NSDateComponents在两个日期之间获取日期的日期属性不正确

Question

我正在使用NSDateComponents和NSCalendar获取两个日期之间的日期。

// Get dates between before and after 
NSDateComponents *betweenDateComponents = [calendar components:componentFlags 
                 fromDate:afterDate 
                  toDate:beforeDate 
                 options:0]; 

然后我有一个简单的循环，是基于组件的天属性：

for (int i = 1; i < betweenDateComponents.day; ++i) { 

这完美的作品时，我所有的一个月工作了一个星期，或者。如果按星期过滤，则日期属性日志记录为6.如果按月过滤日期属性为29，但由于某种原因，当我按年份过滤时，日期属性记录为29而不是364.

为什么当我尝试与一年的工作时，这一天的财产总是错误的？

这里是我的所有代码，直到for循环我上面包括：

// Set the date components according to the type of filter we're doing 
    NSCalendar *calendar = [NSCalendar currentCalendar]; 
    NSDateComponents *components = [NSDateComponents new]; 
    if (filterType == CommentFilterTypeWeeklyByDay) { 
     [components setDay:-6]; 
    } else if (filterType == CommentFilterTypeMonthlyByDay) { 
     [components setDay:-29]; 
    } else if (filterType == CommentFilterTypeYearlyByMonth) { 
     [components setDay:-364]; 
    } 

    NSUInteger componentFlags = NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit; 

    // Zero out before and after dates 
    NSDate *beforeDate = [NSDate date]; 
    NSDateComponents *zeroComponents = [[NSCalendar currentCalendar] components:componentFlags fromDate:beforeDate]; 
    beforeDate = [calendar dateFromComponents:zeroComponents]; 

    NSDate *afterDate = [calendar dateByAddingComponents:components toDate:beforeDate options:0]; 
    zeroComponents = [[NSCalendar currentCalendar] components:componentFlags fromDate:afterDate]; 
    afterDate = [calendar dateFromComponents:zeroComponents]; 

    NSMutableArray *dates = [NSMutableArray new]; 
    [dates addObject:afterDate]; 

    // Get dates between before and after 
    NSDateComponents *betweenDateComponents = [calendar components:componentFlags 
                  fromDate:afterDate 
                  toDate:beforeDate 
                  options:0]; 
    NSLog(@"%d", betweenDateComponents.day); 

    for (int i = 1; i < betweenDateComponents.day; ++i) { 

Answer 1

因为你的组件包括：NSYearCalendarUnit和NSMonthCalendarUnit，我怀疑你将不得不使用month和year而不是仅仅day。这些组件是累积的，不是独立的。

您随时都可以通过改变得到的天只是数（不管有多少个月或数年都是你日期间），您components：

NSCalendar *calendar = [NSCalendar currentCalendar]; 
NSDateComponents *components = [NSDateComponents new]; 

switch (filterType) { 
    case CommentFilterTypeWeeklyByDay: [components setDay:-6]; break; 
    case CommentFilterTypeMonthlyByDay: [components setDay:-29]; break; 
    case CommentFilterTypeYearlyByMonth: [components setDay:-364]; break; 
    case CommentFilterTypeCustom: [components setDay:-590]; break; 
    default: break; 
} 

NSUInteger componentFlags = NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit; 
NSDate *beforeDate = [NSDate date]; 
NSDateComponents *zeroComponents = [[NSCalendar currentCalendar] components:componentFlags fromDate:beforeDate]; 
beforeDate = [calendar dateFromComponents:zeroComponents]; 

NSDate *afterDate = [calendar dateByAddingComponents:components toDate:beforeDate options:0]; 
zeroComponents = [[NSCalendar currentCalendar] components:componentFlags fromDate:afterDate]; 
afterDate = [calendar dateFromComponents:zeroComponents]; 

NSDateComponents *betweenDateComponents = [calendar components:NSDayCalendarUnit 
                 fromDate:afterDate 
                 toDate:beforeDate 
                 options:0]; 

NSLog(@"%d", betweenDateComponents.day); 

的NSLog这里打印

6为CommentFilterTypeWeeklyByDay

29为CommentFilterTypeMonthlyByDay

364为CommentFilterTypeYearlyByMonth

590为CommentFilterTypeCustom