如何在“viewForHeaderInSection”中为UILabel视图设置自动布局约束

Question

如何在“viewForHeaderInSection”中为UILabel视图设置自动布局约束

iosswiftuitableviewautolayoutconstraints

9

 func tableView(tableView:UITableView, viewForHeaderInSection section:Int) -> UIView?{
        let newlabel = UILabel()
        //206-250

        newlabel.backgroundColor = UIColor(red: (135/255), green:(206/255), blue: (250/255), alpha: 1)
        newlabel.textColor = UIColor(white: 1, alpha: 1)
        newlabel.textAlignment = .Right
        newlabel.font = newlabel.font.fontWithSize(18)
        newlabel.adjustsFontSizeToFitWidth = true
        let horizontalcontraint = NSLayoutConstraint(item: newlabel, attribute: .Trailing, relatedBy: .Equal, toItem: view, attribute: .Trailing, multiplier: 1, constant: -20)
        NSLayoutConstraint.activateConstraints([horizontalcontraint])

        newlabel.constraints
        newlabel.text = keys[section]+" - "
        return newlabel
    }

我不确定如何在约束的toItem:部分引用节标题。任何建议都将不胜感激。UILabel紧贴在标头的右侧，看起来很糟糕。我需要一点间距。

- BostonMacOSX

1

将-20的值更改为20并尝试，但我认为这不会起作用，因为您只是使用标签。按照我的建议，您应该使用UIView，然后从标签向视图添加各种约束，并将UIView作为标题返回。 - Mahesh Agrawal

1个回答

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- Mahesh Agrawal · Accepted Answer

我修改了你的代码，这是修改后的版本，请试一试。

func tableView(tableView:UITableView, viewForHeaderInSection section:Int) -> UIView?{
    let headerView = UIView()
    headerView.backgroundColor = UIColor.clearColor()
    let newlabel = UILabel()
    //206-250

    newlabel.backgroundColor = UIColor(red: (135/255), green:(206/255), blue: (250/255), alpha: 1)
    newlabel.textColor = UIColor(white: 1, alpha: 1)
    newlabel.textAlignment = .Right
    newlabel.font = newlabel.font.fontWithSize(18)
    newlabel.adjustsFontSizeToFitWidth = true

    newlabel.constraints
    newlabel.text = keys[section]+" - "

    headerView.addSubview(newlabel)
    newlabel.translatesAutoresizingMaskIntoConstraints = false
    headerView.addConstraint(NSLayoutConstraint(item: newlabel, attribute: NSLayoutAttribute.Leading, relatedBy: NSLayoutRelation.Equal, toItem: headerView, attribute: NSLayoutAttribute.Leading, multiplier: 1.0, constant: 0))
    headerView.addConstraint(NSLayoutConstraint(item: newlabel, attribute: NSLayoutAttribute.Trailing, relatedBy: NSLayoutRelation.Equal, toItem: headerView, attribute: NSLayoutAttribute.Trailing, multiplier: 1.0, constant: 20.0))
    headerView.addConstraint(NSLayoutConstraint(item: newlabel, attribute: NSLayoutAttribute.Top, relatedBy: NSLayoutRelation.Equal, toItem: headerView, attribute: NSLayoutAttribute.Top, multiplier: 1.0, constant: 0))
    headerView.addConstraint(NSLayoutConstraint(item: newlabel, attribute: NSLayoutAttribute.Bottom, relatedBy: NSLayoutRelation.Equal, toItem: headerView, attribute: NSLayoutAttribute.Bottom, multiplier: 1.0, constant: 0))

    return headerView
}