我有一个名为 DropDownList 的 UIView 类，其中包含一个标签和一个按钮。该标签和按钮放置在堆栈 View 中。以下是我添加到此 View 的约束。问题是，当添加此约束时，整个 View (主视图)在设备中变黑，但在模拟器中工作。当更改按钮标题时，我还面临另一个问题，整个 View (主视图)在模拟器中变黑。我正在使用 swift 4 和 Xcode 9.0。请帮忙...
class DropDownList: UIView {
let DefaultSpace: CGFloat = 50.0
let Margin: CGFloat = 10.0
let StackViewSpacing: CGFloat = 50.0
var mDataList:[Dictionary<String,Any>] = [] {
}
var mFieldLabel: UILabel =
{
let fieldLabel = UILabel()
fieldLabel.font = AppFont
fieldLabel.textAlignment = .left
return fieldLabel
}()
var mDropDown: DropDown = DropDown()
var mDropDownBtn: UIButton = {
let btn = UIButton()
btn.setTitle("-Select-", for: .normal)
btn.setTitleColor(.black, for: .normal)
btn.titleLabel?.textAlignment = .left
btn.titleLabel?.font = AppFont
btn.addTarget(self, action:#selector(dropDownClick) , for: .touchUpInside)
return btn
}()
lazy var mStackView: UIStackView = {
let stackView = UIStackView(arrangedSubviews: [mFieldLabel, mDropDownBtn])
stackView.alignment = .center
stackView.distribution = .fill
stackView.axis = .horizontal
stackView.spacing = StackViewSpacing
stackView.translatesAutoresizingMaskIntoConstraints = false
stackView.backgroundColor = .yellow
return stackView
}()
override func awakeFromNib() {
super.awakeFromNib()
}
// MARK: - Init
init(with data:[Dictionary<String,Any>], inView: UIView, parent: DropDownList?, fieldName: String , topSpacing: CGFloat )
{
super.init(frame: CGRect(x: 0, y: 40, width: 400, height: 50))
setViews(fieldName: fieldName, data: data, inView: inView)
self.setConstaintsWithTopSpacing(inView: inView,topSpace: topSpacing, parentView: inView)
func setViews(fieldName: String, data:[Dictionary<String,Any>], inView: UIView)
{
self.translatesAutoresizingMaskIntoConstraints = false
self.mDataList = data
self.mFieldLabel.text = fieldName
DropDown.startListeningToKeyboard()
mDropDown.anchorView = mDropDownBtn
self.addSubview(mStackView)
inView.addSubview(self)
mDropDown.selectionAction = { [unowned self] (index: Int, item: String) in
print("Selected item: \(item) at index: \(index)")
self.mDropDownBtn.setTitle(item, for: .normal)
self.updateConstraints()
self.layoutIfNeeded()
}
}
// MARK: - Constraints
func setConstaintsWithTopSpacing(inView: UIView, topSpace: CGFloat, parentView: UIView)
{
if (inView.translatesAutoresizingMaskIntoConstraints)
{
inView.translatesAutoresizingMaskIntoConstraints = false
}
let leadingConstraint = NSLayoutConstraint(item: self, attribute: .leading, relatedBy: NSLayoutRelation.equal, toItem: inView, attribute: .leading, multiplier: 1, constant: Margin)
let topConstraint = NSLayoutConstraint(item: self, attribute: .top, relatedBy: NSLayoutRelation.equal, toItem: parentView, attribute: .top, multiplier: 1, constant: topSpace)
let trailingConstraint = NSLayoutConstraint(item: self, attribute: .trailing, relatedBy: NSLayoutRelation.equal, toItem: inView, attribute: .trailing, multiplier: 1, constant: Margin)
let heightConstranit = NSLayoutConstraint(item: self, attribute: .height, relatedBy: .greaterThanOrEqual, toItem: nil, attribute: .notAnAttribute, multiplier: 1, constant: 40)
inView.addConstraints([leadingConstraint, topConstraint, trailingConstraint, heightConstranit])
setStackViewConstraints()
}
func setConstaintsWithTopLayout(inView: UIView, topLayout: UILayoutSupport?)
{
if (inView.translatesAutoresizingMaskIntoConstraints)
{
inView.translatesAutoresizingMaskIntoConstraints = false
}
setStackViewConstraints()
let leadingConstraint = NSLayoutConstraint(item: self, attribute: .leading, relatedBy: NSLayoutRelation.equal, toItem: inView, attribute: .leading, multiplier: 1, constant: 10)
let topConstraint = NSLayoutConstraint(item: self, attribute: .top, relatedBy: NSLayoutRelation.equal, toItem: inView, attribute: .top, multiplier: 1, constant: 80)
let trailingConstraint = NSLayoutConstraint(item: self, attribute: .trailing, relatedBy: NSLayoutRelation.equal, toItem: inView, attribute: .trailing, multiplier: 1, constant: 10)
inView.addConstraints([leadingConstraint, topConstraint, trailingConstraint])
}
func setStackViewConstraints()
{
let leadingConstraintStackView = NSLayoutConstraint(item: mStackView, attribute: .leading, relatedBy: NSLayoutRelation.equal, toItem: self, attribute: .leading, multiplier: 1, constant: 0)
let topConstraintStackView = NSLayoutConstraint(item: mStackView, attribute: .top, relatedBy: NSLayoutRelation.equal, toItem: self, attribute: .top, multiplier: 1, constant: 0)
let trailingConstraintStackView = NSLayoutConstraint(item: mStackView, attribute: .trailing, relatedBy: NSLayoutRelation.equal, toItem: self, attribute: .trailing, multiplier: 1, constant: 0)
let bottomConstraintStackView = NSLayoutConstraint(item: mStackView, attribute: .bottom, relatedBy: NSLayoutRelation.equal, toItem: self, attribute: .bottom, multiplier: 1, constant: 0)
self.addConstraints([leadingConstraintStackView, topConstraintStackView, trailingConstraintStackView, bottomConstraintStackView])
}
}
我正在创建此类的对象和主视图的 subview 。
let sailsOfficeDl = DropDownList(with: [dic, dic1], inView: self.view, fieldName: "Sales Office", topLayout: self.topLayoutGuide)
最佳答案
当我创建 UIView 的子类时，我之前注意到了相同的行为
我们在初始化类时明确需要将背景颜色设置为 Clear
init(frame:CGRect,distance:CGFloat,width:CGFloat)
{
super.init(frame: frame)
/// Here I need to set the BackGround color as Clear
/// If I comment this line Output shown is output 1
/// if I dont comment this Line Output is shown in output 2
self.backgroundColor = UIColor.clear
self.isUserInteractionEnabled = true
self.distance = distance
self.textBgColor = UIColor.red
self.labelText = "Sample"
self.bgColor = UIColor.black
self.viewWidth = width
self.textFontSize = 14
self.frame = CGRect(x: 0, y: 0, width: (distance*2)+width, height: (distance*2)+width)
}
输出 1 
输出 2 
在output-1中我的整个矩形变成黑色 在输出 2 中，只有我绘制的上下文是黑色，因为我将其设置为黑色
希望这对您有帮助
关于ios - 在 Swift 中以编程方式添加自动布局约束将 uiview 变为黑色，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/49912665/