Cannot move UILabel position programatically - ios

Question

I have a file for the View section of app, where i have all the labels and images that i intent to use, this is what i have in my DetailViewTableCell class, which inherits from UIView.
class DetailViewTableCell: UIView {
var detailMainImage: UIImageView = UIImageView()
var detailName: UILabel = UILabel()
var detailType: UILabel = UILabel()
var detailHeart: UIImageView = UIImageView()
}
Now i move to my DetailViewController class, here i try and add the label, the label is added but it appears always at top left corner at 0,0 coordinate, when i try and add constraints for position, i always get error, now i can try
detailMain.detailName.frame.origin.x = 30
but i get error:
Constraint items must each be a view or layout guide.
In any case i do not wish to use this approach but more something like this
NSLayoutConstraint(item: detailMain.detailName, attribute: .leading, relatedBy: .equal, toItem: detailMain.detailName.superview, attribute: .leading, multiplier: 1, constant: 20).isActive = true
but i get the same above error, my over all code is this:
self.view.addSubview(detailMain.detailName)
detailMain.detailName.translatesAutoresizingMaskIntoConstraints = false
detailMain.detailName.heightAnchor.constraint(equalToConstant: 25).isActive = true
detailMain.detailName.widthAnchor.constraint(greaterThanOrEqualToConstant: 100).isActive = true
detailMain.detailName.font = UIFont(name: "Rubik-Medium", size: 30)
detailMain.detailName.backgroundColor = UIColor.white
detailMain.detailName.textColor = UIColor.black
Which works perfectly fine but the moment i try and constraints, the error come up, this is how the app shows up with out constraints and name at top most left corner
////////UPDATE
So here is my new DetailViewTableCell,
import UIKit
class DetailViewTableCell: UIView {
var detailMainImage: UIImageView = UIImageView()
var detailName: UILabel = UILabel()
var detailType: UILabel = UILabel()
var detailHeart: UIImageView = UIImageView()
override init(frame: CGRect) {
super.init(frame: frame)
[detailMainImage, detailName, detailType, detailHeart].forEach {
$0.translatesAutoresizingMaskIntoConstraints = false
addSubview($0)
}
NSLayoutConstraint.activate([
// constrain main image to all 4 sides
detailMainImage.topAnchor.constraint(equalTo: topAnchor),
detailMainImage.leadingAnchor.constraint(equalTo: leadingAnchor),
detailMainImage.trailingAnchor.constraint(equalTo: trailingAnchor),
detailMainImage.bottomAnchor.constraint(equalTo: bottomAnchor),
// activate the height contraint
// constrain detailType label
// 30-pts from Leading
// 12-pts from Top
detailType.leadingAnchor.constraint(equalTo: leadingAnchor, constant: 30.0),
detailType.topAnchor.constraint(equalTo: topAnchor, constant: 12.0),
// constrain detailName label
// 30-pts from Leading
// 12-pts from Bottom
detailName.leadingAnchor.constraint(equalTo: leadingAnchor, constant: 30.0),
detailName.bottomAnchor.constraint(equalTo: bottomAnchor, constant: -12.0),
// constrain detailHeart image
// 12-pts from Trailing
// 12-pts from Bottom
// width: 24 height: equal to width (1:1 square)
detailHeart.trailingAnchor.constraint(equalTo: trailingAnchor, constant: -12.0),
detailHeart.bottomAnchor.constraint(equalTo: bottomAnchor, constant: -12),
detailHeart.widthAnchor.constraint(equalToConstant: 24),
detailHeart.heightAnchor.constraint(equalTo: detailHeart.widthAnchor)
])
}
required init?(coder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
and this 2 lines is what i add to my Detail view controller in viewDidLoad
let v = DetailViewTableCell()
detailTableView.tableHeaderView = v
Also i add this function
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
// this is needed to allow the header view's content
// to determine its height
guard let headerView = detailTableView.tableHeaderView else {
return
}
let size = headerView.systemLayoutSizeFitting(UIView.layoutFittingCompressedSize)
if headerView.frame.size.height != size.height {
headerView.frame.size.height = size.height
detailTableView.tableHeaderView = headerView
detailTableView.layoutIfNeeded()
}
}
then in my viewForHeaderInSection inbuilt function i add this
func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
let headerView = UIView()
tableView.rowHeight = 80
headerView.translatesAutoresizingMaskIntoConstraints = false
headerView.widthAnchor.constraint(equalToConstant: UIScreen.main.bounds.width).isActive = true
headerView.heightAnchor.constraint(equalToConstant: 400).isActive = true
detailMain.detailMainImage.translatesAutoresizingMaskIntoConstraints = false
detailMain.detailMainImage.heightAnchor.constraint(equalToConstant: 400).isActive = true
detailMain.detailMainImage.widthAnchor.constraint(equalToConstant: UIScreen.main.bounds.width).isActive = true
detailMain.detailMainImage.image = UIImage(named: restaurant.image)
detailMain.detailMainImage.contentMode = .scaleAspectFill
detailMain.detailMainImage.clipsToBounds = true
headerView.addSubview(detailMain.detailMainImage)
//Add the name
detailMain.detailName.text = restaurant.name
headerView.addSubview(detailMain.detailName)
return headerView
}
but still same position , is there any thing i add to add or remove from my code

Answer 1

You didn't show where you *want the labels, but this should get you going...
In your "header view" class:
add your elements: detailMainImage, detailName, etc...
set their properties and constraints as desired
You can get auto-layout to use the constraints you've setup in the header view to automatically determine its height:
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
// this is needed to allow the header view's content
// to determine its height
guard let headerView = tableView.tableHeaderView else {
return
}
let size = headerView.systemLayoutSizeFitting(UIView.layoutFittingCompressedSize)
if headerView.frame.size.height != size.height {
headerView.frame.size.height = size.height
tableView.tableHeaderView = headerView
tableView.layoutIfNeeded()
}
}
So, here's a complete example:
class TestHeaderTableViewController: UITableViewController {
override func viewDidLoad() {
super.viewDidLoad()
// instantiate the header view
let v = DetailTableHeaderView()
// set it as the tableHeaderView
tableView.tableHeaderView = v
}
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
// this is needed to allow the header view's content
// to determine its height
guard let headerView = tableView.tableHeaderView else {
return
}
let size = headerView.systemLayoutSizeFitting(UIView.layoutFittingCompressedSize)
if headerView.frame.size.height != size.height {
headerView.frame.size.height = size.height
tableView.tableHeaderView = headerView
tableView.layoutIfNeeded()
}
}
}
class DetailTableHeaderView: UIView {
var detailMainImage: UIImageView = UIImageView()
var detailName: UILabel = UILabel()
var detailType: UILabel = UILabel()
var detailHeart: UIImageView = UIImageView()
override init(frame: CGRect) {
super.init(frame: frame)
commonInit()
}
required init?(coder: NSCoder) {
super.init(coder: coder)
commonInit()
}
func commonInit() -> Void {
backgroundColor = .white
// give the heart image view a background color so we can see its frame
detailHeart.backgroundColor = .red
if let img = UIImage(named: "teacup") {
detailMainImage.image = img
}
// give labels some text so we can see them
detailType.text = "Detail Type"
detailName.text = "Detail Name"
// setup fonts for labels as desired
//detailName.font = UIFont(name: "Rubik-Medium", size: 30)
// I don't have "Rubik" so this is with the system font
detailName.font = UIFont.systemFont(ofSize: 30, weight: .bold)
detailName.backgroundColor = UIColor.white
detailName.textColor = UIColor.black
detailType.textColor = .white
[detailMainImage, detailName, detailType, detailHeart].forEach {
$0.translatesAutoresizingMaskIntoConstraints = false
addSubview($0)
}
// give main image a height
// set its Priority to 999 to prevent layout constraint conflict warnings
let mainImageHeightAnchor = detailMainImage.heightAnchor.constraint(equalToConstant: 300.0)
mainImageHeightAnchor.priority = UILayoutPriority(rawValue: 999)
NSLayoutConstraint.activate([
// constrain main image to all 4 sides
detailMainImage.topAnchor.constraint(equalTo: topAnchor),
detailMainImage.leadingAnchor.constraint(equalTo: leadingAnchor),
detailMainImage.trailingAnchor.constraint(equalTo: trailingAnchor),
detailMainImage.bottomAnchor.constraint(equalTo: bottomAnchor),
// activate the height contraint
mainImageHeightAnchor,
// constrain detailType label
// 30-pts from Leading
// 12-pts from Top
detailType.leadingAnchor.constraint(equalTo: leadingAnchor, constant: 30.0),
detailType.topAnchor.constraint(equalTo: topAnchor, constant: 12.0),
// constrain detailName label
// 30-pts from Leading
// 12-pts from Bottom
detailName.leadingAnchor.constraint(equalTo: leadingAnchor, constant: 30.0),
detailName.bottomAnchor.constraint(equalTo: bottomAnchor, constant: -12.0),
// constrain detailHeart image
// 12-pts from Trailing
// 12-pts from Bottom
// width: 24 height: equal to width (1:1 square)
detailHeart.trailingAnchor.constraint(equalTo: trailingAnchor, constant: -12.0),
detailHeart.bottomAnchor.constraint(equalTo: bottomAnchor, constant: -12),
detailHeart.widthAnchor.constraint(equalToConstant: 24),
detailHeart.heightAnchor.constraint(equalTo: detailHeart.widthAnchor),
])
}
}
For this example, I just set the background color of the "heart" image view to red, and I clipped the teacup out of your image:
And this is the result:
Edit - to use the custom view as a Section header view...
Use the same DetailTableHeaderView class from above, but change the table view controller as follows:
class TestSectionHeaderTableViewController: UITableViewController {
override func viewDidLoad() {
super.viewDidLoad()
tableView.sectionHeaderHeight = UITableView.automaticDimension
tableView.estimatedSectionHeaderHeight = 300
}
override func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
if section == 0 {
let v = DetailTableHeaderView()
// for example implementation...
if let img = UIImage(named: "teacup") {
v.detailMainImage.image = img
}
v.detailName.text = "Testing the Name"
// for your implementation...
//if let img = UIImage(named: restaurant.image) {
// v.detailMainImage.image = img
//}
//v.detailName.text = restaurant.name
return v
}
return nil;
}
}