[ios] UITableViewCell이 완전히 보이는지 확인하는 가장 좋은 방법

높이가 다른 셀이있는 UITableView가 있으며 언제 완전히 표시 되는지 여부를 알아야 합니다.

현재 나는 보이는 셀 목록의 각 셀을 반복하여보기를 스크롤 할 때마다 완전히 보이는지 확인합니다. 이것이 최선의 접근 방식입니까?

내 코드는 다음과 같습니다.

- (void)scrollViewDidScroll:(UIScrollView *)aScrollView {

    CGPoint offset = aScrollView.contentOffset;
    CGRect bounds = aScrollView.bounds;
    NSArray* cells = myTableView.visibleCells;

    for (MyCustomUITableViewCell* cell in cells) {

        if (cell.frame.origin.y > offset.y &&
            cell.frame.origin.y + cell.frame.size.height < offset.y + bounds.size.height) {

            [cell notifyCompletelyVisible];
        }
        else {

            [cell notifyNotCompletelyVisible];
        }
    }
}

편집하다:

*-(NSArray ) visibleCells 는 완전히 표시되고 부분적으로 표시되는 표시 셀을 반환합니다.

편집 2 :

이것은 lnafziger 와 Vadim Yelagin의 솔루션을 결합한 후 수정 된 코드입니다 .

- (void)scrollViewDidScroll:(UIScrollView *)aScrollView {
    NSArray* cells = myTableView.visibleCells;
    NSArray* indexPaths = myTableView.indexPathsForVisibleRows;

    NSUInteger cellCount = [cells count];

    if (cellCount == 0) return;

    // Check the visibility of the first cell
    [self checkVisibilityOfCell:[cells objectAtIndex:0] forIndexPath:[indexPaths objectAtIndex:0]];

    if (cellCount == 1) return;

    // Check the visibility of the last cell
    [self checkVisibilityOfCell:[cells lastObject] forIndexPath:[indexPaths lastObject]];

    if (cellCount == 2) return;

    // All of the rest of the cells are visible: Loop through the 2nd through n-1 cells
    for (NSUInteger i = 1; i < cellCount - 1; i++)
        [[cells objectAtIndex:i] notifyCellVisibleWithIsCompletelyVisible:YES];
}

- (void)checkVisibilityOfCell:(MultiQuestionTableViewCell *)cell forIndexPath:(NSIndexPath *)indexPath {
    CGRect cellRect = [myTableView rectForRowAtIndexPath:indexPath];
    cellRect = [myTableView convertRect:cellRect toView:myTableView.superview];
    BOOL completelyVisible = CGRectContainsRect(myTableView.frame, cellRect);

    [cell notifyCellVisibleWithIsCompletelyVisible:completelyVisible];
}

답변

let cellRect = tableView.rectForRowAtIndexPath(indexPath)
let completelyVisible = tableView.bounds.contains(cellRect)

CGRect cellRect = [tableView rectForRowAtIndexPath:indexPath];
BOOL completelyVisible = CGRectContainsRect(tableView.bounds, cellRect);

- (void)checkVisibilityOfCell:(MyCustomUITableViewCell *)cell inScrollView:(UIScrollView *)aScrollView {
    CGRect cellRect = [aScrollView convertRect:cell.frame toView:aScrollView.superview];

    if (CGRectContainsRect(aScrollView.frame, cellRect))
        [cell notifyCompletelyVisible];
    else
        [cell notifyNotCompletelyVisible];
}

- (void)scrollViewDidScroll:(UIScrollView *)aScrollView {
    NSArray* cells = myTableView.visibleCells;

    NSUInteger cellCount = [cells count];
    if (cellCount == 0)
        return;

    // Check the visibility of the first cell
    [self checkVisibilityOfCell:[cells firstObject] inScrollView:aScrollView];
    if (cellCount == 1)
        return;

    // Check the visibility of the last cell
    [self checkVisibilityOfCell:[cells lastObject] inScrollView:aScrollView];
    if (cellCount == 2)
        return;

    // All of the rest of the cells are visible: Loop through the 2nd through n-1 cells
    for (NSUInteger i = 1; i < cellCount - 1; i++)
        [[cells objectAtIndex:i] notifyCompletelyVisible];
}

-(void)scrollViewDidScroll:(UIScrollView *)sender
{
    [self checkWhichVideoToEnable];
}

-(void)checkWhichVideoToEnable
{
    for(UITableViewCell *cell in [tblMessages visibleCells])
    {
        if([cell isKindOfClass:[VideoMessageCell class]])
        {
            NSIndexPath *indexPath = [tblMessages indexPathForCell:cell];
            CGRect cellRect = [tblMessages rectForRowAtIndexPath:indexPath];
            UIView *superview = tblMessages.superview;

            CGRect convertedRect=[tblMessages convertRect:cellRect toView:superview];
            CGRect intersect = CGRectIntersection(tblMessages.frame, convertedRect);
            float visibleHeight = CGRectGetHeight(intersect);

            if(visibleHeight>VIDEO_CELL_SIZE*0.6) // only if 60% of the cell is visible
            {
                // unmute the video if we can see at least half of the cell
                [((VideoMessageCell*)cell) muteVideo:!btnMuteVideos.selected];
            }
            else
            {
                // mute the other video cells that are not visible
                [((VideoMessageCell*)cell) muteVideo:YES];
            }
        }
    }
}

extension UITableView {

    public var boundsWithoutInset: CGRect {
        var boundsWithoutInset = bounds
        boundsWithoutInset.origin.y += contentInset.top
        boundsWithoutInset.size.height -= contentInset.top + contentInset.bottom
        return boundsWithoutInset
    }

    public func isRowCompletelyVisible(at indexPath: IndexPath) -> Bool {
        let rect = rectForRow(at: indexPath)
        return boundsWithoutInset.contains(rect)
    }
}

- (BOOL)checkVisibilityOfCell{
    if (tableView.contentSize.height <= tableView.frame.size.height) {
        return YES;
    } else{
        return NO;
    }
}

UICollectionViewCell *cell = [self.collectionView cellForItemAtIndexPath:indexPath];
CGRect frame = cell.frame;
if (CGRectContainsRect(CGRectOffset(self.collectionView.frame, self.collectionView.contentOffset.x, self.collectionView.contentOffset.y), frame))
{
    // is on screen
}