PHFetchOptions 谓词与 NSDate 比较

Question

你好，我一直在使用 Photos.framework，但现在我在文档中遇到 PHFetchOptions class 的谓词比较问题，我看到我们可以使用 startDate 来使用在谓词中。所以我的代码是这样

@interface ViewController ()
{
    NSMutableArray * moments;
}



@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    moments = [NSMutableArray array];

    if([PHPhotoLibrary authorizationStatus] == PHAuthorizationStatusNotDetermined)
    {
        [PHPhotoLibrary requestAuthorization:^(PHAuthorizationStatus status) {
            [self loadCollections];
        }];
    }else
    {
        [self loadCollections];
    }

}

- (void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:animated];
    [self loadCollections];
}


- (NSDate*)dateAddingDays:(NSInteger)days ToDate:(NSDate*)argDate
{
    NSCalendar * gregorian = [NSCalendar currentCalendar];

    NSDateFormatter * formatter = [[NSDateFormatter alloc]init];
    [formatter setDateFormat:@"dd.MM.yyyy"];
    NSString * dateString = [formatter stringFromDate:argDate];
    NSDate * toWorkDate = [formatter dateFromString:dateString];

    NSDateComponents *comps = [[NSDateComponents alloc] init];
    [comps setDay:days];
    NSDate *date = [gregorian dateByAddingComponents:comps toDate:toWorkDate  options:0];
    NSLog(@"%@",[formatter stringFromDate:date]);
    return date;
}

- (void)loadCollections
{
    PHFetchOptions * options = [[PHFetchOptions alloc]init];

    options.predicate = [NSComparisonPredicate predicateWithFormat:@"startDate > CAST(%d,\"NSDate\")",[self dateAddingDays2:-1 ToDate:[NSDate date]].timeIntervalSince1970];
    PHFetchResult * result = [PHAssetCollection fetchMomentsWithOptions:options];

    if(result != nil)
    {
        NSLog(@"%i",result.count);
        for (int i = 0; i < result.count; i++) {
            NSLog(@"%@",[result objectAtIndex:i]);
            [moments addObject:[result objectAtIndex:i]];
        }
    }

}

所以我的问题是这个，我需要获取一天前的照片，我可以完成这项工作！！任何帮助将不胜感激。

Answer 1

这就是答案，基本上我换成了

- (NSDate*)dateAddingDays:(NSInteger)days ToDate:(NSDate*)argDate
{
    NSCalendar * gregorian = [NSCalendar currentCalendar];

    NSDateFormatter * formatter = [[NSDateFormatter alloc]init];
    [formatter setDateFormat:@"dd.MM.yyyy"];
    NSString * dateString = [formatter stringFromDate:argDate];
    NSDate * toWorkDate = [formatter dateFromString:dateString];

    NSDateComponents *comps = [[NSDateComponents alloc] init];
    [comps setDay:days];
    NSDate *date = [gregorian dateByAddingComponents:comps toDate:toWorkDate  options:0];
    NSLog(@"%@",[formatter stringFromDate:date]);
    return date;
}

来自

- (NSDate*)yesterday
{
    NSCalendar * gregorian = [NSCalendar currentCalendar];
    return [gregorian startOfDayForDate:[gregorian dateByAddingUnit:NSCalendarUnitDay value:-1 toDate:[NSDate date] options:NSCalendarWrapComponents]];
}

并替换这个

options.predicate = [NSComparisonPredicate predicateWithFormat:@"startDate > CAST(%d,\"NSDate\")",[self dateAddingDays2:-1 ToDate:[NSDate date]].timeIntervalSince1970];

由此

options.predicate = [NSComparisonPredicate predicateWithFormat:@"(startDate > %@)",[self yesterday]];

现在正在工作！！！感谢@Larme

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