My cell's resize after scrolling upwards?

问题:

I have a problem with my TableViewCell's layout. Currently when I scroll upwards in my tableView I have found a strange and annoying bug. When I decide to release the "scroll", meaning I am dropping "the scroll" so the "View" will return to its normal position showing all of the TableView's content, some of my cell's can for some reason re-size themselves on the width. I have no clue why this occur or what the problem might be.

All my cell's are customized to fitSize depending on the height of the label (commentLabel) in my forum. I assume the problem may be in how I am trying to customize my cell's content. I will post my relevant code and also post to pictures below.

Before starting to drag the scroll upwards: http://tinypic.com/view.php?pic=2rfsum9&s=6

After release/droped the scroll again to its normal position. Now one of the cell's changed: http://tinypic.com/view.php?pic=swxnqv&s=6

Code:

- (UITableViewCell *)tableView:(UITableView *)pTableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"ForumthreadCell";
    UITableViewCell *cell = [pTableView dequeueReusableCellWithIdentifier:CellIdentifier];

    if (cell == nil)
    {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
    }

    Feedback *item = [self.items objectAtIndex:indexPath.row];

    UILabel *aliasLabel = (UILabel *)[cell viewWithTag:1];
    UILabel *commentLabel = (UILabel *)[cell viewWithTag:2];
    UILabel *dateLabel = (UILabel *)[cell viewWithTag:3];

    [aliasLabel setText:item.alias];
    [commentLabel setText:item.comment];
    [dateLabel setText:[self.dateFormatter stringFromDate:[NSDate dateWithTimeIntervalSince1970:(double)item.time]]];

    commentLabel.numberOfLines = 0;
    [commentLabel sizeToFit];
    [aliasLabel sizeToFit];
    [dateLabel sizeToFit];

    return cell;
}

-(CGFloat)getLabelHeightForText:(NSString *)text andWidth:(CGFloat)labelWidth
{

    CGSize maximumSize = CGSizeMake(labelWidth, 10000);

    //provide appropriate font and font size
    CGSize labelHeighSize = [text sizeWithFont: [UIFont fontWithName:@"Trebuchet MS" size:12.0f]
                         constrainedToSize:maximumSize
                             lineBreakMode:UILineBreakModeTailTruncation];
    return labelHeighSize.height;
 }

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
    Feedback *item = [self.items objectAtIndex:indexPath.row];

    CGFloat commentTextHeight = [self getLabelHeightForText:item.comment andWidth:162];
    return commentTextHeight + 39;
}

EDIT

NSLog(@"bounds.origin.x: %f", commentLabel.bounds.origin.x);
NSLog(@"bounds.origin.y: %f", commentLabel.bounds.origin.y);
NSLog(@"bounds.size.width: %f", commentLabel.bounds.size.width);
NSLog(@"bounds.size.height: %f", commentLabel.bounds.size.height);

NSLog(@"frame.origin.x: %f", commentLabel.frame.origin.x);
NSLog(@"frame.origin.y: %f", commentLabel.frame.origin.y);
NSLog(@"frame.size.width: %f", commentLabel.frame.size.width);
NSLog(@"frame.size.height: %f", commentLabel.frame.size.height);

resulted in this output for 1 cell (1 commentLabel output)

purgeIdleCellConnections: found one to purge conn = 0x1dd654f0
 bounds.origin.x: 0.000000
 bounds.origin.y: 0.000000
 bounds.size.width: 162.000000
 bounds.size.height: 10039.000000
 frame.origin.x: 12.000000
 frame.origin.y: 28.000000
 frame.size.width: 162.000000
 frame.size.height: 10039.000000

回答1:

When you reuse the cells, you should set the frames of all of the labels. The reason of that is -sizeToFit will change the frames of the labels, so when you reuse the cells, the frames of labels have already altered.

EDIT

You may do this in this way:

static const CGFloat kLabelWidth = 162;
static const CGFloat kOffset = 39;

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    static NSString *identifier = @"identifier";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:identifier];
    if (!cell) {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:identifier];
    }

    UILabel *commentLabel = (UILabel *)[cell.contentView viewWithTag:2];
    CGRect frame = commentLabel.frame;
    frame.size.width = kLabelWidth;
    frame.size.height = 10000;
    commentLabel.frame = frame;
    commentLabel.text = @"your text";
    [commentLabel sizeToFit];

    frame = commentLabel.frame;
    frame.size.height += kOffset;
    commentLabel.frame = frame;

    return cell;
}


- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath  {
    CGFloat commentTextHeight = [self getLabelHeightForText:@"your text" andWidth:kLabelWidth];
    return commentTextHeight + kOffset;
}