Update Constraints of Cell Subview

Question

I have a custom cell & I am trying to update constraints of subview as below:

CustomeCell.m

-(void)layoutSubviews
{
    [super layoutSubviews];

    _con_view_width.constant = _lbl_property.frame.size.width;
    if(!_btn_imageCount.isHidden)
    _con_view_width.constant = _lbl_property.frame.size.width + _btn_imageCount.frame.size.width;

    NSLog(@"%@",NSStringFromCGRect(_view_lbl_btn.frame));

    [_view_lbl_btn updateConstraintsIfNeeded];
    NSLog(@"%@",NSStringFromCGRect(_view_lbl_btn.frame));

}

Problem The constraint are working only after reload rows when scrolling

Try to do that with animation block. Look here: http://stackoverflow.com/a/32134857/3718570 — Ptah, Aug 22 '15 at 23:14

Mahesh Agrawal · Answer 1 · 2015-07-06T07:00:05.657

9

Instead of updateConstraintsIfNeeded try layoutIfNeeded. i think its will work and your code should look like this.

-(void)layoutSubviews
{
    [super layoutSubviews];

    _con_view_width.constant = _lbl_property.frame.size.width;
    if(!_btn_imageCount.isHidden)
    _con_view_width.constant = _lbl_property.frame.size.width + _btn_imageCount.frame.size.width;

    NSLog(@"%@",NSStringFromCGRect(_view_lbl_btn.frame));

    [_view_lbl_btn layoutIfNeeded];
    NSLog(@"%@",NSStringFromCGRect(_view_lbl_btn.frame));

}

EDIT: If you are doing this inside custom cell class then you need to add one more line to cell for row at index path.

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"Cell" forIndexPath:indexPath];
    //[cell layoutIfNeeded];
    [cell layoutSubviews];
    return cell;
}

edited Jul 06 '15 at 07:00

answered Jul 06 '15 at 06:48

Mahesh Agrawal

3,348
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are you doing this inside custom class of table view cell? – Mahesh Agrawal Jul 06 '15 at 06:53
then inside cell for row at index path..just after initializing cell write like this. [cell layoutIfNeeded]; – Mahesh Agrawal Jul 06 '15 at 06:56
I will get right frame now but UI is not updated on screen. – user2526811 Jul 06 '15 at 06:59
then try [cell layoutSubViews];. I was also having this type of problem. One of those two option must work. – Mahesh Agrawal Jul 06 '15 at 07:01
try [cell layoutSubViews]; then I am not getting right frame – user2526811 Jul 06 '15 at 07:06
Let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/82451/discussion-between-mahesh-agrawal-and-user2526811). – Mahesh Agrawal Jul 06 '15 at 07:08
1

@MaheshAgrawal did you ever find a solution to this problem? I'm experiencing the same issue. – inga May 06 '16 at 15:09
for me, it was solved by doing layoutIfNeeded and i was getting correct values. – Mahesh Agrawal May 14 '16 at 02:59
Thanks, layoutIfNeeded worked perfectly for me, and in Swift 5 still working, in my case I had to use that because I update a Collection view cell size after loading from xib file. – Pedro Ortiz Jan 18 '20 at 16:17

score 2 · Answer 2 · answered Jan 16 '17 at 20:38

try to update the constraints in the method used to return cell to tableview in data source delegation instead of the method layoutSubviews in cell.

And call cell.contentView.layoutIfNeeded() before updating the constraints which will set the cell to default width and height (320, 44 something based on the devices), in case that you can get the width. After cell returned by the delegation to tableview. The cell size will be updated by the tableview (framework does for your), if you set some constraints which either directly or relatively change the size.

Update Constraints of Cell Subview

2 Answers2

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