Question

在我的数据库中我有两列，即startDate和endDate，如果用户在UI中按下任何日期，如16July 2015那么它应该获取介于startDate和endDate之间的所有事件。

之前我写了一个用于获取凝视事件的谓词：

[NSPredicate predicateWithFormat:[NSString stringWithFormat:@"%@ >= %%@ AND %@ < %%@", @"startTime", @"endTime"], date, [date dateForNextDay]]

但如果给定日期不是事件的开始日期，则上述查询将无效。

实施例：如果我的会议日期为7/13 - 7/16且给定日期为7/14，则会议事件应该能够使用谓词获取。我的旧查询仅适用于7月13日。它应该在给定日期获取该事件 - 7 / 13,7 / 14,7 / 15,7 / 16

Answer 1

获取给定日期大于或等于或小于或等于给定日期的事件....

[NSPredicate predicateWithFormat:@"%@ >= startTime AND %@ <= endTime", date, date]

编辑... 使用简单对象对此进行测试即可确认其正常运行....

- (NSArray *)filterArray:(NSArray *)array forDate:(NSDate *)date {
    NSPredicate *p = [NSPredicate predicateWithFormat:@"%@ >= startTime AND %@ <= endTime", date, date];
    return [array filteredArrayUsingPredicate:p];
}

- (void)testPredicate {

    NSDictionary *event0 = @{ @"startTime":[self dateFromString:@"07/01/2015"], @"endTime":[self dateFromString:@"07/04/2015"] };
    NSDictionary *event1 = @{ @"startTime":[self dateFromString:@"07/10/2015"], @"endTime":[self dateFromString:@"07/14/2015"] };
    NSDictionary *event2 = @{ @"startTime":[self dateFromString:@"08/02/2015"], @"endTime":[self dateFromString:@"08/09/2015"] };

    NSArray *events = @[event0, event1, event2];

    NSDate *july9 = [self dateFromString:@"07/09/2015"];
    NSDate *july10 = [self dateFromString:@"07/10/2015"];
    NSDate *july11 = [self dateFromString:@"07/11/2015"];
    NSDate *july13 = [self dateFromString:@"07/13/2015"];
    NSDate *july14 = [self dateFromString:@"07/14/2015"];
    NSDate *july15 = [self dateFromString:@"07/15/2015"];

    NSLog(@"filtered using 9 should be empty %@", [self filterArray:events forDate:july9]);
    NSLog(@"filtered using 10 should hit %@", [self filterArray:events forDate:july10]);
    NSLog(@"filtered using 11 should hit %@", [self filterArray:events forDate:july11]);
    NSLog(@"filtered using 13 should hit %@", [self filterArray:events forDate:july13]);
    NSLog(@"filtered using 14 should hit %@", [self filterArray:events forDate:july14]);
    NSLog(@"filtered using 15 should be empty %@", [self filterArray:events forDate:july15]);
}

- (NSDate *)dateFromString:(NSString *)string {
    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setDateFormat:@"MM/dd/yyyy"];
    return [dateFormatter dateFromString:string];
}

上述情况不需要对午夜案件进行特殊处理，以便按照问题的建议（包括最后的结束时间）执行。

这将生成以下日志输出，您可以自行确认...

filtered using 9 should be empty ()
filtered using 10 should hit (
        {
        endTime = "2015-07-14 07:00:00 +0000";
        startTime = "2015-07-10 07:00:00 +0000";
    }
)
filtered using 11 should hit (
        {
        endTime = "2015-07-14 07:00:00 +0000";
        startTime = "2015-07-10 07:00:00 +0000";
    }
)
filtered using 13 should hit (
        {
        endTime = "2015-07-14 07:00:00 +0000";
        startTime = "2015-07-10 07:00:00 +0000";
    }
)
filtered using 14 should hit (
        {
        endTime = "2015-07-14 07:00:00 +0000";
        startTime = "2015-07-10 07:00:00 +0000";
    }
)
filtered using 15 should be empty ()

Answer 2

我不明白为什么你有两个日期：date和dateForNextDay。

我认为你应该试试这个： [NSPredicate predicateWithFormat：@＆＃34; startTime＆gt; =％@＆amp;＆amp; ％@＆lt; endTime＆＃34;，date，[date dateForNextDay]];

或者只是转换你的最后％@ 和 %% @ ，就像这样=＆gt; @＆＃34;％@＆gt; = %% @ AND %% @＆lt; ％@＆＃34;

编辑：顺便说一句，正如@danh所说，您可能只想使用日期，日期。

Edit2：好的，我的回答太快了，所有条件都是假的，而且danh再次正确;） @＆＃34; startTime＆lt; =％@＆amp;＆amp; ％@＆lt; = endTime＆＃34;

NSPredicate为多日全天活动

2 个答案: