[ios]如何分组具有 UICollectionReusableView （使用 JSON） 的单元格

我填充一个 Rails 应用程序 (http://obscure-lake-7450.herokuapp.com/upcoming.json) 从 JSON 与我的应用程序。在我的 Rails 应用程序中的每一个岗位有"发布日期"，和他们按 (基本上每个星期有释放某些运动鞋) 发布日期分组。我想要能做同样的事情在我的应用程序，但很难做的。

我的演示图板上有一个集合可重用视图与 UICollectionReusableView 类和标识符称为"releasesGroup"，我也有一个连接到 UICollectionReusableView 称为"releasesHeader"的标签。

我也想要显示对应的日期在页眉中，像这样：

视图控制器

- (void)viewDidLoad
{
    [super viewDidLoad];

    NSURL *upcomingReleaseURL = [NSURL URLWithString:@"http://obscure-lake-7450.herokuapp.com/upcoming.json"];

    NSData *jsonData = [NSData dataWithContentsOfURL:upcomingReleaseURL];

    NSError *error = nil;

    NSDictionary *dataDictionary = [NSJSONSerialization JSONObjectWithData:jsonData options:0 error:&error];

    self.upcomingReleases = [NSMutableArray array];

    NSArray *upcomingReleasesArray = [dataDictionary objectForKey:@"upcoming_releases"];

    for (NSDictionary *upcomingReleaseDictionary in upcomingReleasesArray) {
        UpcomingRelease *upcomingRelease = [UpcomingRelease upcomingReleaseWithName:[upcomingReleaseDictionary objectForKey:@"release_name"]];
        upcomingRelease.release_date = [upcomingReleaseDictionary objectForKey:@"release_date"];
        [self.upcomingReleases addObject:upcomingRelease];
    }

    [self.collectionView registerClass:[UpcomingReleaseCell class] forCellWithReuseIdentifier:@"UpcomingReleaseCell"];
}

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

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

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
    static NSString *identifier = @"Cell";

    UpcomingReleaseCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:identifier forIndexPath:indexPath];

    UpcomingRelease *upcomingRelease = [self.upcomingReleases objectAtIndex:indexPath.row];

    cell.release_name.text = upcomingRelease.release_name;

    return cell;
}

我的 UICollectionReusableView

@interface ReleasesGroup : UICollectionReusableView
@property (weak, nonatomic) IBOutlet UILabel *releasesHeader;
@end


@implementation ReleasesGroup
- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        // Initialization code
    }
    return self;
}
@end

谢谢你。

编辑：

我的继续

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    if ([[segue identifier] isEqualToString:@"showRelease"])
    {
        NSIndexPath *selectedIndexPath = [[self.collectionView indexPathsForSelectedItems] objectAtIndex:0];
        ReleaseViewController *releaseViewController = [segue destinationViewController];
        releaseViewController.singleRelease = self.upcomingReleases[selectedIndexPath.row];
    }
}

ReleaseViewController.h

#import <UIKit/UIKit.h>
#import "UpcomingRelease.h"

@interface ReleaseViewController : UIViewController

@property (strong, nonatomic) UpcomingRelease *singleRelease;
@property (weak, nonatomic) IBOutlet UILabel *release_name;
@property (weak, nonatomic) IBOutlet UILabel *release_price;
@property (weak, nonatomic) IBOutlet UILabel *release_colorway;
@property (weak, nonatomic) IBOutlet UILabel *release_date;
@property (weak, nonatomic) IBOutlet UIImageView *thumb;

@end

ReleaseViewController.m

#import "ReleaseViewController.h"

@interface ReleaseViewController ()

@end

@implementation ReleaseViewController

@synthesize singleRelease = _singleRelease;
@synthesize release_name = _release_name;
@synthesize release_price = _release_price;
@synthesize release_colorway = _release_colorway;
@synthesize release_date = _release_date;
@synthesize thumb = _thumb;

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

- (void)viewDidLoad
{
    [super viewDidLoad];

    NSString *thumbURL = nil;

    if ([_singleRelease.images isKindOfClass:[NSArray class]] && [_singleRelease.images count])
        thumbURL = [[[[[_singleRelease.images objectAtIndex:0] objectForKey:@"image_file"] objectForKey:@"image_file"] objectForKey:@"medium"] objectForKey:@"url"];

    if (thumbURL)
    {
        NSData *imageData = [NSData dataWithContentsOfURL:[NSURL URLWithString:thumbURL]];
        UIImage *image = [UIImage imageWithData:imageData];
        self.thumb.image = image;
    }
    else {
        self.thumb.image = [UIImage imageNamed:@"cover.png"];
    }

    self.release_name.text = self.singleRelease.release_name;
    self.release_price.text = [NSString stringWithFormat:@"$%@", _singleRelease.release_price];
    self.release_colorway.text = self.singleRelease.release_colorway;
    self.release_date.text = [NSString stringWithFormat:@"%@", _singleRelease.formattedDate];
}

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

@end

解决方法 1:

好的它会出现您错过了不少事。首先： 要组由天发布，你将需要某种日期操纵，在 viewDidLoad 方法中，你将需要已分组的 json 数据到"水桶"对应的发布日期。一旦您有这，剩下的就一块蛋糕。所以放到它上面：

首先，你需要一个属性在您的视图控制器包含的所有数据。就像这样:

@property (strong, nonatomic) NSDictionary *upReleases;
@property (strong, nonatomic) NSArray *releaseBuckets;

然后，在你 viewDidLoad 方法，您会需要填充这本词典：

- (void)viewDidLoad
{
    [super viewDidLoad];

    NSURL *upcomingReleaseURL = [NSURL URLWithString:@"http://obscure-lake-7450.herokuapp.com/upcoming.json"];

    NSData *jsonData = [NSData dataWithContentsOfURL:upcomingReleaseURL];

    NSError *error = nil;

    NSDictionary *dataDictionary = [NSJSONSerialization JSONObjectWithData:jsonData options:0 error:&error];

    NSArray *upcomingReleasesArray = [dataDictionary objectForKey:@"upcoming_releases"];

    //This is the dateFormatter we'll need to parse the release dates

    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setDateFormat:@"yyyy-MM-dd'T'HH:mm:ss.SSSv"];
    NSTimeZone *gmt = [NSTimeZone timeZoneWithAbbreviation:@"GMT"];
    [dateFormatter setTimeZone:gmt];
    [dateFormatter setLocale:[[NSLocale alloc] initWithLocaleIdentifier:@"en_GB"]]; //A bit of an overkill to avoid bugs on different locales

        //Temp array where we'll store the unsorted bucket dates
    NSMutableArray *buckets = [[NSMutableArray alloc] init];
    NSMutableDictionary *tmpDict = [[NSMutableDictionary alloc] init];

    for (NSDictionary *upcomingReleaseDictionary in upcomingReleasesArray) {

        //We find the release date from the string
        NSDate *releaseDate = [dateFormatter dateFromString:[upcomingReleaseDictionary objectForKey:@"release_date"]];

        //We create a new date that ignores everything that is not the actual day
        //(ignoring stuff like the time of the day)
        NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
        NSDateComponents *components =
        [gregorian components:(NSDayCalendarUnit | NSMonthCalendarUnit | NSYearCalendarUnit) fromDate:releaseDate];

        //This will represent our releases "bucket"
        NSDate *bucket = [gregorian dateFromComponents:components];

        //We get the existing objects in the bucket and update it with the latest addition
        NSMutableArray *releasesInBucket = [tmpDict objectForKey:bucket];           
        if (!releasesInBucket){
            releasesInBucket = [NSMutableArray array];
            [buckets addObject:bucket];
        }

        UpcomingRelease *upcomingRelease = [UpcomingRelease upcomingReleaseWithName:[upcomingReleaseDictionary objectForKey:@"release_name"]];
        upcomingRelease.release_date = [upcomingReleaseDictionary objectForKey:@"release_date"];
        [releasesInBucket addObject:upcomingRelease];
        [tmpDict setObject:releasesInBucket forKey:bucket];
    }

    [buckets sortUsingComparator:^NSComparisonResult(id obj1, id obj2) {
        NSDate* date1 = obj1;
        NSDate* date2 = obj2;
        //This will sort the dates in ascending order (earlier dates first)
        return [date1 compare:date2];       
        //Use [date2 compare:date1] if you want an descending order
    }];


    self.upReleases = [NSDictionary dictionaryWithDictionary:tmpDict];
    self.releaseBuckets = [NSArray arrayWithArray:buckets];

}

下一步，您需要有尽可能多的部分作为释放存储桶。一块蛋糕：

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

许多单元格每桶作为被释放在该日期的产品：

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

然后，您需要设置每节 （再次，一点点的操纵有必要你页眉节的正确格式的日期） 的标头：

-(UICollectionReusableView *)collectionView:(UICollectionView *)collectionView viewForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath
{
    ReleasesGroup* releaseGroup = [collectionView dequeueReusableSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:@"releasesGroup" forIndexPath:indexPath];

    //We tell the formatter to produce a date in the format "Name-of-the-month day"
    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setDateFormat:@"MMMM dd"];
    NSTimeZone *gmt = [NSTimeZone timeZoneWithAbbreviation:@"GMT"];
    [dateFormatter setTimeZone:gmt];
    [dateFormatter setLocale:[[NSLocale alloc] initWithLocaleIdentifier:@"en_GB"]];

    //We read the bucket date and feed it to the date formatter
    NSDate* bucketDate = self.releaseBuckets[indexPath.section];

    releaseGroup.releasesHeader.text = [[dateFormatter stringFromDate:bucketDate] uppercaseString];
    return releaseGroup;
}

最后，您需要安装的单个单元格：

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
    static NSString *identifier = @"Cell";

    UpcomingReleaseCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:identifier forIndexPath:indexPath];

    UpcomingRelease *upcomingRelease = [self.upReleases objectForKey:self.releaseBuckets[indexPath.section]][indexPath.row];

    cell.release_name.text = upcomingRelease.release_name;

    return cell;
}

这整个代码已测试及工程。

编辑要包含已排序的数组的键