iOS获取当天0点时间

+ (NSDate *)zeroOfDate
{
    NSCalendar *calendar = [NSCalendar currentCalendar];
    NSDateComponents *components = [calendar components:NSUIntegerMax fromDate:[NSDate date]];
    components.hour = 0;
    components.minute = 0;
    components.second = 0;
    
    // components.nanosecond = 0 not available in iOS
    NSTimeInterval ts = (double)(int)[[calendar dateFromComponents:components] timeIntervalSince1970];
    NSDate * date = [NSDate dateWithTimeIntervalSince1970:ts];
    NSTimeZone *zone = [NSTimeZone systemTimeZone];
    NSInteger interval = [zone secondsFromGMTForDate: date];
    NSDate *localeDate = [date  dateByAddingTimeInterval: interval];
    return localeDate;
}