如何以编程方式将笔尖添加到UIStackView

Question

我正在尝试从笔尖添加任意数量的视图到UIStackView中。 问题是，如果只包含一个视图，则该视图会增长为填充整个堆栈视图，而不是保持适当的宽度。 到目前为止，这是我的代码：

friendStackView.autoresizingMask = .flexibleWidth
friendStackView.translatesAutoresizingMaskIntoConstraints = false

let friendView = Bundle.main.loadNibNamed("FriendView", owner: self, options: nil)?.first as! FriendViewController
friendStackView.addArrangedSubview(friendView)
friendView.heightAnchor.constraint(equalToConstant: 150).isActive = true
friendView.widthAnchor.constraint(equalToConstant: 120).isActive = true

它导致以下调试：

[LayoutConstraints] Unable to simultaneously satisfy constraints.
    Probably at least one of the constraints in the following list is one you don't want. 
    Try this: 
        (1) look at each constraint and try to figure out which you don't expect; 
        (2) find the code that added the unwanted constraint or constraints and fix it. 
(
    "<NSLayoutConstraint:0x14eb9eb0 UIStackView:0x14ee6ed0.width == 500   (active)>",
    "<NSLayoutConstraint:0x14ef83f0 XXX.FriendViewController:0x14ef2090.width == 120   (active)>",
    "<NSLayoutConstraint:0x14def090 'UISV-canvas-connection' UIStackView:0x14ee6ed0.leading == XXX.FriendViewController:0x14ef2090.leading   (active)>",
    "<NSLayoutConstraint:0x14def230 'UISV-canvas-connection' H:[XXX.FriendViewController:0x14ef2090]-(0)-|   (active, names: '|':UIStackView:0x14ee6ed0 )>"
)

Will attempt to recover by breaking constraint 
<NSLayoutConstraint:0x14ef83f0 XXX.FriendViewController:0x14ef2090.width == 120   (active)>

Answer 1

您在这里有一个冲突，stackView width = 500，并且您正在尝试提供应该填充整个宽度120的子视图

"<NSLayoutConstraint:0x14eb9eb0 UIStackView:0x14ee6ed0.width == 500   (active)>",
"<NSLayoutConstraint:0x14ef83f0 XXX.FriendViewController:0x14ef2090.width == 120