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 CGPoint
LXS_CGPointAdd(CGPoint point1, CGPoint point2) {
  return CGPointMake(point1.x + point2.x, point1.y + point2.y);
}
#endif

typedef 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 FWAncientPoetryCollectionViewController

static 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