UICollectionView中不显示(UICollectionView Not Appearin

我试图建立UICollectionView 编程在延伸我的视图控制器UIViewController 。出于某种原因，我的收藏查看没有显示出来的。下面是我。

为什么没有出现？我挂钩它的委托和数据源，将其添加为一个子视图self.view 。现在缺少的在我的代码？

在我.h文件：

@interface MainViewController : UIViewController
{
    @private
    UICollectionView *_collectionView;
    NSMutableArray *_results; // data source array
}
@end

在我.m文件：

@interface MainViewController () <UICollectionViewDataSource, UICollectionViewDelegateFlowLayout>
@property (nonatomic, retain) UICollectionView *collectionView;
@property (nonatomic, retain) NSMutableArray *results;
@end

@implementation MainViewController

@synthesize collectionView = _collectionView;
@synthesize results = _results;

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // some init stuff - nothing to do with collection view.
    }

    return self;
}

- (void)loadView
{
    self.results = [NSMutableArray array];
    UIImage *image1 = [UIImage imageNamed:@"img1.jpg"];
    UIImage *image2 = [UIImage imageNamed:@"img2.jpg"];
    [self.results addObject:image1];
    [self.results addObject:image2];

    self.collectionView.dataSource = self;
    self.collectionView.delegate = self;

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

    UICollectionView *collectionView = [[UICollectionView alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height) collectionViewLayout:flowLayout];
    self.collectionView = collectionView;

    [self.view addSubview:self.collectionView];

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

}

- (NSInteger)collectionView:(UICollectionView *)view numberOfItemsInSection:(NSInteger)section
{
    return [self.results count];
}

- (NSInteger)numberOfSectionsInCollectionView: (UICollectionView *)collectionView
{
    return 1;
}

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
    UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"Cell" forIndexPath:indexPath];
    cell.backgroundColor = [UIColor colorWithPatternImage:[self.results objectAtIndex:indexPath.row]];
    return cell;
}


- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath {
    UIImage *image = [self.results objectAtIndex:indexPath.row];    
    return CGSizeMake(image.size.width, image.size.height);
}

- (UIEdgeInsets)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout insetForSectionAtIndex:(NSInteger)section {
    return UIEdgeInsetsMake(50, 20, 50, 20);
}

Answer 1:

根据你不应该直接调用的loadView的文档 - 我的错误尝试，除非我改变了的loadView方法viewDidLoad中运行代码。要获取数据源和委托方法来运行，我搬到了线的委托和数据源设置为自下方，您可以设置self.collectionView =的CollectionView

    self.collectionView = collectionView;
    self.collectionView.dataSource = self;
    self.collectionView.delegate = self;

Answer 2:

您numberOfSectionsInCollectionView:返回0 。对于一款集合视图，您应该返回1或只是没有实现此方法。

此外，我不能看到你分配/初始化self.collectionView 。

Answer 3:

我结束了继承UICollectionViewController而不是UIViewController和不断变化的init方法来：

- (id)initWithCollectionViewLayout:(UICollectionViewLayout *)layout

和它的工作。

Answer 4:

你只需要你的CollectionView代表，以及数据源绑定到的ViewController在故事板。在这里输入图像描述