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

1 #import <UIKit/UIKit.h>
2
3 @interface ShowPhotoCollectionViewCell : UICollectionViewCell
4
5 @property (nonatomic, strong) UILabel     *lable;
6 @property (nonatomic, strong) UIImageView *imageView;
7
8 /**
9  配置Cell方法
10
11  @param imageLink 图片地址
12  @param title 标题
13  */
14 - (void)configCellWithImageLink:(NSString *)imageLink withTitle:(NSString *)title;
15 @end

ShowPhotoCollectionViewCell.m

1 #import "ShowPhotoCollectionViewCell.h"
2 #import "UIImageView+WebCache.h"
3 #import "UIImage+Image.h"
4
5 @implementation ShowPhotoCollectionViewCell
6
7 - (id)initWithFrame:(CGRect)frame {
8
9     self = [super initWithFrame:frame];
10     if (self) {
11
12         self.lable = ({
13
14             UILabel *lable        = [[UILabel alloc] initWithFrame:\
15                                      CGRectMake((SCREEN_WIDTH - 40) / 2, 40, 40, 25)];
16
17             lable.textAlignment   = NSTextAlignmentCenter;
18             lable.font            = [UIFont systemFontOfSize:12];
19             lable.backgroundColor = [UIColor blackColor];
20             lable.textColor       = [UIColor whiteColor];
21
22             lable;
23         });
24
25         self.imageView = ({
26
27             UIImageView *imgView = [[UIImageView alloc] initWithFrame:CGRectMake(40, 80, SCREEN_WIDTH - 80, SCREEN_HEIGHT - 80 - 80)];
28
29             imgView;
30         });
31
32         [self addSubview:self.lable];
33         [self addSubview:self.imageView];
34     }
35
36     return self;
37 }
38
39 - (void)configCellWithImageLink:(NSString *)imageLink withTitle:(NSString *)title {
40
41     self.lable.text = title;
42     [self.imageView sd_setImageWithURL:[NSURL URLWithString:imageLink]
43                       placeholderImage:[UIImage imageWithColor:[UIColor whiteColor]]];
44 }
45
46 @end

ShowPhotoDataSource.h

1 #import <Foundation/Foundation.h>
2 #import <UIKit/UIKit.h>
3
4 @interface ShowPhotoDataSource : NSObject <UICollectionViewDataSource>
5
6 @property (nonatomic, strong) NSArray  *imgLinkArray;
7 @property (nonatomic, strong) NSString *identifier;
8
9 /**
10  导入外部数据
11
12  @param linkArray Image地址数组
13  @param identifier cell标识
14  @return 返回实例
15  */
16 - (id)initWithImageLinkArray:(NSArray *)linkArray withIdentifier:(NSString *)identifier;
17
18 /**
19  根据索引返回图片地址
20
21  @param indexPath 索引
22  @return 返回图片地址
23  */
24 - (id)imgLinkAtIndexPath:(NSIndexPath *)indexPath;
25
26 @end

ShowPhotoDataSource.m

1 #import "ShowPhotoDataSource.h"
2 #import "ShowPhotoCollectionViewCell.h"
3
4 @implementation ShowPhotoDataSource
5
6 - (id)initWithImageLinkArray:(NSArray *)linkArray withIdentifier:(NSString *)identifier{
7
8     self = [super init];
9     if (self) {
10
11         self.imgLinkArray = linkArray;
12         self.identifier   = identifier;
13     }
14
15     return self;
16 }
17
18 - (id)imgLinkAtIndexPath:(NSIndexPath *)indexPath {
19
20     return self.imgLinkArray[indexPath.row];
21 }
22
23 #pragma mark - CollectionView dataSource Methods
24 - (NSInteger)collectionView:(UICollectionView *)collectionView
25      numberOfItemsInSection:(NSInteger)section {
26
27     return self.imgLinkArray.count;
28 }
29
30
31 - (__kindof UICollectionViewCell *)collectionView:(UICollectionView *)collectionView
32                            cellForItemAtIndexPath:(NSIndexPath *)indexPath {
33
34     ShowPhotoCollectionViewCell *cell = \
35     [collectionView dequeueReusableCellWithReuseIdentifier:self.identifier
36                                               forIndexPath:indexPath];
37     [cell configCellWithImageLink:[self imgLinkAtIndexPath:indexPath]
38                         withTitle:\
39      [NSString stringWithFormat:@"%d/%d", indexPath.row + 1 , self.imgLinkArray.count]];
40
41     return cell;
42 }
43
44 @end

下面是在Controller中的使用方法

1 //创建CollectionView
2 - (void)createCollectionView {
3
4     self.dataSource = ({
5
6         PhotoDataSource *dataSource = [[PhotoDataSource alloc] \
7                                        initWithImageLinkArray:self.imglinkArray
8                                                withIdentifier:PHOTOCELLIDENTIFIER];
9
10         dataSource;
11     });
12
13     self.myCollectionView = ({
14
15         UICollectionViewFlowLayout *layout = [[UICollectionViewFlowLayout alloc] init];
16         [layout setScrollDirection:UICollectionViewScrollDirectionHorizontal];
17
18         UICollectionView *collection       = [[UICollectionView alloc] initWithFrame:\
19                         CGRectMake(0, 0, SCREEN_WIDTH, SCREEN_HEIGHT) collectionViewLayout:layout];
20
21         [collection registerClass:[PhotoCollectionViewCell class]
22                                                     forCellWithReuseIdentifier:PHOTOCELLIDENTIFIER];
23
24         collection.showsHorizontalScrollIndicator = NO;
25         collection.dataSource                     = self.dataSource;
26         collection.delegate                       = self;
27
28         collection;
29     });
30
31     [self.view addSubview:self.myCollectionView];
32 }