asdisplay-node-layout.swift

import UIKit
import AsyncDisplayKit

class CommentPreviewViewController: ASViewController<ASDisplayNode> {
    let rootNode = ASDisplayNode()
    let textNode = ASTextNode()
    
    init() {
        super.init(node: rootNode)

        textNode.attributedText = NSAttributedString(string: "Lorem ipsum dolor sit amet.", attributes: [NSAttributedString.Key.font: UIFont.systemFont(ofSize: 15.0)])
        
        rootNode.automaticallyManagesSubnodes = true
        
        rootNode.layoutSpecBlock = { (node, constrainedSize) in
            return ASInsetLayoutSpec(insets: UIEdgeInsets(top: 10.0, left: 10.0, bottom: 10.0, right: 10.0), child: self.textNode)
        }
    }
    
    required init?(coder aDecoder: NSCoder) { fatalError("\(#file) does not implement coder.") }
    
    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        
        let layout = rootNode.layoutThatFits(ASSizeRangeMake(CGSize(width: view.bounds.width, height: CGFloat.greatestFiniteMagnitude)))
        print(layout.size.height) // Error
    }
}