Ios UILabel赢得'；UIView中的t中心

我正在尝试创建一个自定义的

ui视图

，它可以用作进度条或类似的（

@IBDesignable

，带有

IBInspectable

s）。在这个视图中，我想要一个居中的（主要是X轴，但现在也是Y轴）

UILabel

private func addLabel()
{
    let label = UILabel(frame: CGRectMake(0, 0, self.frame.width / 4, self.frame.height / 4))
    label.center = self.center
    label.textAlignment = .Center
    label.text = "5"
    //Color just to see the whole label
    label.backgroundColor = UIColor.redColor().colorWithAlphaComponent(0.5)
    self.addSubview(label)
}

在Interfacebuilder中，标签正好居中：

但是，在我的设备（iPhone 5S）上运行时，标签稍微向右对齐（下图）。我尝试过不同的方法（比如制作标签框

self.frame

），但仍然没有正确居中。我错过了什么

---

问题是

label.center=self.center

，因为标签的中心和superview的中心位于不同的坐标系中，因此它们可能不相同。改用

label.center = CGPoint(x: self.view.frame.bounds.size.width / 2.0, y:self.view.frame.bounds.size.height / 2.0)

试试这个：

self.label.center = view.center

---

以编程方式添加UILabel，并从中修改UILabel框架

let label = UILabel(frame: CGRectMake(0, 0, self.frame.width / 4, self.frame.height / 4))

到

其他

---

实施自动布局

可能的解决方案是：-

@IBOutlet customView : UIView! 
//Let customView be the outlet of your custom view

func addLabel () {
    let CenterY = customView.center.y
    let CenterX = customView.center.x
    let heightOfCustom = customView.frame.size.height
    let widthOfCustom = customView.frame.size.width
    // If you want a label with height and width 1/4th of the width of the custom view
    let label = UILabel(frame : CGRectMake(CenterX - widthOfCustom/8, CenterY - heightOfCustom/8, widthOfCustom/4, heightOfCustom/4))
    label.text = "5"
    label.textAlignment = .Center
    label.backgroundColor = UIColor.redColor().colorWithAlphaComponent(0.5)
    self.addSubview(label)
}

---

通过Nib/故事板文件中的自动布局对齐UILabel Center。感谢您的解释和解决方案！

let label = UILabel(frame: CGRectMake(self.frame.width/2 - (self.frame.height/4)/2, 0, self.frame.width / 4, self.frame.height / 4))

@IBOutlet customView : UIView! 
//Let customView be the outlet of your custom view

func addLabel () {
    let CenterY = customView.center.y
    let CenterX = customView.center.x
    let heightOfCustom = customView.frame.size.height
    let widthOfCustom = customView.frame.size.width
    // If you want a label with height and width 1/4th of the width of the custom view
    let label = UILabel(frame : CGRectMake(CenterX - widthOfCustom/8, CenterY - heightOfCustom/8, widthOfCustom/4, heightOfCustom/4))
    label.text = "5"
    label.textAlignment = .Center
    label.backgroundColor = UIColor.redColor().colorWithAlphaComponent(0.5)
    self.addSubview(label)
}