Cannot add NSLayoutContraints for a custom UIButton - ios

Question

At a loss for what I am doing wrong, here is my custom UIButton:
import UIKit
class IteratorChevronButton: UIButton {
required init() {
super.init(frame: .zero)
self.setBackgroundImage(UIImage(named: "icon-chevron-right"), for: .normal)
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
Usage of IteratorChevronButton in a UIView class:
var btnNext: IteratorChevronButton {
let btn = IteratorChevronButton()
btn.translatesAutoresizingMaskIntoConstraints = false
return btn
}
func doInit() {
self.addSubview(btnNext)
self.addConstraint(NSLayoutConstraint(item: btnNext, attribute: .width, relatedBy: .equal,
toItem: nil, attribute: .notAnAttribute, multiplier: 1.0, constant: 128))
self.addConstraint(NSLayoutConstraint(item: btnNext, attribute: .height, relatedBy: .equal,
toItem: nil, attribute: .notAnAttribute, multiplier: 1.0, constant: 128))
self.addConstraint(NSLayoutConstraint(item: btnNext, attribute: .centerY, relatedBy: .equal, toItem: self, attribute: .centerY, multiplier: 1.0, constant: 0))
self.addConstraint(NSLayoutConstraint(item: btnNext, attribute: .trailing, relatedBy: .equal, toItem: self, attribute: .trailing, multiplier: 1.0, constant: 10))
}
I am getting the following error:
I tried to make btnNext lazy but I get the following error:
Here is the code for my custom UIView class:
import UIKit
import AVFoundation
import RealmSwift
enum PlayerError {
case unknownError
}
class Player: UIView {
let circularSliderVerticalPostionString:String = "75"
let circularSliderWidthString:String = "180"
let circularSliderHeightString = "180"
var circularSliderWidth:CGFloat!
var circularSliderHeight:CGFloat!
let uiImageIconClose = UIImage(named: "icon-close")
var movieDimension: CGSize = CGSize.zero
var imageGenerator: AVAssetImageGenerator!
var duration: CMTime = CMTimeMake(0, 30)
var avPlayerLayer: AVPlayerLayer?
var avPlayer: AVPlayer!
var startedDragging: Bool = false
var ready: Bool = false
var gForce: Double = 0.0
var isInDoublePlayer:Bool = false //used as a User Runtime Define Attribute in DoublePlayerViewController.xib
lazy var canvas: DrawingLayerView = {
let dv = DrawingLayerView()
return dv
}()
//Set this variable to swithch between normal playback and slow mo
var playSlowMo: Bool {
get {
return playerToolBar.playUsingTimer
}
set {
playerToolBar.playUsingTimer = newValue
}
}
//This when set the playback will resume after user stop dragging... I think its worth showing to
//some of the customers, if I were a player I would like it to be like this :)
var continuePlaybackWhenUserStopDragging: Bool {
get {
return playerToolBar.autoPlayWhenStopDragging
}
set {
playerToolBar.autoPlayWhenStopDragging = newValue
}
}
var playbackComlete: ((_ error: PlayerError?) -> Void)? = nil
lazy var controlBarSize: CGSize = {
return CGSize(width: self.bounds.width*3/4, height: 100)
}()
lazy var playerToolBar: PlayerToolBar = {[unowned self] in
let bar = PlayerToolBar(frame: CGRect.zero)
bar.translatesAutoresizingMaskIntoConstraints = false
self.addSubview(bar)
return bar
}()
let controlsBar: UIView = {
let view = UIView()
view.translatesAutoresizingMaskIntoConstraints = false
return view
}()
lazy var closeButton: UIButton = {
let btn = ExtendedBoundsButton(type: .custom)
btn.translatesAutoresizingMaskIntoConstraints = false
btn.setImage(self.uiImageIconClose, for: UIControlState())
btn.setTitleColor(UIColor.blue, for: UIControlState())
btn.isHidden = true
self.addSubview(btn)
return btn
}()
lazy var progressLabel: UILabel = {
let label = UILabel()
label.textColor = UIColor.white
return label
}()
var btnNext: IteratorChevronButton {
let btn = IteratorChevronButton()
btn.translatesAutoresizingMaskIntoConstraints = false
return btn
}
lazy var chevronImageRight: UIImageView = {
let image = UIImage(named:"icon-chevron-right")!
let imageView = UIImageView(image: image)
imageView.contentMode = .scaleToFill
imageView.translatesAutoresizingMaskIntoConstraints = false
return imageView
}()
lazy var circularSlider: BWCircularSliderView = {
let cs = BWCircularSliderView()
cs.translatesAutoresizingMaskIntoConstraints = false
cs.frame.size.width = self.circularSliderWidth
cs.frame.size.height = self.circularSliderHeight
return cs
}()
var exporter: AVAssetExportSession? = nil
var autoPlay: Bool = false
var progressTimer: Timer?
var movieDidPlay: (()->Void?)? = nil
var onTap: (()-> Void)?
override init(frame: CGRect) {
super.init(frame: frame)
doInit()
}
func doInit() {
self.circularSliderWidth = CGFloat(Int(circularSliderWidthString)!)
self.circularSliderHeight = CGFloat(Int(circularSliderHeightString)!)
self.addSubview(chevronImageRight)
self.addSubview(progressLabel)
self.addSubview(circularSlider)
self.addSubview(btnNext)
self.addConstraint(NSLayoutConstraint(item: btnNext, attribute: .width, relatedBy: .equal,
toItem: nil, attribute: .notAnAttribute, multiplier: 1.0, constant: 128))
self.addConstraint(NSLayoutConstraint(item: btnNext, attribute: .height, relatedBy: .equal,
toItem: nil, attribute: .notAnAttribute, multiplier: 1.0, constant: 128))
self.addConstraint(NSLayoutConstraint(item: btnNext, attribute: .centerY, relatedBy: .equal, toItem: self, attribute: .centerY, multiplier: 1.0, constant: 0)
)
self.addConstraint(NSLayoutConstraint(item: btnNext, attribute: .trailing, relatedBy: .equal, toItem: self, attribute: .trailing, multiplier: 1.0, constant: 10))
self.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:|-\(circularSliderVerticalPostionString)-[circularSlider(\(circularSliderWidthString))]", options: [], metrics: nil, views: ["circularSlider": circularSlider]))
self.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "H:[circularSlider(\(circularSliderHeightString))]|", options: [], metrics: nil, views: ["circularSlider": circularSlider]))
self.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:[toolbar(100)]-0-|", options: [], metrics: nil, views: ["toolbar": playerToolBar]))
self.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "H:|[toolbar]|", options: [], metrics: nil, views: ["toolbar": playerToolBar]))
self.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:|-35-[btn(40)]", options: [], metrics: nil, views: ["btn": closeButton]))
self.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "H:[btn(40)]-10-|", options: [], metrics: nil, views: ["btn": closeButton]))
closeButton.addTarget(self, action: #selector(onClose), for: .touchUpInside)
}
func onClose() {
if !ready {
return
}
if let periodicTimeObserver = playerToolBar.periodicTimeObserver {
self.avPlayer.removeTimeObserver(periodicTimeObserver)
}
self.avPlayer.pause()
progressTimer?.invalidate()
playbackComlete?(nil)
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
doInit()
}
override func layoutSubviews() {
super.layoutSubviews()
playerToolBar.isInDoublePlayer = self.isInDoublePlayer
self.circularSlider.isHidden = self.isInDoublePlayer
self.circularSlider.gForce = self.gForce
if let avPlayerLayer = avPlayerLayer {
avPlayerLayer.bounds = self.bounds
avPlayerLayer.position = CGPoint(x: self.bounds.width/2, y: self.bounds.height/2)
playerToolBar.avPlayer = avPlayer
playerToolBar.setupMovieScrollBar()
if autoPlay {
autoPlay = false
play()
}
movieDidPlay?()
}
progressLabel.frame = CGRect(x: frame.size.width/2-100, y: frame.size.height/2-15, width: 200, height: 30)
addSubview(canvas)
addSubview(playerToolBar)
addSubview(closeButton)
canvas.frame = bounds
}
func onExportTimer(_ sender: AnyObject) {
guard let exporter = exporter else {
return
}
progressLabel.text = "Processing " + String(Int(exporter.progress*100) ) + "%"
}
func mergeFiles(_ items: [String], assetWithOnset: String?, mergeComplete: #escaping (_ fileName: String?)->Void) -> Void {
if (assetWithOnset == nil) {
mergeComplete(items.first!)
return
}
let composition = AVMutableComposition()
let track:AVMutableCompositionTrack = composition.addMutableTrack(withMediaType: AVMediaTypeVideo, preferredTrackID: CMPersistentTrackID())
var insertTime = kCMTimeZero
for item in items {
let sourceAsset = AVAsset(url: URL(fileURLWithPath: FileUtility.getPathForFileMovieDirectory(item)))
let tracks = sourceAsset.tracks(withMediaType: AVMediaTypeVideo)
print("\(item) \(sourceAsset.isPlayable)") // print true
print(sourceAsset.isExportable) // print true
print(sourceAsset.isReadable) // print true
if tracks.count > 0 {
let assetTrack:AVAssetTrack = tracks[0] as AVAssetTrack
do {
try track.insertTimeRange(CMTimeRangeMake(kCMTimeZero,sourceAsset.duration), of: assetTrack, at: insertTime)
insertTime = CMTimeAdd(insertTime, sourceAsset.duration)
} catch {
mergeComplete(nil)
return
}
}
}
let fusedFileName = "fused_" + assetWithOnset!
let fusedFilePath = FileUtility.getPathForFileMovieDirectory(fusedFileName)
let fusedFileUrl = URL(fileURLWithPath: fusedFilePath)
do {
//in case the file merging fails, the residual file will cause
//the file export fail everytime as the file exist
try FileManager.default.removeItem(atPath: fusedFilePath)
} catch {
}
exporter = AVAssetExportSession(asset: composition, presetName: AVAssetExportPreset1280x720)
guard let exporter = exporter else {
return
}
exporter.outputURL = fusedFileUrl
exporter.outputFileType = AVFileTypeQuickTimeMovie
progressTimer = Timer.scheduledTimer(timeInterval: 0.01, target: self, selector: #selector(onExportTimer(_:)), userInfo: nil, repeats: true);
exporter.exportAsynchronously(completionHandler: {
switch exporter.status{
case AVAssetExportSessionStatus.failed:
if exporter.error != nil {
print("AVAssetExportSession failed \(exporter.error!)")
}else{
print("AVAssetExportSession failed for unknown reason")
}
mergeComplete(nil)
case AVAssetExportSessionStatus.cancelled:
if exporter.error != nil {
print("AVAssetExportSession canceled \(exporter.error!)")
}else{
print("AVAssetExportSession canceled for unknown reason")
}
mergeComplete(nil)
default:
do {
let realm = try Realm()
let movieClip = realm.object(ofType: MovieModel.self, forPrimaryKey: assetWithOnset)
try realm.write {
movieClip?.fusedFile = fusedFileName
}
//The files are released based on the usage count
MovieRepository.sharedInstance.release(file: movieClip?.fileName)
MovieRepository.sharedInstance.release(file: movieClip?.nextFile)
MovieRepository.sharedInstance.release(file: movieClip?.prevFile)
} catch {
}
mergeComplete(fusedFileName)
self.progressLabel.text = ""
self.progressLabel.isHidden = true
NotificationUtility.notifyReloadGallery()
}
})
}
func setMovies(_ items: [String], itemWithOnset asset: String?, playbackCompletion completion: #escaping ((_ error: PlayerError?) -> Void)){
playbackComlete = completion
closeButton.isHidden = false
mergeFiles(items, assetWithOnset: asset ) { [weak self] (fileName) in
DispatchQueue.main.async(execute: { () -> Void in
if let fileName = fileName, let strongSelf = self {
let asset = AVAsset(url: URL(fileURLWithPath: FileUtility.getPathForFileMovieDirectory(fileName)))
let avplayerItem = AVPlayerItem(asset: asset)
strongSelf.progressTimer?.invalidate()
strongSelf.progressLabel.removeFromSuperview()
strongSelf.duration = asset.duration
strongSelf.avPlayer = AVPlayer(playerItem: avplayerItem)
if let playerLayer = strongSelf.avPlayerLayer {
playerLayer.removeFromSuperlayer()
}
strongSelf.avPlayerLayer = AVPlayerLayer(player: strongSelf.avPlayer)
strongSelf.avPlayerLayer?.zPosition = -1 //send to back
strongSelf.self.layer.addSublayer(strongSelf.avPlayerLayer!)
NotificationCenter.default.addObserver(strongSelf, selector: #selector(Player.currentFileDidFinish(_:)), name: NSNotification.Name.AVPlayerItemDidPlayToEndTime, object: avplayerItem)
print("Duration \(Float(CMTimeGetSeconds(strongSelf.duration)))")
print("Size \(strongSelf.movieDimension)")
strongSelf.ready = true
strongSelf.autoPlay = true;
strongSelf.setNeedsLayout()
}
})
}
}
func setMovie(movieAsset: MovieModel, completion: #escaping ()->Void) {
movieDidPlay = completion
autoPlay = true
playerToolBar.playeBackTimer?.invalidate()
playerToolBar.playeBackTimer = nil
var clipNames: [String]
var assetWithOnset: String? = nil
if let fusedFile = movieAsset.fusedFile {
clipNames = [fusedFile]
} else {
assetWithOnset = movieAsset.fileName
if let nextFile = movieAsset.nextFile {
clipNames = [movieAsset.prevFile!, movieAsset.fileName!, nextFile]
} else {
clipNames = [movieAsset.prevFile!, movieAsset.fileName!]
}
}
self.setMovies(clipNames, itemWithOnset: assetWithOnset, playbackCompletion: { (err) in
})
closeButton.isHidden = true
}
func resolutionSizeForVideo(_ asset:AVAsset) -> CGSize? {
guard let track = asset.tracks(withMediaType: AVMediaTypeVideo).first else { return nil }
let size = track.naturalSize.applying(track.preferredTransform)
return CGSize(width: fabs(size.width), height: fabs(size.height))
}
//MARK: The playback methods
func pause(){
if ready {
playerToolBar.pause()
}
}
func play() {
if ready {
playerToolBar.play()
}
}
func currentFileDidFinish(_ notification: Notification) {
/* if let periodicTimeObserver = playerToolBar.periodicTimeObserver {
self.avPlayer.removeTimeObserver(periodicTimeObserver)
}
progressTimer?.invalidate()
playbackComlete?(error: nil)*/
avPlayer.seek(to: CMTimeMake(0, 30))
avPlayer.rate = 1.0
}
func stop() {
avPlayer?.pause()
avPlayer = nil
avPlayerLayer?.removeFromSuperlayer()
avPlayerLayer = nil
}
deinit {
NotificationCenter.default.removeObserver(self)
}
//MARK:
}
class CollectionViewThumbNailCell: UICollectionViewCell {
lazy var barView: UIView = {
let lbl = UIView()
lbl.contentMode = .scaleToFill
lbl.translatesAutoresizingMaskIntoConstraints = false
lbl.backgroundColor = UIColor.white
lbl.layer.cornerRadius = 2
lbl.clipsToBounds = true
return lbl
}()
override init(frame: CGRect) {
super.init(frame: frame)
contentView.addSubview(barView)
}
func configureMark(_ big: Bool) {
if big {
barView.frame = CGRect(x: bounds.size.width/2 - 2, y: 2, width: 4, height: bounds.size.height)
} else {
barView.frame = CGRect(x: bounds.size.width/2 - 2, y: bounds.size.height/2+2, width: 4, height: bounds.size.height/2)
}
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}

Answer 1

I guess error is due to this (your btnNext is not being made properly):
var btnNext: IteratorChevronButton {
let btn = IteratorChevronButton()
btn.translatesAutoresizingMaskIntoConstraints = false
return btn
}
use this syntax to make btnNext
var btnNext: IteratorChevronButton = {
let btn = IteratorChevronButton()
btn.translatesAutoresizingMaskIntoConstraints = false
return btn
}()

Answer 2

You instantiate a new button every time you access btnNext. So after adding one instance as a subview you use other instances for creating the constraints. Since those other subviews are no subviews of self the app crashes.
Make it a lazy var to instantiate it only once:
lazy var btnNext: IteratorChevronButton = {
let btn = IteratorChevronButton()
btn.translatesAutoresizingMaskIntoConstraints = false
return btn
}()
You also have to add the width and height constraint to the button itself instead of self:
btnNext.addConstraint(NSLayoutConstraint(item: btnNext, attribute: .width, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1.0, constant: 128))
btnNext.addConstraint(NSLayoutConstraint(item: btnNext, attribute: .height, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1.0, constant: 128))
Update:
As Ahmad F stated the lazy keyword is totally optional in this case. You could simply instantiate your button without it if you will definitely use it:
var btnNext: IteratorChevronButton = {
let btn = IteratorChevronButton()
btn.translatesAutoresizingMaskIntoConstraints = false
return btn
}()