更新单元格子视图的约束 [英] Update Constraints of Cell Subview

问题描述

我有一个自定义单元格&我正在尝试更新子视图的约束，如下所示:

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));

}

问题 约束仅在滚动后重新加载行后有效

Problem The constraint are working only after reload rows when scrolling

推荐答案

而不是updateConstraintsIfNeeded，请尝试layoutIfNeeded.我认为它将起作用，并且您的代码应如下所示.

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));

}

如果要在自定义单元格类中进行此操作，则需要在单元格的索引路径处再添加一行.

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;
}

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