Question

我有一个tableview，其中包含日程约会。每天都是单独的section。你可以在这里看到我的意思

enter image description here

现在我希望tableview滚动到今天的section，或者如果今天没有section滚动到最近的那个。

我知道我应该使用以下代码：

 [tableView scrollToRowAtIndexPath:scrollIndexPath atScrollPosition:UITableViewScrollPositionBottom animated:YES];

现在我有一个NSMutableDictionary，其中包含我已排序的约会/日。您可以看到以下功能：

-(NSDictionary *)sortKalendar:(NSMutableArray *)appointments{
    NSMutableDictionary *buffer = [[NSMutableDictionary alloc] init];

    NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
    [formatter setDateFormat:@"dd-MM-yyyy"];

    for (int i = 0; i < appointments.count; i++) {
        Appointment *object = [appointments objectAtIndex:i];
        NSString *date = [formatter stringFromDate:object.app_start];
        if(!(date == NULL) ){
            NSLog(@"date is %@",date);
            if ([buffer objectForKey:date]) {
                [(NSMutableArray *)[buffer objectForKey:date] addObject:object];
            } else {
                NSMutableArray *mutableArray = [[NSMutableArray alloc] initWithObjects:object, nil];
                [buffer setObject:mutableArray forKey:date];
            }
        }


    }
    NSDictionary *result = [NSDictionary dictionaryWithDictionary:buffer];

    return result;
}

现在我的问题是，如何才能找到正确的NSIndexpath？

提前致谢！

修改

目前我正在使用以下内容。但事情仍然不对。

NSArray *keys = [dictAppointments allKeys];

NSLog(@"KEYS ARE %@",keys)  ;
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setDateFormat:@"dd-MM-yyyy"];

NSArray *sortedArray = [keys sortedArrayUsingComparator:^(id obj1, id obj2) {
    NSDate *date1 = [formatter dateFromString:obj1];
    NSDate *date2 = [formatter dateFromString:obj2];

    NSNumber *interval1 = [NSNumber numberWithDouble:[date1 timeIntervalSinceNow]];
    NSNumber *interval2 = [NSNumber numberWithDouble:[date2 timeIntervalSinceNow]];
    return (NSComparisonResult)[interval1 compare:interval2];
}];
NSLog(@"Sorted Array %@",sortedArray);
NSString *closestDateString = [sortedArray objectAtIndex:0];
NSLog(@"Closest date string is %@",closestDateString);
int section = [keys indexOfObject:closestDateString];
NSIndexPath *scrollIndexPath = [NSIndexPath indexPathForRow:0 inSection:section];
[tableView scrollToRowAtIndexPath:scrollIndexPath atScrollPosition:UITableViewScrollPositionBottom animated:YES];

这给了我以下日志：

2014-01-07 13:28:42.420 Adsolut[9579:60b] KEYS ARE (
    "03-12-2013",
    "20-12-2013",
    "17-12-2013",
    "05-01-2014",
    "21-12-2013",
    "31-12-2013",
    "04-01-2014",
    "06-01-2014",
    "16-01-2014",
    "29-12-2013",
    "03-01-2014",
    "11-01-2014",
    "18-12-2013",
    "31-01-2014"
)
2014-01-07 13:28:42.437 Adsolut[9579:60b] Sorted Array (
    "03-12-2013",
    "17-12-2013",
    "18-12-2013",
    "20-12-2013",
    "21-12-2013",
    "29-12-2013",
    "31-12-2013",
    "03-01-2014",
    "04-01-2014",
    "05-01-2014",
    "06-01-2014",
    "11-01-2014",
    "16-01-2014",
    "31-01-2014"
)

Answer 1

您可以使用约会日期和当前日期之间的时间间隔对数组进行排序，

NSArray *keys = [yourDictionary allKeys];

NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setDateFormat:@"dd-MM-yyyy"];

NSArray *sortedArray = [keys sortedArrayUsingComparator:^(id obj1, id obj2) {
    NSDate *date1 = [formatter dateFromString:obj1];
    NSDate *date2 = [formatter dateFromString:obj2];

    NSNumber *interval1 = [NSNumber numberWithDouble:abs([date1 timeIntervalSinceNow])];
    NSNumber *interval2 = [NSNumber numberWithDouble:abs([date2 timeIntervalSinceNow])];
    return (NSComparisonResult)[interval1 compare:interval2];
}];

最近的日期，

NSString *closestDateString = [sortedArray objectAtIndex:0];

从此，

int section = [keys indexOfObject:closestDateString];
NSIndexPath *scrollIndexPath = [NSIndexPath indexPathForRow:0 inSection:section];

Answer 2

你有一个排序日期数组，不是吗？我们把它说成dateArray。

立即获取日期对象：NSDate * today = [NSDate date];

搜索dateArray到最近的日期，获取最近日期的索引。

NSDate * today = [NSDate date] ;
__block NSUInteger section = NSNotFound ;
__block NSTimeInterval timeInterval = NSTimeIntervalSince1970 ;
[dateArray enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
    NSDate * date = obj ;
    NSTimeInterval ti = [today timeIntervalSinceDate:date] ;
    if (ti < 0)
        ti = -ti ;
    if (ti <= timeInterval) {
        section = idx ;
        timeInterval = ti ;
    } else {
        *stop = YES ;
    }
}] ;

你现在知道部分索引，假设它是sectionIndex，该部分的第一行索引是0。

因此NSIndexPath为[NSIndexPath indexPathForRow:0 inSection:sectionIndex]

Answer 3

获取日期列表（从您的词典或已有的词典）。解决。循环遍历它（indexOfObjectPassingTest:）以查找今天的日期>=（或使用谓词进行过滤，然后从结果中获取第一项并获取索引）。

UITableView滚动到最接近今天日期的部分

3 个答案: