UICollectionViewController以非零布局参数错误编程崩溃

Question

我正在以UICollectionViewController编程方式创建.不,我不想像每个教程那样使用IB和Storyboard.我只想使用普通代码.

这是我在我的viewDidLoad:

// UICollectionView
    UICollectionViewFlowLayout *aFlowLayout = [[UICollectionViewFlowLayout alloc] init];
    [aFlowLayout setItemSize:CGSizeMake(200, 140)];
    [aFlowLayout setScrollDirection:UICollectionViewScrollDirectionVertical];
    self.collectionView = [[UICollectionView alloc] initWithFrame:self.view.frame collectionViewLayout:aFlowLayout];
    [self.collectionView setDelegate:self];
    [self.collectionView setDataSource:self];
    self.collectionView.backgroundColor = [UIColor clearColor];
    [self.collectionView setAutoresizingMask:UIViewAutoresizingFlexibleHeight | UIViewAutoresizingFlexibleLeftMargin | UIViewAutoresizingFlexibleRightMargin | UIViewAutoresizingFlexibleWidth];
    [self.collectionView registerClass:[PUCImageGridCell class] forCellWithReuseIdentifier:CollectionViewCellIdentifier];

我已经实现了所需的委托方法,但仍然会收到此错误:

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

Answer 1

这是我用来初始化UICollectionViewController的方法:

- (id)initWithCollectionViewLayout:(UICollectionViewLayout *)layout

您不需要实例化collectionView控制器将为您执行此操作.调用后设置框架,或者您可以覆盖并设置内部框架:

- (id)initWithCollectionViewLayout:(UICollectionViewLayout *)layout{
     self = [super initWithCollectionViewLayout:layout];
     if (self) {
         // additional setup here if required.
     }
     return self;
}

我更喜欢使用autolayout约束.