iOS实现UICollectionViewDataSource与Controller的分离

之前每次用到UICollectionView的时候都会都需要在Controller里面去实现DataSource & Delegate方法

单独Delegate方法还好不是很多, 但是再加上DataSource就很臃肿了, 为了避免代码臃肿也减少ViewController的代码量

我们可以将DataSource方法分离出去, 大致方法如下:

-> 创建需要的Model & 自定义Cell文件

-> 创建DataSource类, 导入 Cell头文件并实现UICollectionViewDatasource

-> 在Controller中导入Model & DataSource类

-> 创建DataSource类实例, 将数据传入DataSource中

-> 创建UICollectionView, 将CollectionView的datasource指给上面创建的Datasource实例即可

下面举例示范:

为了简单 我就只下一个自定义的Cell model就不写了

ShowPhotoCollectionViewCell.h

 #import <UIKit/UIKit.h>

 @interface ShowPhotoCollectionViewCell : UICollectionViewCell

 @property (nonatomic, strong) UILabel     *lable;
 @property (nonatomic, strong) UIImageView *imageView;

 /**
  配置Cell方法

  @param imageLink 图片地址
  @param title 标题
  */
 - (void)configCellWithImageLink:(NSString *)imageLink withTitle:(NSString *)title;
 @end

ShowPhotoCollectionViewCell.m

 #import "ShowPhotoCollectionViewCell.h"
 #import "UIImageView+WebCache.h"
 #import "UIImage+Image.h"

 @implementation ShowPhotoCollectionViewCell

 - (id)initWithFrame:(CGRect)frame {

     self = [super initWithFrame:frame];
     if (self) {

         self.lable = ({

             UILabel *lable        = [[UILabel alloc] initWithFrame:\
                                      CGRectMake((SCREEN_WIDTH - ) / , , , )];

             lable.textAlignment   = NSTextAlignmentCenter;
             lable.font            = [UIFont systemFontOfSize:];
             lable.backgroundColor = [UIColor blackColor];
             lable.textColor       = [UIColor whiteColor];

             lable;
         });

         self.imageView = ({

             UIImageView *imgView = [[UIImageView alloc] initWithFrame:CGRectMake(, , SCREEN_WIDTH - , SCREEN_HEIGHT -  - )];

             imgView;
         });

         [self addSubview:self.lable];
         [self addSubview:self.imageView];
     }

     return self;
 }

 - (void)configCellWithImageLink:(NSString *)imageLink withTitle:(NSString *)title {

     self.lable.text = title;
     [self.imageView sd_setImageWithURL:[NSURL URLWithString:imageLink]
                       placeholderImage:[UIImage imageWithColor:[UIColor whiteColor]]];
 }

 @end

ShowPhotoDataSource.h

 #import <Foundation/Foundation.h>
 #import <UIKit/UIKit.h>

 @interface ShowPhotoDataSource : NSObject <UICollectionViewDataSource>

 @property (nonatomic, strong) NSArray  *imgLinkArray;
 @property (nonatomic, strong) NSString *identifier;

 /**
  导入外部数据

  @param linkArray Image地址数组
  @param identifier cell标识
  @return 返回实例
  */
 - (id)initWithImageLinkArray:(NSArray *)linkArray withIdentifier:(NSString *)identifier;

 /**
  根据索引返回图片地址

  @param indexPath 索引
  @return 返回图片地址
  */
 - (id)imgLinkAtIndexPath:(NSIndexPath *)indexPath;

 @end

ShowPhotoDataSource.m

 #import "ShowPhotoDataSource.h"
 #import "ShowPhotoCollectionViewCell.h"

 @implementation ShowPhotoDataSource

 - (id)initWithImageLinkArray:(NSArray *)linkArray withIdentifier:(NSString *)identifier{

     self = [super init];
     if (self) {

         self.imgLinkArray = linkArray;
         self.identifier   = identifier;
     }

     return self;
 }

 - (id)imgLinkAtIndexPath:(NSIndexPath *)indexPath {

     return self.imgLinkArray[indexPath.row];
 }

 #pragma mark - CollectionView dataSource Methods
 - (NSInteger)collectionView:(UICollectionView *)collectionView
      numberOfItemsInSection:(NSInteger)section {

     return self.imgLinkArray.count;
 }

 - (__kindof UICollectionViewCell *)collectionView:(UICollectionView *)collectionView
                            cellForItemAtIndexPath:(NSIndexPath *)indexPath {

     ShowPhotoCollectionViewCell *cell = \
     [collectionView dequeueReusableCellWithReuseIdentifier:self.identifier
                                               forIndexPath:indexPath];
     [cell configCellWithImageLink:[self imgLinkAtIndexPath:indexPath]
                         withTitle:\
      [NSString stringWithFormat:@"%d/%d", indexPath.row +  , self.imgLinkArray.count]];

     return cell;
 }

 @end

下面是在Controller中的使用方法

 //创建CollectionView
 - (void)createCollectionView {

     self.dataSource = ({

         PhotoDataSource *dataSource = [[PhotoDataSource alloc] \
                                        initWithImageLinkArray:self.imglinkArray
                                                withIdentifier:PHOTOCELLIDENTIFIER];

         dataSource;
     });

     self.myCollectionView = ({

         UICollectionViewFlowLayout *layout = [[UICollectionViewFlowLayout alloc] init];
         [layout setScrollDirection:UICollectionViewScrollDirectionHorizontal];

         UICollectionView *collection       = [[UICollectionView alloc] initWithFrame:\
                         CGRectMake(, , SCREEN_WIDTH, SCREEN_HEIGHT) collectionViewLayout:layout];

         [collection registerClass:[PhotoCollectionViewCell class]
                                                     forCellWithReuseIdentifier:PHOTOCELLIDENTIFIER];

         collection.showsHorizontalScrollIndicator = NO;
         collection.dataSource                     = self.dataSource;
         collection.delegate                       = self;

         collection;
     });

     [self.view addSubview:self.myCollectionView];
 }