Question

在我的应用程序中，我基于数据集构建了一个集合视图。当我执行全新安装时，所有标题标题都显示正确。重新打开应用程序后，第一个标题标题消失。在viewWillAppear方法中调用reloadData并不能解决问题。

我的代码：

    #import "ChapterViewController.h"
#import "XMLParser.h"
#import "ChapterStore.h"
#import "Chapter.h"
#import "Section.h"
#import "Word.h"
#import "ChapterViewCell.h"

@interface ChapterViewController ()
@property (nonatomic, strong) IBOutlet UICollectionView *collectionView;
@property (nonatomic, strong) NSArray *dataArray;

@end

@implementation ChapterViewController

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {

        [[self navigationItem] setTitle:@"Chapters"];
        self.navigationController.navigationBar.translucent = NO;
        NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];

        if ( ![userDefaults valueForKey:@"version"] )
        {
            [[ChapterStore sharedStore] doParse];

            [self spaceTrimmer:[ChapterStore sharedStore]];


            // Adding version number to NSUserDefaults for first version:
            [userDefaults setFloat:[[[[NSBundle mainBundle] infoDictionary] objectForKey:@"CFBundleVersion"] floatValue] forKey:@"version"];
        }


        if ([[NSUserDefaults standardUserDefaults] floatForKey:@"version"] == [[[[NSBundle mainBundle] infoDictionary] objectForKey:@"CFBundleVersion"] floatValue] )
        {
            /// Same Version so dont run the function
        }
        else
        {
            // Call Your Function;

            // Update version number to NSUserDefaults for other versions:
            [userDefaults setFloat:[[[[NSBundle mainBundle] infoDictionary] objectForKey:@"CFBundleVersion"] floatValue] forKey:@"version"];
        }

    }
    return self;
}

- (void)viewWillAppear:(BOOL)animated {
    [super viewWillAppear:YES];
    [[self collectionView] reloadData];    
}

- (NSInteger)numberOfChapters {
    return [[[ChapterStore sharedStore] allChapters] count];
}

- (void)viewDidLoad
{
    [super viewDidLoad];

    NSMutableArray *chapters = [[NSMutableArray alloc] init];
    for (int i = 0; i < [self numberOfChapters]; i++) {
        [chapters addObject:[[[ChapterStore sharedStore] allChapters] objectAtIndex:i]];
    }
    if ([self respondsToSelector:@selector(edgesForExtendedLayout)])
        self.edgesForExtendedLayout = UIRectEdgeNone;

    self.dataArray = chapters;

    UINib *cellNib = [UINib nibWithNibName:@"ChapterViewCell" bundle:nil];
    [self.collectionView registerNib:cellNib forCellWithReuseIdentifier:@"cvCell"];
    [self.collectionView registerNib:[UINib nibWithNibName:@"ChapterViewHeader" bundle:nil] forSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:@"cvHeader"];


    UICollectionViewFlowLayout *flowLayout = [[UICollectionViewFlowLayout alloc] init];
    [flowLayout setItemSize:CGSizeMake(159, 159)];
    [flowLayout setScrollDirection:UICollectionViewScrollDirectionVertical];
    [flowLayout setMinimumInteritemSpacing:2];
    [flowLayout setMinimumLineSpacing:2];
    [flowLayout setHeaderReferenceSize:CGSizeMake(0, 50)];


    [self.collectionView setCollectionViewLayout:flowLayout];

}


- (UICollectionReusableView *)collectionView:(UICollectionView *)collectionView viewForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath {

    UICollectionReusableView *header = [collectionView dequeueReusableSupplementaryViewOfKind:kind withReuseIdentifier:@"cvHeader" forIndexPath:indexPath];

    Chapter *data = [self.dataArray objectAtIndex:indexPath.section];

    NSString *chapterName = [data CHAPTER_NAME];

    UILabel *titleLabel = (UILabel *)[header viewWithTag:99];

    [titleLabel setText:chapterName];

    return header;
}

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

    Chapter *data = [self.dataArray objectAtIndex:indexPath.section];

    Section *section = [[data sections]objectAtIndex:indexPath.row];

    NSString *cellData = [section SECTION_NAME];

    static NSString *cellIdentifier = @"cvCell";

    ChapterViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:cellIdentifier forIndexPath:indexPath];
    int i = [indexPath indexAtPosition:0] + 1;
    int j = [indexPath indexAtPosition:1] + 1;

    NSString *imageName = [NSString stringWithFormat:@"c%ds%d.jpg", i,j];

    UIImage *image = [UIImage imageNamed:imageName];

    [cell setController:self];
    [cell setCollectionView:collectionView];

    [[cell sectionLabel] setText:cellData];

    [[cell imageView]setImage:image];

    return cell;

}

-(NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView
{
    return [self.dataArray count];
}

-(NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
    Chapter *sectionArray = [self.dataArray objectAtIndex:section];
    return [[sectionArray sections] count];
}

Answer 1

这似乎是缓存或IOS 7升级问题。我完全卸载了应用程序，重新启动了xcode和模拟器，问题现在已经消失。

UICollectionView标题标题消失后

1 个答案: