如何以編程方式讓 UITableView 滾動到特定部分

Question

在我的日歷應用程序中，我希望我的 UITableView 根據點擊的日期滾動到特定部分。 當前的實現如下：

- (void)calendarDidDateSelected:(JTCalendar *)calendar date:(NSDate *)date
{
    // Format NSDate so it can be compared to date selected
    static NSDateFormatter *dateFormatter = nil;
    if(!dateFormatter){
        dateFormatter = [NSDateFormatter new];
        dateFormatter.dateFormat = @"yyyy-MM-dd"; // Read the documentation for dateFormat
    }

    // Set formatted dates
    NSDate *juneSixteenth = [dateFormatter dateFromString:@"2015-06-16"];
    NSDate *juneSeventeenth = [dateFormatter dateFromString:@"2015-06-17"];

    // Set date selected, so agendaTable knows which event to show
    if([juneSixteenth compare:date] == NSOrderedSame){
        NSLog(@"You picked June 16th");
        self.datePicked = [NSNumber numberWithInt:16];
    }
    else if([juneSeventeenth compare:date] == NSOrderedSame){
        NSLog(@"You picked June 17th");
        self.datePicked = [NSNumber numberWithInt:17];
    }
    else {
        _datePicked = nil;
        NSLog(@"Date: %@", date);
    }
    [self.agendaTable reloadData];
}

我發現了一個類似的問題，說要這樣做：

       if([juneSixteenth compare:date] == NSOrderedSame){
            NSLog(@"You picked June 16th");
            self.datePicked = [NSNumber numberWithInt:16];

            //"row" below is row selected in the picker view
            NSIndexPath *ip = [NSIndexPath indexPathForRow:0 inSection:row];

            [self.agendaTable scrollToRowAtIndexPath:ip
                          atScrollPosition:UITableViewScrollPositionNone
                                  animated:YES];
        }

這給出了一個錯誤，指出row是一個未聲明的標識符，我希望它使用節索引而不是行。 我將如何實現這一點？

Answer 1

嘗試這個

[NSIndexPath indexPathForRow:NSNotFound inSection:section]

Answer 2

斯威夫特 3.0

DispatchQueue.main.async {
   let indexPath = IndexPath(item: 'item', section: 'section')
   self.tableView.scrollToRow(at: indexPath, at: .top, animated: true)
}

Answer 3

@black-sheep 答案的 Swift 版本：

let sectionIndexPath = IndexPath(row: NSNotFound, section: section)

Answer 4

當您的部分沒有單元格時，例如它只有頁眉或頁腳，您可以使用以下選項之一：

let sectionRect = yourTable.rect(forSection: sectionNumber)
yourTable.setContentOffset(CGPoint(x: sectionRect.origin.x, y: sectionRect.origin.y), animated: true)

或者

let sectionRect = yourTable.rect(forSection: sectionNumber)
yourTable.scrollRectToVisible(sectionRect, animated: false)

Answer 5

行必須是 int 值，該變量定義在 .h 中，並在 .m 類中的任何地方使用此變量，您要在特定位置滾動。

您可以在特定部分滾動 UITableView，也可以使用以下代碼滾動到部分的特定索引單元格：

NSIndexPath *indexPath = [NSIndexPath indexPathForRow:0 inSection:0];
[MytblView scrollToRowAtIndexPath:indexPath 
                     atScrollPosition:UITableViewScrollPositionTop 
                             animated:YES];

Answer 6

您必須找到/計算要滾動的section和row

NSInteger row = ??;//you have to find/calculate which row you want to show
NSInteger section = ??;//you have to find/calculate which row of the sections you want to show
NSIndexPath *ip = [NSIndexPath indexPathForRow:row inSection:section];

[self.agendaTable scrollToRowAtIndexPath:ip
                        atScrollPosition:UITableViewScrollPositionNone
                                animated:YES];