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[操作系统]通过自定义相册来介绍photo library的使用


  因为我在模仿美图秀秀的功能,在使用相册时候,UIImagePickerController本来就是一个UINavigationController的子类,所以没有办法使用push,所以做了一个自定义的非UINavigationController子类的相册。使用的api是ios8以上提供的photokit。

  一、获取相册的所有相册集

  例如:个人收藏,最近添加,相机胶卷等。

  1.使用+ (PHFetchResult<PHAssetCollection *> *)fetchAssetCollectionsWithType:(PHAssetCollectionType)type subtype:(PHAssetCollectionSubtype)subtype options:(nullable PHFetchOptions *)options方法来获取相册集集合

PHFetchResult返回了结果

  2.使用+ (PHFetchResult<PHAsset *> *)fetchAssetsInAssetCollection:(PHAssetCollection *)assetCollection options:(nullable PHFetchOptions *)options方法来获取相册集内的所有照片资源

  

- (PHFetchResult *)fetchAssetsInAssetCollection:(PHAssetCollection *)assetCollection ascending:(BOOL)ascending{  PHFetchOptions *options = [[PHFetchOptions alloc] init];  options.sortDescriptors = @[[NSSortDescriptor sortDescriptorWithKey:@"creationDate" ascending:ascending]];  PHFetchResult *result = [PHAsset fetchAssetsInAssetCollection:assetCollection options:options];    return result;}- (NSArray <PHAsset *> *)getAssetsInAssetCollection:(PHAssetCollection *)assetCollection ascending:(BOOL)ascending{  NSMutableArray <PHAsset *> *mArr = [NSMutableArray array];  PHFetchResult *result = [self fetchAssetsInAssetCollection:assetCollection ascending:ascending];  [result enumerateObjectsUsingBlock:^(PHAsset * _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {    if (obj.mediaType == PHAssetMediaTypeImage) {      [mArr addObject:obj];    }  }];    return mArr;}- (NSArray<PHAsset *> *)getAllAssetInPhotoAblumWithAscending:(BOOL)ascending{  NSMutableArray<PHAsset *> *assets = [NSMutableArray array];    PHFetchOptions *option = [[PHFetchOptions alloc] init];    option.sortDescriptors = @[[NSSortDescriptor sortDescriptorWithKey:@"creationDate" ascending:ascending]];    PHFetchResult *result = [PHAsset fetchAssetsWithMediaType:PHAssetMediaTypeImage options:option];    [result enumerateObjectsUsingBlock:^(PHAsset * _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {    [assets addObject:obj];  }];    return assets;}- (NSArray <FWPhotoAlbums *> *)getPhotoAlbums{  NSMutableArray<FWPhotoAlbums *> *mArr = [NSMutableArray array];  PHFetchResult *smartAlbum = [PHAssetCollection fetchAssetCollectionsWithType:PHAssetCollectionTypeSmartAlbum subtype:PHAssetCollectionSubtypeAlbumRegular options:nil];  [smartAlbum enumerateObjectsUsingBlock:^(PHAssetCollection * _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {    if (obj.assetCollectionSubtype != 202 && obj.assetCollectionSubtype < 212) {      NSArray <PHAsset *> *assets = [self getAssetsInAssetCollection:obj ascending:NO];      if ([assets count]) {        FWPhotoAlbums *pa = [[FWPhotoAlbums alloc] init];        pa.albumName = [self TitleOfAlbumForChinse:obj.localizedTitle];        pa.albumImageCount = [assets count];        pa.firstImageAsset = assets.firstObject;        pa.assetCollection = obj;        [mArr addObject:pa];      }    }  }];    PHFetchResult *userAlbums = [PHAssetCollection fetchAssetCollectionsWithType:PHAssetCollectionTypeAlbum subtype:PHAssetCollectionSubtypeSmartAlbumUserLibrary options:nil];  [userAlbums enumerateObjectsUsingBlock:^(PHAssetCollection * _Nonnull collection, NSUInteger idx, BOOL * _Nonnull stop) {    NSArray<PHAsset *> *assets = [self getAssetsInAssetCollection:collection ascending:YES];    if (assets.count > 0) {      FWPhotoAlbums *pa = [[FWPhotoAlbums alloc] init];      pa.albumName = collection.localizedTitle;      pa.albumImageCount = [assets count];      pa.firstImageAsset = assets.firstObject;      pa.assetCollection = collection;      [mArr addObject:pa];    }  }];    return mArr;}

由于系统返回的相册集名称为英文,我们需要转换为中文

- (NSString *)TitleOfAlbumForChinse:(NSString *)title{  if ([title isEqualToString:@"Slo-mo"]) {    return @"慢动作";  } else if ([title isEqualToString:@"Recently Added"]) {    return @"最近添加";  } else if ([title isEqualToString:@"Favorites"]) {    return @"个人收藏";  } else if ([title isEqualToString:@"Recently Deleted"]) {    return @"最近删除";  } else if ([title isEqualToString:@"Videos"]) {    return @"视频";  } else if ([title isEqualToString:@"All Photos"]) {    return @"所有照片";  } else if ([title isEqualToString:@"Selfies"]) {    return @"自拍";  } else if ([title isEqualToString:@"Screenshots"]) {    return @"屏幕快照";  } else if ([title isEqualToString:@"Camera Roll"]) {    return @"相机胶卷";  }  return nil;}

 

二、获取照片

- (void)requestImageForAsset:(PHAsset *)asset size:(CGSize)size resizeMode:(PHImageRequestOptionsResizeMode)resizeMode completion:(void (^)(UIImage *, NSDictionary *))completion{  static PHImageRequestID requestID = -1;  CGFloat scale = [UIScreen mainScreen].scale;  CGFloat width = MIN(WIDTH, 800);  if (requestID >= 1 && size.width/width==scale) {    [[PHCachingImageManager defaultManager] cancelImageRequest:requestID];  }    PHImageRequestOptions *option = [[PHImageRequestOptions alloc] init];  option.resizeMode = resizeMode;  option.networkAccessAllowed = YES;    requestID = [[PHCachingImageManager defaultManager] requestImageForAsset:asset targetSize:size contentMode:PHImageContentModeAspectFill options:option resultHandler:^(UIImage * _Nullable image, NSDictionary * _Nullable info) {    BOOL downloadFinined = ![[info objectForKey:PHImageCancelledKey] boolValue] && ![info objectForKey:PHImageErrorKey];    if (downloadFinined && completion) {      completion(image, info);    }  }];}

 

 

 三、拍照

 [_mCamera capturePhotoAsJPEGProcessedUpToFilter:_mFilter withCompletionHandler:^(NSData *processedJPEG, NSError *error){    [[PHPhotoLibrary sharedPhotoLibrary] performChanges:^{    [[PHAssetCreationRequest creationRequestForAsset] addResourceWithType:PHAssetResourceTypePhoto data:processedJPEG options:nil];    } completionHandler:^(BOOL success, NSError * _Nullable error) {          }];  }];

 

 

效果

       

 

代码

1.模型类,存储相册集名称,相片数,第一张照片以及该相册集包含的所有照片集合

#import <Foundation/Foundation.h>#import <photos/photos.h>@interface FWPhotoAlbums : NSObject@property (nonatomic, copy) NSString *albumName; //相册名字@property (nonatomic, assign) NSUInteger albumImageCount; //该相册内相片数量@property (nonatomic, strong) PHAsset *firstImageAsset; //相册第一张图片缩略图@property (nonatomic, strong) PHAssetCollection *assetCollection; //相册集,通过该属性获取该相册集下所有照片@end

FWPhotoAlbums.h
#import "FWPhotoAlbums.h"@implementation FWPhotoAlbums@end

FWPhotoAlbums.m

 

2.照片管理类,负责获取资源集合,请求照片

#import <Foundation/Foundation.h>#import "FWPhotoAlbums.h"@interface FWPhotoManager : NSObject+ (instancetype)sharedManager;- (NSArray <FWPhotoAlbums *> *)getPhotoAlbums;- (NSArray<PHAsset *> *)getAllAssetInPhotoAblumWithAscending:(BOOL)ascending;- (NSArray<PHAsset *> *)getAssetsInAssetCollection:(PHAssetCollection *)assetCollection ascending:(BOOL)ascending;- (void)requestImageForAsset:(PHAsset *)asset size:(CGSize)size resizeMode:(PHImageRequestOptionsResizeMode)resizeMode completion:(void (^)(UIImage *image, NSDictionary *info))completion;- (void)requestImageForAsset:(PHAsset *)asset scale:(CGFloat)scale resizeMode:(PHImageRequestOptionsResizeMode)resizeMode completion:(void (^)(UIImage *image))completion;- (void)getPhotosBytesWithArray:(NSArray *)photos completion:(void (^)(NSString *photosBytes))completion;- (BOOL)judgeAssetisInLocalAblum:(PHAsset *)asset ;@end

FWPhotoManager.h
#import "FWPhotoManager.h"@implementation FWPhotoManager+ (instancetype)sharedManager{  static FWPhotoManager *manager = nil;  static dispatch_once_t onceToken;  dispatch_once(&onceToken, ^{    manager = [[super allocWithZone:NULL] init];  });    return manager;}+ (instancetype)allocWithZone:(struct _NSZone *)zone{  return [self sharedManager];}- (PHFetchResult *)fetchAssetsInAssetCollection:(PHAssetCollection *)assetCollection ascending:(BOOL)ascending{  PHFetchOptions *options = [[PHFetchOptions alloc] init];  options.sortDescriptors = @[[NSSortDescriptor sortDescriptorWithKey:@"creationDate" ascending:ascending]];  PHFetchResult *result = [PHAsset fetchAssetsInAssetCollection:assetCollection options:options];    return result;}- (NSArray <PHAsset *> *)getAssetsInAssetCollection:(PHAssetCollection *)assetCollection ascending:(BOOL)ascending{  NSMutableArray <PHAsset *> *mArr = [NSMutableArray array];  PHFetchResult *result = [self fetchAssetsInAssetCollection:assetCollection ascending:ascending];  [result enumerateObjectsUsingBlock:^(PHAsset * _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {    if (obj.mediaType == PHAssetMediaTypeImage) {      [mArr addObject:obj];    }  }];    return mArr;}- (NSArray<PHAsset *> *)getAllAssetInPhotoAblumWithAscending:(BOOL)ascending{  NSMutableArray<PHAsset *> *assets = [NSMutableArray array];    PHFetchOptions *option = [[PHFetchOptions alloc] init];    option.sortDescriptors = @[[NSSortDescriptor sortDescriptorWithKey:@"creationDate" ascending:ascending]];    PHFetchResult *result = [PHAsset fetchAssetsWithMediaType:PHAssetMediaTypeImage options:option];    [result enumerateObjectsUsingBlock:^(PHAsset * _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {    [assets addObject:obj];  }];    return assets;}- (NSArray <FWPhotoAlbums *> *)getPhotoAlbums{  NSMutableArray<FWPhotoAlbums *> *mArr = [NSMutableArray array];  PHFetchResult *smartAlbum = [PHAssetCollection fetchAssetCollectionsWithType:PHAssetCollectionTypeSmartAlbum subtype:PHAssetCollectionSubtypeAlbumRegular options:nil];  [smartAlbum enumerateObjectsUsingBlock:^(PHAssetCollection * _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {    if (obj.assetCollectionSubtype != 202 && obj.assetCollectionSubtype < 212) {      NSArray <PHAsset *> *assets = [self getAssetsInAssetCollection:obj ascending:NO];      if ([assets count]) {        FWPhotoAlbums *pa = [[FWPhotoAlbums alloc] init];        pa.albumName = [self TitleOfAlbumForChinse:obj.localizedTitle];        pa.albumImageCount = [assets count];        pa.firstImageAsset = assets.firstObject;        pa.assetCollection = obj;        [mArr addObject:pa];      }    }  }];    PHFetchResult *userAlbums = [PHAssetCollection fetchAssetCollectionsWithType:PHAssetCollectionTypeAlbum subtype:PHAssetCollectionSubtypeSmartAlbumUserLibrary options:nil];  [userAlbums enumerateObjectsUsingBlock:^(PHAssetCollection * _Nonnull collection, NSUInteger idx, BOOL * _Nonnull stop) {    NSArray<PHAsset *> *assets = [self getAssetsInAssetCollection:collection ascending:YES];    if (assets.count > 0) {      FWPhotoAlbums *pa = [[FWPhotoAlbums alloc] init];      pa.albumName = collection.localizedTitle;      pa.albumImageCount = [assets count];      pa.firstImageAsset = assets.firstObject;      pa.assetCollection = collection;      [mArr addObject:pa];    }  }];    return mArr;}- (NSString *)TitleOfAlbumForChinse:(NSString *)title{  if ([title isEqualToString:@"Slo-mo"]) {    return @"慢动作";  } else if ([title isEqualToString:@"Recently Added"]) {    return @"最近添加";  } else if ([title isEqualToString:@"Favorites"]) {    return @"个人收藏";  } else if ([title isEqualToString:@"Recently Deleted"]) {    return @"最近删除";  } else if ([title isEqualToString:@"Videos"]) {    return @"视频";  } else if ([title isEqualToString:@"All Photos"]) {    return @"所有照片";  } else if ([title isEqualToString:@"Selfies"]) {    return @"自拍";  } else if ([title isEqualToString:@"Screenshots"]) {    return @"屏幕快照";  } else if ([title isEqualToString:@"Camera Roll"]) {    return @"相机胶卷";  }  return nil;}- (void)requestImageForAsset:(PHAsset *)asset size:(CGSize)size resizeMode:(PHImageRequestOptionsResizeMode)resizeMode completion:(void (^)(UIImage *, NSDictionary *))completion{  static PHImageRequestID requestID = -1;  CGFloat scale = [UIScreen mainScreen].scale;  CGFloat width = MIN(WIDTH, 800);  if (requestID >= 1 && size.width/width==scale) {    [[PHCachingImageManager defaultManager] cancelImageRequest:requestID];  }    PHImageRequestOptions *option = [[PHImageRequestOptions alloc] init];  option.resizeMode = resizeMode;  option.networkAccessAllowed = YES;    requestID = [[PHCachingImageManager defaultManager] requestImageForAsset:asset targetSize:size contentMode:PHImageContentModeAspectFill options:option resultHandler:^(UIImage * _Nullable image, NSDictionary * _Nullable info) {    BOOL downloadFinined = ![[info objectForKey:PHImageCancelledKey] boolValue] && ![info objectForKey:PHImageErrorKey];    if (downloadFinined && completion) {      completion(image, info);    }  }];}- (void)requestImageForAsset:(PHAsset *)asset scale:(CGFloat)scale resizeMode:(PHImageRequestOptionsResizeMode)resizeMode completion:(void (^)(UIImage *image))completion{  PHImageRequestOptions *option = [[PHImageRequestOptions alloc] init];  option.resizeMode = resizeMode;//控制照片尺寸  option.networkAccessAllowed = YES;    [[PHCachingImageManager defaultManager] requestImageDataForAsset:asset options:option resultHandler:^(NSData * _Nullable imageData, NSString * _Nullable dataUTI, UIImageOrientation orientation, NSDictionary * _Nullable info) {    BOOL downloadFinined = ![[info objectForKey:PHImageCancelledKey] boolValue] && ![info objectForKey:PHImageErrorKey] && ![[info objectForKey:PHImageResultIsDegradedKey] boolValue];    if (downloadFinined && completion) {      CGFloat sca = imageData.length/(CGFloat)UIImageJPEGRepresentation([UIImage imageWithData:imageData], 1).length;      NSData *data = UIImageJPEGRepresentation([UIImage imageWithData:imageData], scale==1?sca:sca/2);      completion([UIImage imageWithData:data]);    }  }];}- (BOOL)judgeAssetisInLocalAblum:(PHAsset *)asset{  PHImageRequestOptions *option = [[PHImageRequestOptions alloc] init];  option.networkAccessAllowed = NO;  option.synchronous = YES;    __block BOOL isInLocalAblum = YES;    [[PHCachingImageManager defaultManager] requestImageDataForAsset:asset options:option resultHandler:^(NSData * _Nullable imageData, NSString * _Nullable dataUTI, UIImageOrientation orientation, NSDictionary * _Nullable info) {    isInLocalAblum = imageData ? YES : NO;  }];  return isInLocalAblum;}@end

FWPhotoManager.m

 

3.显示相册FWPhotoAlbumTableViewController

#import <UIKit/UIKit.h>#import <Photos/Photos.h>@interface FWPhotoAlbumTableViewController : UITableViewController//最大选择数@property (nonatomic, assign) NSInteger maxSelectCount;//是否选择了原图@property (nonatomic, assign) BOOL isCanSelectMorePhotos;//当前已经选择的图片//@property (nonatomic, strong) NSMutableArray<ZLSelectPhotoModel *> *arraySelectPhotos;//选则完成后回调//@property (nonatomic, copy) void (^DoneBlock)(NSArray<ZLSelectPhotoModel *> *selPhotoModels, BOOL isSelectOriginalPhoto);//取消选择后回调@property (nonatomic, copy) void (^CancelBlock)();@end

FWPhotoAlbumTableViewController.h
#import "FWPhotoAlbumTableViewController.h"#import "FWPhotoManager.h"#import "UIButton+TextAndImageHorizontalDisplay.h"#import "FWPhotoCollectionViewController.h"#import "FWPhotosLayout.h"@interface FWPhotoAlbumTableViewController (){  NSMutableArray<FWPhotoAlbums *> *mArr;}@end@implementation FWPhotoAlbumTableViewController- (void)viewDidLoad {  [super viewDidLoad];  self.view.backgroundColor = [UIColor whiteColor];  self.title = @"相册";    mArr= [[[FWPhotoManager sharedManager] getPhotoAlbums] mutableCopy];    [self initNavgationBar];    self.tableView.separatorStyle = UITableViewCellSeparatorStyleNone;}- (void)initNavgationBar{  UIButton *rightBar = [UIButton buttonWithType:UIButtonTypeSystem];  rightBar.frame = CGRectMake(0, 0, 68, 32);  [rightBar setImage:[UIImage imageNamed:@"Camera"] withTitle:@"相机" forState:UIControlStateNormal];  [rightBar addTarget:self action:@selector(cameraClicked) forControlEvents:UIControlEventTouchUpInside];  self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc] initWithCustomView:rightBar];}- (void)cameraClicked{  }#pragma mark - Table view data source- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {  return 1;}- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {  return [mArr count];}- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath{  return 100;}- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {  static NSString *cellID = @"cellID";  UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellID];  if (!cell)  {    cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:cellID];  }  cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;  FWPhotoAlbums *album = mArr[indexPath.row];  cell.textLabel.text =album.albumName;  cell.detailTextLabel.text = [NSString stringWithFormat:@"%d张",album.albumImageCount];  cell.detailTextLabel.textColor = [UIColor grayColor];  __block UIImage *img = nil;  [[FWPhotoManager sharedManager] requestImageForAsset:album.firstImageAsset size:CGSizeMake(60 * 3, 60 * 3) resizeMode:PHImageRequestOptionsResizeModeExact completion:^(UIImage *image, NSDictionary *info) {    img = image;  }];  cell.imageView.image = img;  cell.imageView.contentMode = UIViewContentModeScaleAspectFill;  cell.imageView.clipsToBounds = YES;  return cell;}- (BOOL)prefersStatusBarHidden{  return YES;}- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath{  FWPhotoAlbums *model = [mArr objectAtIndex:indexPath.row];  FWPhotosLayout *layout = [[FWPhotosLayout alloc] init];  layout.minimumInteritemSpacing = 1.5;  layout.minimumLineSpacing = 5.0;  FWPhotoCollectionViewController *vc = [[FWPhotoCollectionViewController alloc] initWithCollectionViewLayout:layout model:model];  [self.navigationController pushViewController:vc animated:YES];}- (void)didReceiveMemoryWarning {  [super didReceiveMemoryWarning];  // Dispose of any resources that can be recreated.}@end

FWPhotoAlbumTableViewController.m

 

4.显示相册集内所有照片FWPhotoCollectionViewController

#import <UIKit/UIKit.h>#import <Photos/Photos.h>#import "FWPhotoAlbums.h"@interface FWPhotoCollectionViewController : UICollectionViewController@property (nonatomic, strong) FWPhotoAlbums *model;- (instancetype)initWithCollectionViewLayout:(UICollectionViewLayout *)layout model:(FWPhotoAlbums *)model;@end

FWPhotoCollectionViewController.h

 

//// FWPhotoCollectionViewController.m// FWLifeApp//// Created by Forrest Woo on 16/9/23.// Copyright © 2016年 ForrstWoo. All rights reserved.//#import "FWPhotoCollectionViewController.h"#import "FWPhotoCell.h"#import "FWPhotoManager.h"#import "FWPhotosLayout.h"#import "FWDisplayBigImageViewController.h"@interface FWPhotoCollectionViewController () <UICollectionViewDelegateFlowLayout, UICollectionViewDataSource>{  NSArray<PHAsset *> *_dataSouce;}@property (nonatomic, strong) PHAssetCollection *assetCollection;@end@implementation FWPhotoCollectionViewControllerstatic NSString * const reuseIdentifier = @"Cell";- (instancetype)initWithCollectionViewLayout:(UICollectionViewLayout *)layout model:(FWPhotoAlbums *)model{  if (self = [super initWithCollectionViewLayout:layout]) {    self.model = model;  }    return self;}- (void)viewDidLoad {  [super viewDidLoad];    // Uncomment the following line to preserve selection between presentations  // self.clearsSelectionOnViewWillAppear = NO;//  self.navigationController.navigationBarHidden = YES;  // Register cell classes  CGRect frame = self.collectionView.frame;  frame.origin.y+=44;  self.collectionView.frame = frame;  self.view.backgroundColor = [UIColor whiteColor];  [self initSource];}//- (void)setModel:(FWPhotoAlbums *)model//{//  self.model = model;//  //  [self initSource];//}- (BOOL)prefersStatusBarHidden{  return YES;}- (void)initSource{  [self.collectionView registerClass:[FWPhotoCell class] forCellWithReuseIdentifier:reuseIdentifier];  self.title = self.model.albumName;  self.automaticallyAdjustsScrollViewInsets = NO;  // Do any additional setup after loading the view.  self.assetCollection = self.model.assetCollection;  _dataSouce = [[FWPhotoManager sharedManager] getAssetsInAssetCollection:self.assetCollection ascending:YES];}- (void)didReceiveMemoryWarning {  [super didReceiveMemoryWarning];  // Dispose of any resources that can be recreated.}#pragma mark <UICollectionViewDataSource>- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView {  return 1;}- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section {  return [_dataSouce count];}- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath{  FWPhotosLayout *lay = (FWPhotosLayout *)collectionViewLayout;  return CGSizeMake([lay cellWidth],[lay cellWidth]);}- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {  FWPhotoCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:reuseIdentifier forIndexPath:indexPath];  PHAsset *asset = _dataSouce[indexPath.row];  __block UIImage *bImage = nil;  CGSize size = cell.frame.size;  size.width *= 3;  size.height *= 3;  [[FWPhotoManager sharedManager] requestImageForAsset:asset size:size resizeMode:PHImageRequestOptionsResizeModeFast completion:^(UIImage *image, NSDictionary *info) {    bImage = image;  }];    [cell setImage:bImage];    return cell;}- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath{  PHAsset *asset = _dataSouce[indexPath.row];  [[FWPhotoManager sharedManager] requestImageForAsset:asset size:PHImageManagerMaximumSize resizeMode:PHImageRequestOptionsResizeModeFast completion:^(UIImage *image, NSDictionary *info) {    FWDisplayBigImageViewController *vc = [[FWDisplayBigImageViewController alloc] initWithImage:image];    [self.navigationController pushViewController:vc animated:YES];  }];  }#pragma mark <UICollectionViewDelegate>@end

FWPhotoCollectionViewController.m

 

5.布局类

#import <UIKit/UIKit.h>@interface FWPhotosLayout : UICollectionViewFlowLayout@property (nonatomic, assign,readonly)CGFloat cellWidth;@end

FWPhotosLayout.h
#import "FWPhotosLayout.h"@interface FWPhotosLayout ()@property NSInteger countOfRow;@end@implementation FWPhotosLayout- (void)prepareLayout{  [super prepareLayout];    self.countOfRow = ceilf([self.collectionView numberOfItemsInSection:0] / 4.0);}- (UICollectionViewLayoutAttributes*)layoutAttributesForItemAtIndexPath:(NSIndexPath *)indexPath{  UICollectionViewLayoutAttributes *attris = [UICollectionViewLayoutAttributes layoutAttributesForCellWithIndexPath:indexPath];  NSInteger currentRow = indexPath.item / 4;    CGRect frame = CGRectMake( (indexPath.item % 4) * ([self cellWidth] + 5),currentRow * ([self cellWidth] + 65), [self cellWidth], [self cellWidth]);  attris.frame = frame;  attris.zIndex = 1;    return attris;}- (CGFloat)cellWidth{  return (WIDTH - 3 * 5) / 4;}- (CGSize)collectionViewContentSize{  return CGSizeMake(WIDTH, self.countOfRow * ([self cellWidth] + 5) + 44);}@end

FWPhotosLayout.m

 

 

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