无法设置自定义视图的限制，斯威夫特
问题描述：
我不能设置领导和主要约束的tableViewCell内的自定义视图，我也得到它说无法设置自定义视图的限制，斯威夫特
大小暧昧profileImageView
的错误信息
但是我能够将profileImageView居中到单元格的中心，但是当我尝试设置leadingAnchor（如下面的函数setUp所示）时，视图的中心被使用而不是leadingAnchor。
这就是我的profileImageView显示方式，它显示在单元格的左上角。
class CustomCell: UITableViewCell {
var profileImageView : ProfileImageView!
func setUp(_viewController : UIViewController){
let profileImageFrame = CGRect(x: 0, y: 0, width: 150, height: 150) // Creating a frame for the imageView
profileImageView = ProfileImageView(frame: profileImageFrame, viewController: _viewController, photoWidth: 100.0)
profileImageView.translatesAutoresizingMaskIntoConstraints = false
contentView.addSubview(profileImageView) // ContentView refers to the cell contentView
profileImageView.leadingAnchor.constraint(equalTo: contentView.leadingAnchor).isActive = true
profileImageView.topAnchor.constraint(equalTo: contentView.topAnchor).isActive = true
}
}
使用下面的类来创建profileImageView
class ProfileImageView: UIView,
UIImagePickerControllerDelegate,
UINavigationControllerDelegate,
TOCropViewControllerDelegate{
// FOR IMAGE CROPPER
var photoDiameter: CGFloat = 100.0
var photoFrameViewPadding : CGFloat = 2.0
let addButtonTitle = "add\nphoto"
var didSetupConstraints: Bool = false
var photoFrameView : UIView!
var addPhotoButton : UIButton!
var editPhotoButton : UIButton!
var currentViewController = UIViewController()
init(frame: CGRect, viewController : UIViewController, photoWidth: CGFloat){
//Initialise values
photoFrameView = UIView()
addPhotoButton = UIButton()
editPhotoButton = UIButton()
currentViewController = viewController
photoDiameter = photoWidth
super.init(frame: frame)
setup()
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
func setup(){
// ---------------------------
// Add the frame of the photo.
// ---------------------------
let photoImageViewOrigin = self.frame.origin
self.frame = CGRect(x: photoImageViewOrigin.x, y: photoImageViewOrigin.y, width: photoDiameter, height: photoDiameter + 20.0)
self.backgroundColor = UIColor.clear
photoFrameView?.backgroundColor = UIColor(red: 182/255.0, green: 182/255.0, blue: 187/255.0, alpha: 1.0)
//photoFrameView.backgroundColor = UIColor.gray
photoFrameView.translatesAutoresizingMaskIntoConstraints = false
photoFrameView.layer.masksToBounds = true
photoFrameView.layer.cornerRadius = (photoDiameter + photoFrameViewPadding)/2
self.addSubview(photoFrameView!)
// ----------------
// Add constraints.
// ----------------
//self.setNeedsUpdateConstraints()
self.setConstraints()
}
func setConstraints() {
//super.updateViewConstraints()
if didSetupConstraints {
return
}
// ---------------------------
// The frame of the photo.
// ---------------------------
var constraint = NSLayoutConstraint(item: photoFrameView, attribute: .width, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1.0, constant: (photoDiameter + photoFrameViewPadding))
photoFrameView?.addConstraint(constraint)
constraint = NSLayoutConstraint(item: photoFrameView, attribute: .height, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1.0, constant: (photoDiameter + photoFrameViewPadding))
photoFrameView?.addConstraint(constraint)
constraint = NSLayoutConstraint(item: photoFrameView, attribute: .centerY, relatedBy: .equal, toItem: self, attribute: .centerY, multiplier: 1.0, constant: 0.0)
self.addConstraint(constraint)
constraint = NSLayoutConstraint(item: photoFrameView, attribute: .centerX, relatedBy: .equal, toItem: self, attribute: .centerX, multiplier: 1.0, constant: 0.0)
self.addConstraint(constraint)
// ---------------------------
// The button "add photo".
// ---------------------------
constraint = NSLayoutConstraint(item: addPhotoButton, attribute: .width, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1.0, constant: photoDiameter)
addPhotoButton?.addConstraint(constraint)
constraint = NSLayoutConstraint(item: addPhotoButton, attribute: .height, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1.0, constant: photoDiameter)
addPhotoButton?.addConstraint(constraint)
constraint = NSLayoutConstraint(item: addPhotoButton, attribute: .centerX, relatedBy: .equal, toItem: photoFrameView, attribute: .centerX, multiplier: 1.0, constant: 0.0)
self.addConstraint(constraint)
constraint = NSLayoutConstraint(item: addPhotoButton, attribute: .centerY, relatedBy: .equal, toItem: photoFrameView, attribute: .centerY, multiplier: 1.0, constant: 0.0)
self.addConstraint(constraint)
// ---------------------------
// The button "edit photo".
// ---------------------------
constraint = NSLayoutConstraint(item: editPhotoButton, attribute: .centerX, relatedBy: .equal, toItem: self, attribute: .centerX, multiplier: 1.0, constant: 0.0)
self.addConstraint(constraint)
constraint = NSLayoutConstraint(item: editPhotoButton, attribute: .top, relatedBy: .equal, toItem: photoFrameView, attribute: .bottom, multiplier: 1.0, constant: -5.0)
self.addConstraint(constraint)
didSetupConstraints = true
}
}
答
你的错误是在这里：
profileImageView.leadingAnchor.constraint(equalTo: contentView.leadingAnchor).isActive = true
profileImageView.topAnchor.constraint(equalTo: contentView.topAnchor).isActive = true
topAnchor/leadingAnchor.constraint不设置约束，它返回可以添加到视图hiera中的约束rchy。因此，您的profileImageView实际上没有限制。
此外，您没有在仅限于帧的约束中设置它的宽度和高度。这是你的警告的来源。
解决方案
let leadingConstraint = profileImageView.leadingAnchor.constraint(equalTo: contentView.leadingAnchor)
let topConstraint = profileImageView.topAnchor.constraint(equalTo: contentView.topAnchor)
//These are just examples, make whichever constraints that you need
let widthConstraint = NSLayoutConstraint(item: profileImageView, attribute: .width, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1.0, constant: 150.0)
let heightConstraint = NSLayoutConstraint(item: profileImageView, attribute: .height, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1.0, constant: 150.0)
contentView.addConstraints([leadingConstraint,topConstraint, widthConstraint, heightConstraint])