Question

我想在我的UITableCellView中居中使用UIButton。我已经在tableView cellForRowAt函数中添加了必要的代码，但是我收到了错误：

视图层次结构不是为约束准备的：当添加到视图时，约束的项必须是该视图的后代（或视图本身）。如果在组装视图层次结构之前需要解析约束，则会崩溃。打断 - [UIView（UIConstraintBasedLayout）_viewHierarchyUnpreparedForConstraint：]进行调试。

我的代码如下：

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {

            cell = UITableViewCell(
                style: .default, reuseIdentifier: Id.settingButtonCellIdentifier)
            cell!.backgroundColor = UIColor.clear
            cell!.preservesSuperviewLayoutMargins = false
            cell!.separatorInset = UIEdgeInsets.zero

            let button : UIButton = UIButton(type: UIButtonType.custom) as UIButton
            button.backgroundColor = UIColor.red
            button.setTitle("Click Me !", for: UIControlState.normal)

            cell!.addSubview(button)

            button.translatesAutoresizingMaskIntoConstraints = false
            button.addConstraint(NSLayoutConstraint(item: button, attribute: .leading, relatedBy: .equal, toItem: cell!, attribute: .leading, multiplier: 1, constant: 10))
            button.addConstraint(NSLayoutConstraint(item: button, attribute: .trailing, relatedBy: .equal, toItem: cell!, attribute: .trailing, multiplier: 1, constant: 10))
            button.addConstraint(NSLayoutConstraint(item: button, attribute: .top, relatedBy: .equal, toItem: cell!, attribute: .top, multiplier: 1, constant: 10))
            button.addConstraint(NSLayoutConstraint(item: button, attribute: .bottom, relatedBy: .equal, toItem: cell!, attribute: .bottom, multiplier: 1, constant: 10))
        }

        return cell!
    }

任何帮助将不胜感激！

Answer 1

试试这个

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {

        cell = UITableViewCell(
            style: .default, reuseIdentifier: Id.settingButtonCellIdentifier)
        cell!.backgroundColor = UIColor.clear
        cell!.preservesSuperviewLayoutMargins = false
        cell!.separatorInset = UIEdgeInsets.zero

        let button : UIButton = UIButton(type: UIButtonType.custom) as UIButton
        button.backgroundColor = UIColor.red
        button.setTitle("Click Me !", for: UIControlState.normal)

        button.translatesAutoresizingMaskIntoConstraints = false


        cell!.contentView.addSubview(button)

        cell.contentView.addConstraint(NSLayoutConstraint(item: button, attribute: .leading, relatedBy: .equal, toItem: cell.contentView, attribute: .leading, multiplier: 1, constant: 10))
        cell.contentView.addConstraint(NSLayoutConstraint(item: button, attribute: .trailing, relatedBy: .equal, toItem: cell.contentView, attribute: .trailing, multiplier: 1, constant: 10))
        cell.contentView.addConstraint(NSLayoutConstraint(item: button, attribute: .top, relatedBy: .equal, toItem: cell.contentView, attribute: .top, multiplier: 1, constant: 10))
        cell.contentView.addConstraint(NSLayoutConstraint(item: button, attribute: .bottom, relatedBy: .equal, toItem: cell.contentView, attribute: .bottom, multiplier: 1, constant: 10))
    }

    return cell!
}

为UITableCellView中的视图添加NSLayoutConstraint

1 个答案: