Ios UICollectionViewController黑屏

我试图显示我的收藏视图，但我得到的只是一个黑屏。我知道我遗漏了什么，但我似乎找不到它是什么

#import "StoreCollectionViewController.h"
#import "StoreItemCell.h"

@interface StoreCollectionViewController ()

@property (nonatomic, strong) NSMutableArray *productsArray;
@property (nonatomic, strong) UIActivityIndicatorView *loadingIndicator;

@end

@implementation StoreCollectionViewController

static NSString * const reuseIdentifier = @"Cell";

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self)
    {
        self.productsArray = [[NSMutableArray alloc]init];
    }
    return self;
}

- (void)viewDidLoad {
    [super viewDidLoad];

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

    // Register cell classes
    [self.collectionView registerClass:[StoreItemCell class] forCellWithReuseIdentifier:reuseIdentifier];

    CGFloat width = CGRectGetWidth(self.view.bounds);
    CGFloat height = CGRectGetHeight(self.view.bounds);

    self.loadingIndicator = [[UIActivityIndicatorView alloc]initWithFrame:CGRectMake(width / 2, height / 2, 37, 37)];
    self.loadingIndicator.center = CGPointMake(width / 2, height / 2 - 37);
    self.loadingIndicator.autoresizingMask = (UIViewAutoresizingFlexibleRightMargin | UIViewAutoresizingFlexibleLeftMargin | UIViewAutoresizingFlexibleBottomMargin | UIViewAutoresizingFlexibleTopMargin);
    self.loadingIndicator.activityIndicatorViewStyle = UIActivityIndicatorViewStyleWhiteLarge;
    self.loadingIndicator.hidesWhenStopped = YES;
    [self.view addSubview:self.loadingIndicator];
    [self.loadingIndicator startAnimating];

    [self dispatch];
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

- (void)dispatch {
    NSURL *url = [NSURL URLWithString:@"http://api.bigcartel.com/littleheart/products.json"];
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        NSData *data = [NSData dataWithContentsOfURL:url];

        dispatch_async(dispatch_get_main_queue(), ^{
            if (data == nil) {
                NSLog(@"data is nil");
                UIAlertView *nilDataAlert = [[UIAlertView alloc]initWithTitle:@"" message:@"There is nothing here!" delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil, nil];
                [nilDataAlert show];

                [self.loadingIndicator stopAnimating];
            }
            else {
                [self performSelectorOnMainThread:@selector(getProducts:) withObject:data waitUntilDone:YES];
            }
        });
    });
}

- (void)getProducts:(NSData *)responseData {
    NSError *error;
    NSMutableArray *responseArray = [NSJSONSerialization
                                     JSONObjectWithData:responseData
                                     options:kNilOptions
                                     error:&error];

    for (NSDictionary *productDictionary in responseArray) {
        [self.productsArray addObject:productDictionary];
    }

    [self.collectionView reloadData];
    [self.loadingIndicator stopAnimating];
}

#pragma mark <UICollectionViewDataSource>

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

- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section {
    return self.productsArray.count;
}

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
    StoreItemCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:reuseIdentifier forIndexPath:indexPath];

    // Configure the cell
    NSString *productName = [[self.productsArray objectAtIndex:indexPath.row]objectForKey:@"name"];
    cell.itemNameLabel.text = productName;

    return cell;
}

#pragma mark <UICollectionViewDelegate>

- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath {

}

@end

#导入“StoreCollectionViewController.h”
#导入“StoreItemCell.h”
@接口StoreCollectionViewController（）
@属性（非原子，强）NSMutableArray*productsArray；
@属性（非原子，强）UIActivityIndicatorView*加载指示器；
@结束
@实现StoreCollectionViewController
静态NSString*const reuseIdentifier=@“Cell”；
-（id）initWithNibName:（NSString*）nibNameOrNil bundle:（NSBundle*）nibBundleOrNil
{
self=[super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]；
如果（自我）
{
self.productsArray=[[NSMutableArray alloc]init]；
}
回归自我；
}
-（无效）viewDidLoad{
[超级视图下载]；
self.collectionView.delegate=self；
self.collectionView.dataSource=self；
//注册单元类
[self.collectionView注册表类：[StoreItemCell类]forCellWithReuseIdentifier:reuseIdentifier]；
CGFloat width=CGRectGetWidth（self.view.bounds）；
CGFloat height=CGRectGetHeight（self.view.bounds）；
self.loadingIndicator=[[UIActivityIndicatorView alloc]initWithFrame:CGRectMake（宽度/2，高度/2，37，37）]；
self.loadingIndicator.center=CGPointMake（宽/2，高/2-37）；
self.loadingIndicator.autoresizingMask=（UIViewAutoresizingFlexibleRightMargin | uiviewautoresizingflexibleleleftmargin | uiviewautoresizingflexiblebtotommargin | uiviewautoresizingflexibleptopmargin | uiviewautoresizingflexibleptommargin；
self.loadingIndicator.activityIndicatorViewStyle=UIActivityIndicatorViewStyleWhiteLarge；
self.loadingIndicator.hidesWhenStopped=是；
[self.view addSubview:self.loadingIndicator]；
[自加载指示器启动激活]；
[自行发送]；
}
-（无效）未收到记忆警告{
[超级记忆警告]；
//处置所有可以重新创建的资源。
}
-（无效）派遣{
NSURL*url=[NSURL URLWithString:@”http://api.bigcartel.com/littleheart/products.json"];
调度异步（调度获取全局队列（调度队列优先级默认为0）^{
NSData*data=[NSData dataWithContentsOfURL:url]；
dispatch\u async（dispatch\u get\u main\u queue（）^{
如果（数据==nil）{
NSLog（“数据为零”）；
UIAlertView*nilDataAlert=[[UIAlertView alloc]initWithTitle:@”“消息：@“这里什么都没有！”委托：自取消按钮：@“确定”其他按钮：nil，nil]；
[nilDataAlert show]；
[自加载指示器停止设置动画]；
}
否则{
[self-performSelectorOnMainThread:@selector（getProducts:）withObject:data waitUntilDone:YES]；
}
});
});
}
-（无效）getProducts:（NSData*）responseData{
n错误*错误；
NSMutableArray*responseArray=[NSJSONSerialization
JSONObjectWithData:responseData
选项：针织品
错误：&错误]；
对于（NSDictionary*productDictionary in responseArray）{
[self.productsArray addObject:productDictionary]；
}
[self.collectionView-reloadData]；
[自加载指示器停止设置动画]；
}
#布拉格标记
-（NSInteger）collectionView中的节数：（UICollectionView*）collectionView{
返回1；
}
-（NSInteger）collectionView:（UICollectionView*）collectionView项目编号截面：（NSInteger）截面{
返回self.productsArray.count；
}
-（UICollectionViewCell*）collectionView:（UICollectionView*）collectionView cellForItemAtIndexPath:（NSIndexPath*）indexPath{
StoreItemCell*cell=[collectionView dequeueReusableCellWithReuseIdentifier:reuseIdentifier forIndexPath:indexPath]；
//配置单元格
NSString*productName=[[self.productsArray objectAtIndex:indexath.row]objectForKey:@“name”]；
cell.itemNameLabel.text=productName；
返回单元；
}
#布拉格标记
-（void）collectionView:（UICollectionView*）collectionView didSelectItemAtIndexPath:（NSIndexPath*）indexPath{
}
@结束

问题不在于你是否在收藏中加载了一些东西，而在于更一般的东西。这就是collectionViewController是否实例化以及是否正确加载。

---

所有根视图控制器视图都具有默认的白色。但是UIWindow类具有默认的黑色。如果您看到黑色，我怀疑窗口是空的，

您是否使用了UICollectionViewDelegateFlowLayout方法来调整单元格大小

像这样（这是在Swift中，使用Objective-C syntex）

---

确保productsArray不为空或为零。如果是，则不会生成任何单元格。

func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAtIndexPath indexPath: NSIndexPath) -> CGSize
{
    return CGSizeMake(50,120); //use whatever you wants.
}