iphone – 控制台错误：必须使用非零布局参数初始化UICollection

当我使用此代码运行应用程序时：

-(NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView {

        return 1;

    }

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

        return [self.array count];

    }

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

        CollectionCell *aCell = (CollectionCell *)[collectionView dequeueReusableCellWithReuseIdentifier:@"myCell" forIndexPath:indexPath];

        aCell.title.text = self.array[indexPath.row];

        return aCell;

    }

    - (void)viewDidLoad
    {
        [super viewDidLoad];

        self.array = @[@"First",@"Second",@"Thirth",@"Fourth"];

    }

而在.h：

@property (strong,nonatomic) NSArray *array;

在控制台中,我收到以下错误：

Terminating app due to uncaught exception 'NSInvalidArgumentException',reason: 'UICollectionView must be initialized with a non-nil layout parameter'

我没有使用故事板,自定义了CollectionView你可以在这里看到：

有没有人有任何想法,为什么我收到此错误？一切都是受欢迎的！

编辑：

- (void)viewDidLoad
{
    [super viewDidLoad];

    self.array = @[@"First",@"Fourth"];

    [self.collectionView registerClass:[UICollectionViewCell class] forCellWithReuseIdentifier:@"myCell"];

    UICollectionViewFlowLayout *flow = [[UICollectionViewFlowLayout alloc] init];
    [flow setItemSize:CGSizeMake(60,60)];
    [flow setScrollDirection:UICollectionViewScrollDirectionVertical];

    [self.collectionView setCollectionViewLayout:flow];

}