NSArray有对象但UICollectionView显示为空

Question

我一直在这个项目上工作，以扩大我的投资组合。我还是比较新的Objective-C，所以帮助将不胜感激！

我一直在修改这段代码几天。我知道这些标签是有用的，因为我能够让所有的单元显示相同的信息（不是理想的结果）。这可能是我的阵列没有存储所有对象的错误。

下面是我的UIViewController的代码;

最初的问题

所以我已经证实了的NSLog，显示8个目标这是我的目标。

@interface YourDowey() 

@property (nonatomic, strong) NSMutableArray *eventTitleArray; 
@property (nonatomic, strong) NSMutableArray *eventLocationArray; 
@property (nonatomic, strong) NSMutableArray *eventIconArray; 
@property (nonatomic, strong) NSMutableArray *eventPriceArray; 
@property (nonatomic, strong) NSMutableArray *eventTypeArray; 


@end 

@implementation YourDowey 

- (void)viewDidLoad { 
[super viewDidLoad]; 

NSMutableArray *eventTitleArray = [[NSMutableArray alloc]initWithCapacity:8]; 
NSMutableArray *eventLocationArray = [[NSMutableArray alloc]initWithCapacity:8]; 
NSMutableArray *eventIconArray = [[NSMutableArray alloc]initWithCapacity:8]; 
NSMutableArray *eventPriceArray = [[NSMutableArray alloc]initWithCapacity:8]; 
NSMutableArray *eventTypeArray = [[NSMutableArray alloc]initWithCapacity:8]; 

for (NSUInteger index = 0; (index < 8) ; index++){ 

    EventsList *eventList = [[EventsList alloc] initWithIndex:index]; 

    NSString *individualEventTitle = eventList.eventTitle; 
    NSString *individualEventLocation = eventList.eventLocation; 

    NSString *individualEventIcon = eventList.eventIcon; 
    NSString *individualEventPrice = eventList.eventPrice; 
    NSString *individualEventType = eventList.eventType; 

    [eventTitleArray addObject:individualEventTitle]; 
    [eventLocationArray addObject:individualEventLocation]; 
    [eventIconArray addObject:individualEventIcon]; 
    [eventPriceArray addObject:individualEventPrice]; 
    [eventTypeArray addObject:individualEventType]; 

    } 
NSLog(@"Events: %@", eventTitleArray); 
NSLog(@"Number of objects: %lu", (unsigned long)[eventTitleArray count]); 
} 

然而，当我使用的决定多少个单体电池我想，通过阵列计数方法我实现对UICollectionView 0细胞？当NSLog确认有8个对象时，这是令人困惑的。

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

这是相对于UIViewControllerCell代码和分配阵列到细胞各自UIObject类（标签/图像）。

-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath{ 
EventsCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"eventsCell" forIndexPath:indexPath]; 

NSString *imagesString = [self.eventIconArray objectAtIndex:indexPath.row]; 

cell.eventImage.image = [UIImage imageNamed:imagesString]; 
cell.eventTitle.text = [self.eventTitleArray objectAtIndex:indexPath.row]; 
cell.eventLocation.text = [self.eventLocationArray objectAtIndex:indexPath.row]; 
cell.eventPrice.text = [self.eventPriceArray objectAtIndex:indexPath.row]; 
cell.eventType.text = [self.eventTypeArray objectAtIndex:indexPath.row]; 

return cell; 
} 

我的怀疑

我试图感知问题背后的逻辑。而且我不确定它是否在viewDidLoad之前调用了UICollectionView方法？我的意思是在viewDidLoad数组中显然通过NSLog有8个对象，但是当修改相对于UICollectionView/Cells的方法时，它们似乎是空的？

修订

下面是其涉及从该阵列是越来越分配信息到字典的代码;

EventsLibrary.h

#import <Foundation/Foundation.h> 

extern NSString *const kTitle; 
extern NSString *const kLocation; 
extern NSString *const kPrice; 
extern NSString *const kIcon; 
extern NSString *const kLargeIcon; 
extern NSString *const kType; 

@interface EventsLibrary : NSObject 

@property (strong, nonatomic) NSArray *library; 

@end 

EventsLibrary.m

#import "EventsLibrary.h" 

NSString *const kTitle = @"title"; 
NSString *const kLocation = @"location"; 
NSString *const kPrice = @"price"; 
NSString *const kIcon = @"icon"; 
NSString *const kLargeIcon = @"largeIcon"; 
NSString *const kType = @"type"; 

@implementation EventsLibrary 

-(instancetype) init{ 
self = [super init]; 
if (self) { 
    _library  = @[  @{ kTitle:@"iCafe de Paris", 
            kLocation:@"International Drive", 
            kPrice:@"$10", 
            kIcon:@"iCafe.png", 
            kLargeIcon:@"iCafeLrg.png", 
            kType:@"Food"}, 

           @{ kTitle:@"Orlando's Museum of Art", 
            kLocation:@"N Mills Ave", 
            kPrice:@"$20", 
            kIcon:@"Museum.png", 
            kLargeIcon:@"MuseumLrg.png", 
            kType:@"Art"}, 

           @{ kTitle:@"Club 180", 
            kLocation:@"W Church Street", 
            kPrice:@"$20", 
            kIcon:@"Club180.png", 
            kLargeIcon:@"Club180Lrg.png", 
            kType:@"NightLife"}, 

           @{ kTitle:@"Wekiva Springs", 
            kLocation:@"Wekiva Circle, Apopka", 
            kPrice:@"$5", 
            kIcon:@"Wekiva.png", 
            kLargeIcon:@"WekivaLrg.png", 
            kType:@"Nature"}, 

           @{ kTitle:@"Kings Bowling", 
            kLocation:@"International Drive", 
            kPrice:@"$10", 
            kIcon:@"Kings.png", 
            kLargeIcon:@"KingLrg.png", 
            kType:@"Sports"}, 

           @{ kTitle:@"Pirate's Cove Mini Golf", 
            kLocation:@"International Drive", 
            kPrice:@"$15", 
            kIcon:@"PiratesGolf.png", 
            kLargeIcon:@"PiratesGolfLrg.png", 
            kType:@"Sports"}, 

           @{ kTitle:@"Cobb's Plaza Cinema", 
            kLocation:@"S Orange Ave", 
            kPrice:@"$8", 
            kIcon:@"Cobbs.png", 
            kLargeIcon:@"CobbsLrg.png", 
            kType:@"Art"}, 

           @{ kTitle:@"Mango's Cafe", 
            kLocation:@"International Drive", 
            kPrice:@"FREE", 
            kIcon:@"Mangos.png", 
            kLargeIcon:@"MangosLrg.png", 
            kType:@"Food"} 
          ]; 
} 
return self; 
} 

@end 

EventsList.h

#import <Foundation/Foundation.h> 
#import <UIKit/UIKit.h> 
#import "EventsLibrary.h" 

@interface EventsList : NSObject 

@property (strong, nonatomic) NSString *eventTitle; 
@property (strong, nonatomic) NSString *eventLocation; 
@property (strong, nonatomic) NSString *eventPrice; 
@property (strong, nonatomic) NSString *eventIcon; 
@property (strong, nonatomic) NSString *eventIconLarge; 
@property (strong, nonatomic) NSString *eventType; 

- (instancetype)initWithIndex:(NSUInteger)index; 

@end 

EventsList.m

#import "EventsList.h" 

@implementation EventsList 

-(instancetype)initWithIndex:(NSUInteger)index{ 
self = [super init]; 
if (self) { 

    EventsLibrary *eventsLibrary = [[EventsLibrary alloc]init]; 
    NSArray *library = eventsLibrary.library; 

    NSDictionary *eventsDictionary = library[index]; 

    _eventTitle = [eventsDictionary objectForKey:kTitle]; 
    _eventLocation = [eventsDictionary objectForKey:kLocation]; 
    _eventPrice = [eventsDictionary objectForKey:kPrice]; 

    NSString *iconName = [eventsDictionary objectForKey:kIcon]; 
    _eventIcon = [UIImage imageNamed:iconName]; 

    NSString *largeIconName = [eventsDictionary objectForKey:kLargeIcon]; 
    _eventIconLarge = [UIImage imageNamed:largeIconName]; 

    _eventType = [eventsDictionary objectForKey:kType]; 
} 
return self; 
} 

@end 

Answer 1

我想通了你的问题。

- (void)viewDidLoad { 
[super viewDidLoad]; 

NSMutableArray *eventTitleArray = [[NSMutableArray alloc]initWithCapacity:8]; 
NSMutableArray *eventLocationArray = [[NSMutableArray alloc]initWithCapacity:8]; 
NSMutableArray *eventIconArray = [[NSMutableArray alloc]initWithCapacity:8]; 
NSMutableArray *eventPriceArray = [[NSMutableArray alloc]initWithCapacity:8]; 
NSMutableArray *eventTypeArray = [[NSMutableArray alloc]initWithCapacity:8]; 
... 
} 

请注意，您再次重新声明所有的变量在viewDidLoad功能。这会隐藏你的属性，因此它们永远不会被初始化。一旦在类定义中声明它们，您可以改为使用self.eventTitleArray = [[NSMutableArray alloc] init...]。

我建议是这样的：

NSMutableArray *eventArray; //One single array for all 

- (void)viewDidLoad { 
[super viewDidLoad]; 

self.eventArray = [[NSMutableArray alloc]initWithCapacity:8]; 

for (NSUInteger index = 0; (index < 8) ; index++){ 

    EventsList *eventList = [[EventsList alloc] initWithIndex:index]; 

    NSString *individualEventTitle = eventList.eventTitle; 
    NSString *individualEventLocation = eventList.eventLocation; 

    NSString *individualEventIcon = eventList.eventIcon; 
    NSString *individualEventPrice = eventList.eventPrice; 
    NSString *individualEventType = eventList.eventType; 

    NSDictionary *eventDictionary = [[NSDictionary alloc] initWithObjectsAndKeys: eventList.eventTitle, @"Title", eventList.eventLocation, @"Location", eventList.eventIcon, @"Icon", eventList.eventPrice, @"Price, eventList.eventType, @"Type", nil]; 

    [eventArray addObject:eventDictionary]; 

    } 
NSLog(@"Events: %@", eventArray); 
NSLog(@"Number of objects: %lu", (unsigned long)[eventArray count]); 
} 

然后，您可以使用[NSDictionary objectForKey:@""]在将来某个时间访问所需的数据点。这也意味着，您只需管理一个包含所有信息的阵列。定性地说，它不会影响你的程序逻辑