Swift Playground error: Execution was interrupted, reason: signal SIGABRT

Question

如何调试这个错误？似乎没有额外的错误描述。

失败的代码：

import UIKit
import PlaygroundSupport

let containerView = UIView(frame: CGRect(x: 0, y: 0, width: 300, height: 300))
containerView.backgroundColor = UIColor.white

let stackView = UIStackView()
stackView.translatesAutoresizingMaskIntoConstraints = false
containerView.addSubview(stackView)
stackView.addConstraint(.init(item: stackView, attribute: .top, relatedBy: .equal, toItem: containerView, attribute: .top, multiplier: 1, constant: 0))
stackView.addConstraint(.init(item: stackView, attribute: .leading, relatedBy: .equal, toItem: containerView, attribute: .leading, multiplier: 1, constant: 0))

PlaygroundPage.current.liveView = containerView // error: Execution was interrupted, reason: signal SIGABRT.

完整错误：

error: Execution was interrupted, reason: signal SIGABRT. The process has been left at the point where it was interrupted, use "thread return -x" to return to the state before expression evaluation.

完整控制台日志：

libc++abi.dylib: terminating with uncaught exception of type NSException

Answer 1

问题是您将约束添加到 stackView 而不是 containerView。

documentation for addConstraint 状态

The constraint to be added to the view. The constraint may only reference the view itself or its subviews.

containerView是stackView的父视图，不是子视图。

如果您更改代码以将约束添加到 containerView，它将运行

containerView.addConstraint(.init(item: stackView, attribute: .top, relatedBy: .equal, toItem: containerView, attribute: .top, multiplier: 1, constant: 0))
containerView.addConstraint(.init(item: stackView, attribute: .leading, relatedBy: .equal, toItem: containerView, attribute: .leading, multiplier: 1, constant: 0))

您可能想要添加尾部约束和底部约束，以便堆栈视图填充整个容器视图。当然，您还需要添加一个 arrangedSubview 以便堆栈视图中实际上有一些内容。

通过引用布局指南添加约束通常比这种更陈旧、更冗长的方法更简单：

import UIKit
import PlaygroundSupport

let containerView = UIView(frame: CGRect(x: 0, y: 0, width: 300, height: 300))
containerView.backgroundColor = UIColor.white

let stackView = UIStackView()
stackView.translatesAutoresizingMaskIntoConstraints = false
containerView.addSubview(stackView)

stackView.leadingAnchor.constraint(equalTo: containerView.leadingAnchor).isActive = true
stackView.trailingAnchor.constraint(equalTo: containerView.trailingAnchor).isActive = true
stackView.topAnchor.constraint(equalTo: containerView.topAnchor).isActive = true
stackView.bottomAnchor.constraint(equalTo: containerView.bottomAnchor).isActive = true


let label = UILabel()
label.text = "Hello world"
label.textColor = .black
stackView.addArrangedSubview(label)
PlaygroundPage.current.liveView = containerView

Swift Playground error: Execution was interrupted, reason: signal SIGABRT

Swift Playground error: Execution was interrupted, reason: signal SIGABRT

ios

swift

swift-playground