在.h中声明

@property (nonatomic, strong) UICollectionView *myCollecionView;



遵循CollectionView协议

<UICollectionViewDataSource, UICollectionViewDelegateFlowLayout>


.m文件中实现

@implementation ViewController


- (void)viewDidLoad {

[super viewDidLoad];

// Do any additional setup after loading the view, typically from a nib.

_collectionView.delegate = self;

_collectionView.dataSource = self;

//创建布局对象

UICollectionViewFlowLayout *flowLayout = [[UICollectionViewFlowLayout alloc] init];

//itme与item之间的最小间距--默认是10

// flowLayout.minimumInteritemSpacing = 110;

// flowLayout.minimumLineSpacing = 100;

// flowLayout.itemSize = CGSizeMake(80, 80);

// flowLayout.scrollDirection = UICollectionViewScrollDirectionHorizontal;

//初始化CollectionView

_myCollecionView = [[UICollectionView alloc] initWithFrame:CGRectMake(0, 667 - 284, 375, 284) collectionViewLayout:flowLayout];

_myCollecionView.tag = 200;

_myCollecionView.delegate = self;

_myCollecionView.dataSource = self;

_myCollecionView.backgroundColor = [UIColor redColor];

[self.view addSubview:_myCollecionView];

//注册单元格

[_myCollecionView registerClass:[UICollectionViewCell class] forCellWithReuseIdentifier:@"myCollecionViewCell"];

}



#pragma mark -UICollectionViewDataSource

//指定组的个数

- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView

{

return 2;

}



//指定单元格的个数

- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section

{

return 21;

}



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

{

if (collectionView.tag == 100) {

UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"collectionViewCell" forIndexPath:indexPath];

cell.backgroundColor = [UIColor colorWithRed:arc4random() % 10 * 0.1 green:arc4random() % 10 * 0.1 blue:arc4random() % 10 * 0.1 alpha:1];

return cell;

}else if (collectionView.tag == 200) {

UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"myCollecionViewCell" forIndexPath:indexPath];

cell.backgroundColor = [UIColor colorWithRed:arc4random() % 10 * 0.1 green:arc4random() % 10 * 0.1 blue:arc4random() % 10 * 0.1 alpha:1];

return cell;

}

return nil;

}



//动态地设置单元格的尺寸

- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath

{

return CGSizeMake(80, arc4random() % 80);

}





@end