptionBeginFromCurrentState         animations:^{           __strong typeof(self) strongSelf = weakSelf;           if (strongSelf) {             strongSelf.currentView.transform = CGAffineTransformMakeScale(1.0f, 1.0f);             strongSelf.currentView.center = layoutAttributes.center;           }         }         completion:^(BOOL finished) {           __strong typeof(self) strongSelf = weakSelf;           if (strongSelf) {             [strongSelf.currentView removeFromSuperview];             strongSelf.currentView = nil;             [strongSelf invalidateLayout];                          if ([strongSelf.delegate respondsToSelector:@selector(collectionView:layout:didEndDraggingItemAtIndexPath:)]) {               [strongSelf.delegate collectionView:strongSelf.collectionView layout:strongSelf didEndDraggingItemAtIndexPath:currentIndexPath];             }           }         }];      }    } break;          default: break;  }}- (void)handlePanGesture:(UIPanGestureRecognizer *)gestureRecognizer {  switch (gestureRecognizer.state) {    case UIGestureRecognizerStateBegan:    case UIGestureRecognizerStateChanged: {      self.panTranslationInCollectionView = [gestureRecognizer translationInView:self.collectionView];      CGPoint viewCenter = self.currentView.center = LXS_CGPointAdd(self.currentViewCenter, self.panTranslationInCollectionView);            [self invalidateLayoutIfNecessary];            switch (self.scrollDirection) {        case UICollectionViewScrollDirectionVertical: {          if (viewCenter.y < (CGRectGetMinY(self.collectionView.bounds) + self.scrollingTriggerEdgeInsets.top)) {            [self setupScrollTimerInDirection:LXScrollingDirectionUp];          } else {            if (viewCenter.y > (CGRectGetMaxY(self.collectionView.bounds) - self.scrollingTriggerEdgeInsets.bottom)) {              [self setupScrollTimerInDirection:LXScrollingDirectionDown];            } else {              [self invalidatesScrollTimer];            }          }        } break;        case UICollectionViewScrollDirectionHorizontal: {          if (viewCenter.x < (CGRectGetMinX(self.collectionView.bounds) + self.scrollingTriggerEdgeInsets.left)) {            [self setupScrollTimerInDirection:LXScrollingDirectionLeft];          } else {            if (viewCenter.x > (CGRectGetMaxX(self.collectionView.bounds) - self.scrollingTriggerEdgeInsets.right)) {              [self setupScrollTimerInDirection:LXScrollingDirectionRight];            } else {              [self invalidatesScrollTimer];            }          }        } break;      }    } break;    case UIGestureRecognizerStateCancelled:    case UIGestureRecognizerStateEnded: {      [self invalidatesScrollTimer];    } break;    default: {      // Do nothing...    } break;  }}#pragma mark - UICollectionViewLayout overridden methods- (NSArray *)layoutAttributesForElementsInRect:(CGRect)rect {  NSArray *layoutAttributesForElementsInRect = [super layoutAttributesForElementsInRect:rect];    for (UICollectionViewLayoutAttributes *layoutAttributes in layoutAttributesForElementsInRect) {    switch (layoutAttributes.representedElementCategory) {      case UICollectionElementCategoryCell: {        [self applyLayoutAttributes:layoutAttributes];      } break;      default: {        // Do nothing...      } break;    }  }    return layoutAttributesForElementsInRect;}- (UICollectionViewLayoutAttributes *)layoutAttributesForItemAtIndexPath:(NSIndexPath *)indexPath {  UICollectionViewLayoutAttributes *layoutAttributes = [super layoutAttributesForItemAtIndexPath:indexPath];    switch (layoutAttributes.representedElementCategory) {    case UICollectionElementCategoryCell: {      [self applyLayoutAttributes:layoutAttributes];    } break;    default: {      // Do nothing...    } break;  }    return layoutAttributes;}#pragma mark - UIGestureRecognizerDelegate methods- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer {  if ([self.panGestureRecognizer isEqual:gestureRecognizer]) {    return (self.selectedItemIndexPath != nil);  }  return YES;}- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer {  if ([self.longPressGestureRecognizer isEqual:gestureRecognizer]) {    return [self.panGestureRecognizer isEqual:otherGestureRecognizer];  }    if ([self.panGestureRecognizer isEqual:gestureRecognizer]) {    return [self.longPressGestureRecognizer isEqual:otherGestureRecognizer];  }    return NO;}#pragma mark - Key-Value Observing methods- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {  if ([keyPath isEqualToString:kLXCollectionViewKeyPath]) {    if (self.collectionView != nil) {      [self setupCollectionView];    } else {      [self invalidatesScrollTimer];    }  }}#pragma mark - Notifications- (void)handleApplicationWillResignActive:(NSNotification *)notification {  self.panGestureRecognizer.enabled = NO;  self.panGestureRecognizer.enabled = YES;}#pragma mark - Depreciated methods#pragma mark Starting from 0.1.0- (void)setUpGestureRecognizersOnCollectionView {  // Do nothing...}@end

//// FWBookshelfCollectionViewLayout.h// FWPersonalApp//// Created by hzkmn on 16/2/18.// Copyright © 2016年 ForrstWoo. All rights reserved.//#import "LXReorderableCollectionViewFlowLayout.h"extern NSString * const FWBookshelfCollectionViewLayoutDecorationViewKind;@interface FWBookshelfCollectionViewLayout : LXReorderableCollectionViewFlowLayout@end

//// FWBookshelfCollectionViewLayout.m// FWPersonalApp//// Created by hzkmn on 16/2/18.// Copyright © 2016年 ForrstWoo. All rights reserved.//#import "FWBookshelfCollectionViewLayout.h"#import "FWBookShelfDecarationView.h"NSString * const FWBookshelfCollectionViewLayoutDecorationViewKind = @"FWBookshelfCollectionViewLayoutDecorationViewKind";@interface FWBookshelfCollectionViewLayout ()@property (nonatomic, strong) NSDictionary *bookShelfRectanges;@property NSInteger countOfRow;@end@implementation FWBookshelfCollectionViewLayout- (void)prepareLayout{  [super prepareLayout];    [self registerClass:[FWBookShelfDecarationView class] forDecorationViewOfKind:FWBookshelfCollectionViewLayoutDecorationViewKind];    NSMutableDictionary *dictionary = [NSMutableDictionary dictionary];    NSInteger itemCount = [self.collectionView numberOfItemsInSection:0];  self.countOfRow = ceilf(itemCount / 3.0);  for (int row = 0; row < self.countOfRow; row++)  {    dictionary[[NSIndexPath indexPathForItem:row inSection:0]] = [NSValue valueWithCGRect:CGRectMake(0, kDecorationViewHeight * row, screenSize.width, kDecorationViewHeight)];  }    self.bookShelfRectanges = [NSDictionary dictionaryWithDictionary:dictionary];}#pragma mark Runtime Layout Calculations- (NSArray *)layoutAttributesForElementsInRect:(CGRect)rect{  // call super so flow layout can return default attributes for all cells, headers, and footers  // NOTE: Flow layout has already taken care of the Cell view layout attributes! :)  NSArray *array = [super layoutAttributesForElementsInRect:rect];    // create a mutable copy so we can add layout attributes for any shelfs that  // have frames that intersect the rect the CollectionView is interested in  NSMutableArray *newArray = [array mutableCopy];  //  NSLog(@"in rect:%@",NSStringFromCGRect(rect));  // Add any decoration views (shelves) who's rect intersects with the  // CGRect passed to the layout by the CollectionView  [self.bookShelfRectanges enumerateKeysAndObjectsUsingBlock:^(id key, id shelfRect, BOOL *stop) {    //    NSLog(@"[shelfRect CGRectValue]:%@",NSStringFromCGRect([shelfRect CGRectValue]));        if (CGRectIntersectsRect([shelfRect CGRectValue], rect))    {      UICollectionViewLayoutAttributes *shelfAttributes =      [self layoutAttributesForDecorationViewOfKind:FWBookshelfCollectionViewLayoutDecorationViewKind                       atIndexPath:key];      [newArray addObject:shelfAttributes];    }  }];    for (int i = 0; i < [self.collectionView numberOfItemsInSection:0]; i++)  {    NSIndexPath *indexPath = [NSIndexPath indexPathForItem:i inSection:0];        [newArray addObject:[self layoutAttributesForItemAtIndexPath:indexPath]];  }    return [newArray copy];}- (UICollectionViewLayoutAttributes *)layoutAttributesForItemAtIndexPath:(NSIndexPath *)indexPath{  //  NSLog(@"%@", NSStringFromCGSize([self screenSize]));375 667  UICollectionViewLayoutAttributes *attris = [UICollectionViewLayoutAttributes layoutAttributesForCellWithIndexPath:indexPath];    NSInteger currentRow = indexPath.item / 3;  CGRect frame = CGRectMake(20 + (indexPath.item % 3) * (kCellWidth + 17.5), 35+ currentRow * (kCellHeight + 65), kCellWidth, kCellHeight);  attris.frame = frame;  attris.zIndex = 1;    return attris;}- (UICollectionViewLayoutAttributes *)layoutAttributesForDecorationViewOfKind:(NSString *)decorationViewKind atIndexPath:(NSIndexPath *)indexPath{    id shelfRect = self.bookShelfRectanges[indexPath];    // this should never happen, but just in case...  if (!shelfRect)    return nil;    UICollectionViewLayoutAttributes *attributes =  [UICollectionViewLayoutAttributes layoutAttributesForDecorationViewOfKind:decorationViewKind                                withIndexPath:indexPath];  attributes.frame = [shelfRect CGRectValue];  //  NSLog(@"UICollectionViewLayoutAttributes :.%@", NSStringFromCGRect([shelfRect CGRectValue]));    attributes.zIndex = -1; // shelves go behind other views    return attributes;}- (CGSize)collectionViewContentSize{  CGSize contentSize = CGSizeMake(self.collectionView.bounds.size.width, self.countOfRow * kDecorationViewHeight + 20);    return contentSize;}@end

//// FWAncientPoetryCollectionViewController.m// FWPersonalApp//// Created by hzkmn on 16/2/17.// Copyright © 2016年 ForrstWoo. All rights reserved.//#import "FWAncientPoetryCollectionViewController.h"#import "FWBookShelfDecarationView.h"#import "FWBookshelfCollectionViewLayout.h"#import "FWBookCategoryViewController.h"@interface FWAncientPoetryCollectionViewController () <LXReorderableCollectionViewDataSource, LXReorderableCollectionViewDelegateFlowLayout>@property (nonatomic, strong) NSMutableArray *books;@end@implementation FWAncientPoetryCollectionViewControllerstatic NSString * const cellReuseIdentifier = @"Cell";- (void)viewDidLoad {  [super viewDidLoad];  self.title = @"古籍";  self.collectionView.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"bookShelfBackground.png"]];  [self.collectionView registerClass:[UICollectionViewCell class] forCellWithReuseIdentifier:cellReuseIdentifier];  self.books = [[NSMutableArray alloc] initWithArray:[self bookNameOfAllBooks]];}- (NSArray *)bookNameOfAllBooks{ return [[FWDataManager getDataForPoetry] allKeys];}#pragma mark <UICollectionViewDataSource>- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView{  return 1;}- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section{  return [self.books count];}- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath{  UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:cellReuseIdentifier forIndexPath:indexPath];  UIImage *image = [UIImage imageNamed:self.books[indexPath.item]];  cell.backgroundColor = [UIColor colorWithPatternImage:image];  return cell;}- (void)collectionView:(UICollectionView *)collectionView itemAtIndexPath:(NSIndexPath *)fromIndexPath willMoveToIndexPath:(NSIndexPath *)toIndexPath{  NSString *theBookName = self.books[fromIndexPath.item];  [self.books removeObjectAtIndex:fromIndexPath.item];  [self.books insertObject:theBookName atIndex:toIndexPath.item];}#pragma mark - UICollectionViewDelegateFlowLayout- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath{  return CGSizeMake(kCellWidth, kCellHeight);}- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath{  FWBookCategoryViewController *vc = [[FWBookCategoryViewController alloc] initWithUrlString:[[FWDataManager getDataForPoetry] objectForKey:self.books[indexPath.item]]];  [self.navigationController pushViewController:vc animated:YES];}- (void)didReceiveMemoryWarning {  [super didReceiveMemoryWarning];  [self.books removeAllObjects];  self.books = nil;}@end